MASTER GARDENER INSECT GUIDE for Ornamentals and

A A MASTER GARDENER INSECT GUIDE for Ornamentals and Preface and Acknowledgments Contents Diagnosis of Insects and Mites ................... 1...
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MASTER GARDENER INSECT GUIDE for Ornamentals and

Preface and Acknowledgments

Contents

Diagnosis of Insects and Mites

...................

1

Steps to Diagnosis; Narrowing Down the Possibilities; Common Mistakes in Diagnosis

Keys to Signs and Symptoms of Some Insect, Mite, and Slug Pests

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3

Sooty Molds on Ornamentals; Detecting and

Monitoring Insect Pests of T u ~ g r a s s

Insects, Mites, and Other Pests

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7

What Are Insects?; Grasshoppers and Mole Crickets (Orthptera); Bugs, Aphids, Scales, and Others; Beetles; Moths and Butterjlies; Flies, Midges, and kafminers (Diptera); Ants, Bees, Sayflies, and Gall Wasps; What Are Mites?; Other Kinds of Pests

Cultural and Biological Control of Insect and Mite Pests

.................................................... Cultural Control; Biological Control Calendars of Pest Appearance .................. Index .............................................................................. References ....................................................................

27 29 35

36

This publication has been developed to take the place of North Carolina Agricultural Extension Service Insect Notes as training materialfor Master Gardeners. It presents a systematic (although somewhat cursory) review of the most commonly encountered insect and related pests of turf and ornamental plants. Although useful in answering specijic questions, the Insect Notes lack systematic organization. This guide draws together informationfrom the Insect Notes and other sources previously used for Master Gardener training. The illustrations throughout this guide are intended to assist you in identifying insects and mites. They are not copyrighted and may be reproduced without permission. We are grateful for the many excellent illustrations by Ponglerd Kooaroon, Susan Van Gieson, F. Eugene Wood, Todd Cole, Pitisaron Sakonsatayadorn, James Willcox, L. L. Deitz, and Vanya Mullinax. Many thanks to the following for providing illustrations: James R Baker, the United States Department of Agriculture, the Kansas Department of Agriculture, the Colorado Extension Service, and the United States Department oj Health, Education, and Welfare. Special thanks are extended to Maurice H. Farrier, L. L. Deitz, and Jack D. DeAngelis of North Carolina State University,to N. Fred Miller, David Vann Barkley, Edwin F. Nolley, and Toby D. Bost of the North Carolina Agricultural Extension Service; and to Master Gardener Althea Roth of Catawba Countyfor reviewing this manuscript. The time they spent is well appreciated. -JRB and RL.B June 1990

Illustration Credits

Illustrations are not drawn to the same scale. Ponglerd Kooaroon: Figures 28; 29; 32; 35B, C;40A, D; 41A; 43; 44A, B; 46; 47A to C;14A; 15A; 24A, B; 25A to H; 26F to H; 48G to J; 50; 54; 55A, B; 560; 62A Susan Van Gieson: Figures 6; 37B; 458 to D; 120; 15B, C;188 to D; 251; 26E; 27H; 53 F. Eugene Wood. Figures 30A; 1 OA Todd Cole: Figures 30B to D Pitisaron Sakonsatqadom: Figure 33A James Willcox: Figures IOB to F; 12C; 55C, D L.. L..Dietz Figure 16A VanyaMullinax: Figure 57 James R. Baker: Figures 2; 3; 4; 30E; 33B, E; 34; 37A, C;408, C;41B; 440, E; 45A; 470; 9; I2B; I4B, C; 17; 18A; 19 to 23; 24C, D; 26A to D; 27A to G; 48A to G; 49; 51; 52G; 8; 56B, C;58A; 59; 60; 61A, B United States Lkp&mrzt of Agriculture: Figures I ; 5; 31; 33C, D, F; 36; 370; 38; 42A, C;11; 13; 16B to H; 52A to F; 56A; 58B; 62B Kansas Lkp&mnt of Agriculture: Figure 35A Colorado Extension Service: Figure 39 United States Department of HeaJth, Education, and Welfare: Figures 44C, F

DIAGNOSIS OF INSECT AND MITE PESTS

s Master Gardeners you probably encounter many insect and mite problems that you can solve easily. Other problems yield only to determined effort. However, you may find that you have to refer some problems to your county Extension agent for proper diagnosis. In a few of the most difficult cases, the agent will have to refer the problem to the Plant Disease and Insect Clinic. Of these latter cases, a few will be unsolvable. You should not feel inadequate if you encounter unsolvable cases. Master Gardeners are not expected to be able to diagnose all insect problems. This guide will help you diagnose many insect and mite problems and to decide whether to bring a particular problem to the attention of the county agent.

Steps to Diagnosis When confronted with a’problem, people often tend to jump to conclusions. Sometimes it is permissible to “shoot from the hip,” so to speak. For example, you may observe hundreds of Japanese beetles feeding on the foliage and flowers of vegetables and ornamental plants in your yard. Later, when someone calls and says that shiny beetles are eating “everything” in the yard you may correctly conclude that these clients are also being pestered by Japanese beetles. On the other hand, a caller may complain about “fluffy white stuff‘ on a plant; in this case the problem could be mealybugs or woolly aphids but might also be planthoppers. In such cases you need to follow a logical process of diagnosis: get some facts before jumping to conclusions; narrow down the possibilities systematically. G E T l N G THE FACTS. In most cases you can gather

facts by telephone or at plant clinics. Most people inquire about insect pests by phone. This method is easiest for the caller but makes accurate diagnosis difficult. Telephone inquiries generally fall into three categories:

1 . The caller seems to recognize the pest and just wants advice on control. Sometimes the caller can correctly identify the problem. In this case the caller is usually satisfied if you give specific control information from the North Carolina Agricultural Chemicals Manual. Other times the caller cannot identify the problem correctly. People often read about garden pests in magazines and books but are apt to get insects and mites mixed up because they are so small that accurate identification is difficult. If intuition tells you the caller is mixed up (for example, the caller describes “flying mites” or “webspinning aphids”), ask for more information. 2. The caller does not know what the pest is but can identijSI the plant being attacked. This is a good situation because this client does not have a preconceived idea about the pest, which might throw you off the track. Also,

because the caller can identify the plant, you can proceed to the section, “Narrowing Down the Possibilities.”

3. The caller does not recognize the pest or the plant. This situation presents the greatest challenge. You can narrow down the number of possible pests in several ways. By asking appropriate questions, you may be able to pinpoint the plant and the identity of the pest. You can then make a control recommendation. However, should the identity of both plant and pest defy these attempts, you have three more logical choices. A. You can guess the identities and make a recommendation. In addition to being unethical, this approach is risky because a blind guess is likely to be wrong. B. You can ask the client to bring in samples of the pest and the plant f o r the Extension agent to identify. Those clients who are seriously interested in identifying the pest will take the time to collect samples and bring them to the Extension office.

C. You can refer the client to the Extension agent. You should not regard this course of action as defeat; it is the expected procedure. In addition to gathering information by phone, Master Gardeners sometimes conduct plant clinics and may encounter all types of plant diseases and insects. Plant clinics are much better than telephone calls for gathering information about pest problems. You can not only identify the plant with greater certainty, but you can often scrutinize the pest as well. Most county plant clinics have a stereoscope or at least a hand lens for close observation of the pests. Furthermore, you can get help from fellow Master Gardeners in making or confirming your diagnosis. The old saying, “Two heads are better than one,” is especially true at plant clinics. By pooling your knowledge with that of others, you can bring additional expertise and diagnostic skills to bear on problems.

Narrowing Down the Possibilities It is estimated that there are about one million identified insect species. Fortunately, many are not pests of ornamental plants and turfgrass, and many do not occur in North Carolina. An estimated 1,700 species of insects and mites are pests of ornamentals and turf in North Carolina -still a formidable number. Indices, keys, and pest calendars can help you to narrow down the possibilities when identifying a pest. INDICES. Pests are often indexed in two ways in pest publications: by name and by host plant. Cynthia Westcott’s The Gardener’s Bug Book, has one of the more complete pest indices by host plant. North Carolina Agricultural Extension Service publication AG- 189,

Master Gardener Insect Guide

Insect and Related Pests of Shrubs, also has an index to pests by host plants. If the host plant is known, using the indices narrows down the list of 1,700 possible pests to 20 or so pests of a particular plant. Through further questions to the caller about the size, shape, damage, and secretions of a pest, you can narrow the list down to four or five possibilities. Based on this information, your experience, and the reference material at hand, you may be able to identify the pest and suggest a control method.

In addition to pest indices (or better, in conjunction with the use of indices), keys provide another method of narrowing down the list of possible pests. KEYS. Keys are an organized series of choices that can open the door of knowledge about any subject. Extension publications AG-189 and AG-268 contain introductory keys to pest identification on the family level (for example, lady beetles belong to one family, lightning bugs to another, and all weevils to yet another family). By keying a pest to family and using the indices of pests by host plant, you can usually identify a pest species correctly. Furthermore, AG-268, Insect and Others Pests of Tud has a key to turf pest damage. Thus, two kinds of keys and the indices in AG-268 and the host plant index in The Gardener’s Bug Book can be consulted to identify the turfgrass pest. This guide has a key to “Signs and Symptoms of Insect, Mite, and Slug Pests of Ornamental Plants,” which may also be helpful in diagnosing plant pest problems.

many aphids and other pests, and each lady beetle lays many eggs that hatch into many more larvae. Each pupa destroyed allows thousands of aphids to survive. SEEDCORN MAGGOT FLIES. Each spring home gardeners discover dead flies on the tips of dogwood and crape myrtle twigs (Figure 2). These flies are infested with an Entomophthora fungus, which “programs” the fly to land on a prominent perch (such as a dead twig) to die. Then the fungus fruits (sporulates) and the spores disperse to infect other flies. The fungus is beneficial because it attacks seedcorn maggots, which consume the inside of seeds, forcing many gardeners to replant. Because the unfortunate flies often select bare twigs on which to make their last landing, home gardeners may jump to the conclusion that the fly is harming the twig. This is a reasonable mistake and it happens often.

Figure 1. Lady beetle pupa.

CALENDARS. Many pests are associated with turf and ornamental plants only at certain times of the year. When confronted with an unknown lawn pest, for example, you can consult the “Turfgrass Pest Control Calendar” in the last section of this guide. For example, suppose it is July and the pest appears to be an immature insect. According to the “Turfgrass Pest Control Calendar,” white grubs are usually not a pest in July; thus this possibility can be eliminated.

Common Mistakes in Pest Diagnosis If all ornamental plant pests were always in the most easily identified stage, diagnosis would be a breeze. However, all 1,700 potential pests of ornamentals in North Carolina have egg stages and immature stages that may be difficult to identify. Following are four examples of common mistakes. LADY BEETLE PUPAE. The pupae of lady beetles attach themselves by the hind end to leaves or twigs (Figure 1). Because these pupae do not particularly resemble adult lady beetles the home gardener who finds these pupae on a plant might assume that they are “sucking the life” out of the plant. Consequently, the pupae are destroyed. How unfortunate! Each lady beetle larva eats

Figure 2. Adults of seedcorn maggot on twigs where they died from an €nfomophfhofa fungus.

KEYS TO SIGNS AND SYMPTOMS OF SOME INSECT, MITE, AND SLUG PESTS

OSMOCOTE PELLETS. Slow-release fertilizers are

sometimes formulated with a resin coat, which allows the fertilizer to be released slowly. When most of the fertilizer in a pellet has been released, the pellet becomes transparent and swollen to about the size of a slug egg. Slug eggs are, indeed, transparent at one stage of development, but slug eggs are sticky, and moist and usually laid in batches with the eggs stuck together. Fertilizer pellets are not sticky. Some insect eggs are about the size of fertilizer pellets, but insect eggs are not transparent (translucent sometimes, more often opaque). Pity the gardener who spends hours picking the “eggs” out of the potting mix after purchasing plants treated with a slow-release fertilizer.

OXALIS SEEDS. Oxalis, or yellow wood-sorrel (Oxalis strictu) commonly occurs in greenhouses and nurseries in North Carolina. This small plant has a seed capsule that

Figure 3. Oxalis seeds.

dehisces explosively, throwing the seeds for several feet. The seeds are reddish brown and sometimes adhere to the leaves of potted plants in a most insectlike manner (Figure 3). Because scales and mealybugs often settle down to feed in a manner that hides the legs, antennae, and mouthparts, oxalis seeds are often mistaken for scales.

KEYS TO SIGNS AND SYMPTOMS OF SOME INSECT, MITE, AND SLUG PESTS he following is a key to signs and symptoms of insect pests of ornamental plants (but not turf;publication AG-268 contains a key to turfpest damage). Various kinds of insects and other pests cause plant injury that looks similar or sounds similar when described over the phone. This key will help you distinguish the various pests and thus make more effective pesticide recommendations. It includes the more common pests and the more common symptoms of injury. You will no doubt encounter many other pests that will not progress easily through this key. In that case, proceed to indices of plant pests listed by host plants (Westcott, AG-189, AG-268).

A key is a device that unlocks something. Entomologists use keys to unlock the door to the identity of an unknown insect or mite. The following key is a series of couplets that offer you a choice. Start at couplet 1. Is the pest chewing the plant tissue? If so, proceed to couplet 16, where you are confronted with another pair of choices. On

Couplet No.

the other hand, if the pest is feeding but not chewing away chunks of plant tissue, then proceed to couplet 2 where again your are given another choice. By proceeding through the couplets and making this series of choices, you will eventually arrive at a couplet that will help you identify the pest. Do not be discouraged if you find it difficult to use the key; entomologists often joke that the only person who can effectively use a key is the person who wrote it! Generally, insects in the adult stages are the most easily keyed out (especially winged insects). However, it is not always easy to tell if a wingless pest is adult or immature. The following truisms may-helpto decide: If a pest has wings, it is an adult insect.

W If a pest is mating, laying eggs, or giving birth to young, it is in the adult stage.

Refer To.

Description

Pest chewing away plant tissue

..........................................................................

Pest feeding on plant (usually through a jointed beak) but not chewing away plant tissue ................................................................................................ Pest excreting honeydew, infested plant sometimes becomes sticky and wet looking, sometimes becomes dark with sooty molds ...................................... Pest not excreting honeydew; plant not sticky, not wet

........................................

..

b Couplet 16

b Couplet 2 b Couplet 3 b Couplet 12

Master Gardener Insect Guide

Couplet No.

Refer To.

Description

Plant disfigured by white, fluffy residue or white, sticky residue secreted by pest ..........................................................................

............................................................ Insect covered with fluffy residue jumps when disturbed ....................................

Plant does not have white, fluffy residue

..

b Couplet 4 b Couplet 10 b Flatid Planthopper p. 11

Insect covered with fluffy residue or sticky residue; does not jump when disturbed .................................................................................................. Insect covered with sticky, white residue

............................................................

b Couplet 5 b Wax Scale p. 13

Insect covered with white, fluffy residue On leaves of silver maple

............................................................

..................................................................................

b Couplet 6 b Woolly Alder Aphid p. 12

Not on leaves of silver maple ..............................................................................

b Couplet 7

On stems of apple, crabapple, or pyracantha ......................................................

b Woolly Apple Aphid p. 12

Not on stems of apple, crabapple, or pyracantha ................................................ Insect inside the cupped, terminal leaves of boxwood

........................................

b Couplet 8

b Boxwood Psyllid p. 11

Insect not on boxwood........................................................................................

b Couplet 9

On house plants; sometimes on shrubs in yard. ..................................................

b Mealybugs p. 13

On shrubs and trees in yard

..............................................................................

b Soft Scales p. 13

Insect small with fragile legs; usually a few animals in the group with wings; abdomen with a pair of “exhaust pipes” (cornicles) ............................................

b Aphids p. 12

Insect has inconspicuous legs, usually no wings, no “exhaust pipes”

.................. b Couplet 11

Insect very small; feeding on lower surface of leaf only; sometimes accompanied by tiny whiteflies ............................................................................

b Whiteflies p. 12

Insect small; feeding on leaves and stems; without tiny white flies ......................

b Soft Scales p. 13

Plant injury consists of small but distinct, pale spots ............................................ Plant injury not small, distinct, pale spots ............................................................

b Couplet 13 b Couplet 15

Insect a small, dark, spiny animal or lacy animal feeding on lower leaf surface; upper surface of leaf with pale spots ..................................................................

b Lace Bugs

Pest not as above

..............................................................................................

P. 9 b Couplet 14

KEYS TO SIGNS AND SYMPTOMS OF SOME INSECT, MITE, AND SLUG PESTS

Couplet No.

Refer To. ..

Description

Pest pale green, long, narrow; runs sideways when disturbed ..............................

b Leafhopper p. 10

Pest tiny, eight legs, sometimes spins conspicuous webbing ................................

b Spider Mites p. 25

Insect covered with white, fluffy residue; insect on bark of pines, especially white pine .....................................................

........ b Pine Bark Adelgid p. 11

Insect covered with firm crust that can be flaked off to expose naked body of insect.....................................

....................

b Armored Scales p. 14

I I\

Webbing associated with pest .........................................................................

b Couplet 17

Webbing not associated with pest ........................................................................

b Couplet18

Caterpillars form dense, white “tents” in crotches of trees in spring; tents usually seen in wild cherry, crabapple, and related trees..........

........ b Eastern Tent Caterpillar p. 19

Caterpillars form loose webs at ends of branches in summer .....

........ b Fall Webworm p. 19

Slime trails usually associated with damage to succulent plants in spring ............ b Slugs p. 26 Slime trails not associated with damage

........

Leaf margin chewed ............................................

........ b Couplet 19 .....................................

Leaf injured away from margin ............................................................................ Injury occurs at night ........................

............

.....................................

b Couplet 20 b Couplet 21 b Weevils p. 15

Injury occurs during day ......................................

Leaf skeletonized at night only

..................

............................

.............. b

Caterpillars p. 17-21 b Grasshoppers P. 7 b Japanese Weevils p. 15

........ b Chafer Beetles p. 15

Leaf skeletonized during day or day and night ......................................................

b Couplet 22

Appears in elm trees; small grubs and beetles feeding together during day ..........

b

Elm Leaf Beetle p. 15

b Larger Elm Leaf Beetle p. 15 \ Appears on various trees; small, metallic green beetles with shiny brown backs and white spots on sides ............

...............................

b Japanese Beetle p. 15

Master Gardener Insect Guide

Sooty Molds on Ornamentals Sooty molds are dark fungi that grow in honeydew. Honeydew is a sweet, sticky liquid excreted by insects that feed from the phloem tissue of plants on sap that they suck through slender, threadlike mouthparts. Aphids, mealybugs, soft scales, and planthoppers all feed this way. Sap from the phloem tissue is rich in sugar but poor in other nutrients needed by the sucking pest. These insects consume copious amounts of sap to get enough minor nutrients and therefore must excrete copious amounts of sweet, sticky honeydew. Unless washed off by rain, honeydew clings to the plant and objects below it. Spores or fragments of sooty molds are blown or carried to the honeydew, and new colonies of sooty molds develop. Many times the tiny strands of sooty molds become so abundant that infested plants appear dark and sooty or almost charcoal gray. Sunlight is shaded out to the point that photosynthesis is no longer possible. Heavily infested leaves often die. Feeding by a large number of aphids or scales combined with the heavy coating of sooty molds may drastically reduce the vigor and beauty of ornamental plants. Although the fungal strands of sooty molds do not parasitize plant tissue, they often cling tightly to the surface. Even after the source of honeydew is eliminated, sooty molds may adhere to plants and other objects for months. The first step in the control of sooty molds is to control the aphid, scale, or other pest excreting honeydew. It is advantageous to use horticultural oil to control the insect pest, because oils loosen sooty molds from the plant and hasten the weathering away of the fungi. (Horticultural oils are formulated by many companies and are available from garden centers, hardware stores, and nurseries.)

Detecting and Monitoring Insect Pests of Turfgrass Fortunately, most of the insects found in turf are not damaging. Those that damage grass, however, often escape detection until serious damage has occurred. Some insects feed on the plant roots, and others chew on leaves and suck plant juices. The following techniques can be suggested to home gardeners who are concerned with turf problems. Suggestions are made to help you decide when enough pests are present to warrant pesticide treatment. CHINCH BUGS. Insert a large metal can with both ends cut out (other similar objects will work) into the turf in an area where the mass is vellowed and declining. Fill the Y

can with water. Wait five minutes for the chinch bugs to float to the top of the water. Examine three or four places in the suspected area. Parting the grass to observe the soil surface for chinch bugs also works. (The experienced gardener may identify chinch bugs by odor.) Treat if an average of 20 or more chinch bugs per square foot are found. SOD WEBWORMS, MOLE CRICKETS, ARMYWORMS, AND OTHER CATERPILLARS.

Mark off a 1-square yard area in a location of suspected infestations. Mix 2 ounces of liquid dishwashing soap in 4 gallons of water and drench the area with the solution. Insects will emerge to the grass surface. Observe the area closely. Insects will return to the soil in 5 or 10 minutes. If no insects are found, examine other suspected areas. Treat if (1) an average of 40 or more sod webworms are found per square yard, (2) an average of three or more mole crickets are found per square yard, or (3) an average of eight or more caterpillars are found per square yard. WHITE GRUBS. At the edge of an off-color area in the turf, cut three sides of a 1-square-foot piece of sod about 3 inches deep. Pull or pry the sod back like a flap; examine roots for chewed-off remnants and check the soil for grubs. Using your fingers, sift through the soil and roots. Treat if three or four grubs are found per square foot. OTHER INSECTS. Closely examine turf for evidence of damage by other insect pests (ants, bees, wasps, and leafhoppers). Always check the turf where the damaged area meets the green, healthy grass. That is where the insect pests will most likely be the most abundant.

INSECTS, MITES, AND OTHER PESTS

What Are Insects? Insects are animals, which in the adult stage, have three pairs of jointed legs (Figure 4). Most insects are smaller than house flies; many are extraordinarily small. Some adult insects have wings, whereas others do not. Many insects are familiar: flies, fleas, caterpillars, moths, butterflies, grasshoppers, stink bugs, dragonflies, and many others. An estimated 1,700 species of insects, mites, and other pests feed on ornamental plants and turfgrasses in North Carolina. In the following section, insects are grouped in orders and families or groups of families within orders.

Grasshoppers and Mole Crickets (0rthopte ra) Insects in the order Orthoptera have mouthparts for chewing. The young generally feed in the same place and on the same food as do adults. The wings of adults are leathery and have many veins. Two families, grasshoppers and mole crickets, are the most important orthopteran plant pests.

t-y Figure 4. Typical insect showing six legs with joints.

SHORTHORNED GRASSHOPPERS (Figure 5 ) . Some

grasshoppers are fairly large insects (up to about 2 inches long) and are fairly slender. The hind legs are long and enlarged for jumping. The forewings are narrow, tough, and leathery, and they form a protective covering for the hind wings when the grasshopper is not flying. Grasshoppers chew on the leaves and flowers of a variety of grasses and ornamental plants as well as field crops and weeds. The shorthomed grasshoppers of North America are very similar to the locusts of the Old World (the locusts that John the Baptist ate were grasshoppers, not locust trees or cicadas). Fortunately, grasshoppers are not usually a plague for the modem home gardener; they are susceptible to a variety of commonly used insecticides.

Figure 5. Shorthorned grasshopper laying eggs.

MOLE CRICKETS (Figure 6). Mole crickets are turfgrass pests adapted for digging just below the soil surface. In addition to feeding on the roots of numerous grass species, this digging makes them a real threat to turf. Preferring sandy soils, mole crickets tunnel 3 to 4 feet in a single night. As the mole cricket tunnels along, it pushes up a small ridge. Extensive tunneling loosens and dries out the soil, causing moisture stress, and the crickets’ feeding prunes roots. Closely mowing golf greens scalps the grass off of the tunnel ridge. Mole crickets have one generation per year, with young nymphs feeding voraciously in August through October. The following spring, they soon become adults and begin laying eggs for the next generation in midsummer. Figure 6. Mole crickets; (a) adult, (be) nymphs.

\

/

\I

Master Gardener Insect Guide

BARKLICE (Psocoptera). Barklice are small, fragile insects that feed on mildews, molds, and other organic debris (Figure 7). The young hatch from eggs and gradually develop through a series of molts into adults. Our most conspicuous barklouse is Psocus venosus, a gregarious species often noticed in “herds” on the bark of crape myrtles and other ornamentals. Some species of barklice reside under silk webbing that they spin. Home gardeners may become concerned about the appearance of trees webbed by barklice. Barklice affect only the appearance, and they can easily be dispersed by a strong stream of water from the garden hose.

Figure 7. Adults and nymphs of the barklouse, Psocus venosus.

I

THRIPS (Thysanoptera). Thrips that attack plants are extremely small (at most V16 inch long, Figure 8). These parasites suck the plant juice from the surface of leaves and petals. The most abundant thrips, the flower thrips, breeds in trees, shrubs, flowers, and weeds. Two noticeable flights usually occur in late May and late August. Flower thrips wedge into rose buds (and other flower buds) and feed on the expanding petals; they are particularly attracted to white or pale flowers. By the time the buds open, the beauty of the flower may already be ruined. In the landscape, thrips are generally susceptible to pesticides, but flowers may have to be sprayed every two to three days during the flights to obtain good control because of the huge number of thrips migrating from surrounding areas.

Bugs, Aphids, Scales, and Others (Hemiptera) Insects in the order Hemiptera all have mouthparts adapted for piercing into a plant or animal and sucking out sap, plant juice, or blood (Figure 9). The mouthparts are long, slender, threadlike structures containing two channels. As these insects insert their mouthparts into a plant, they secrete saliva through one of the channels. For most Hemiptera, the saliva merely lubricates the mouthparts so less effort is needed to penetrate the host tissue. When the desired tissue is found, these insects suck sap or juice out of the plant through the other channel.

(tubelike)

Figure 9. Close-up of front end of a bug showing the tubelike mouthparts.

The saliva of some sucking insects is very toxic to some plants; heavily infested plants decline rapidly and may die. Lace bugs have such a potent saliva that tissue in the area around the mouthparts is predigested, and the lace bug is able to suck the contents from several adjacent cells at once, leaving a conspicuous pale spot on the leaf. Immature Hemiptera are called nymphs (they hatch from eggs). The nymphs usually feed at the same site and in the same manner as the adults. (Some aphids and scales give birth to nymphs.)



1

3

INSECTS, MITES, AND OTHER PESTS

SCENTLESS PLANT BUGS (Figure 10). The boxelder bug is the most common scentless plant bug. Boxelder bugs do not cause noticeable damage to landscape plants and do not bite humans. These gray and orange insects are a nuisance when they congregate on landscape plants and dwellings. They enter houses through cracks and crevices to overwinter. They have been reported on dozens of kinds of plants, but they prefer maple trees (especially female boxelders) as their host plant. Enormous numbers develop on the seeds of boxelder trees. For long-term control of boxelder bugs, you must cut down the female boxelder trees. If homeowners desire boxelders in their landscape, they should plant male trees. PLANT BUGS (Figure 11). The tarnished plant bug feeds on a wide variety of vegetable and ornamental plants. If fed upon by tarnished plant bugs, young tissue often fails to develop normally, and damaged buds produce misshapen flowers. LACE BUGS (Figure 12). These small, lacy bugs feed on the lower surface of leaves, but their saliva is so toxic that it causes pale spots on the upper surface. Heavily infested plants may appear to be totally bleached out. Lace bugs insert their eggs into the lower leaf surface. When the nymphs hatch, they usually feed in groups and are often protected by their mother. Lace bugs deposit varnishlike excrement (“fly specks”) on the lower surface of leaves. The three major lace bug pests in North Carolina are azalea lace bugs (on azaleas and rhododendrons), hawthorn lace bugs (on hawthorns and pyracanthas), and sycamore lace bugs on sycamore trees. Lace bugs produce at least two generations per year in North Carolina. LYGAEID BUGS (Figure 13). The chinch bug is the major lygaeid pest in North Carolina; it feeds primarily on Saint Augustinegrass. These tiny bugs (1/16 inch long) occasionally cause heavily infested turf to turn brown in warm weather. Adult chinch bugs overwinter in sheltered habitats and emerge in spring to lay eggs. The adult bugs are black with white markings; the small nymphs are bright red. d

Figure 10. Boxelder bug; (a) adult, (b) eggs, (c-f) nymphs.

Figure 11. Tarnished plant bug; (a) adult, (be) nymphs.

e a a

Figure 13. Chinch bug; (a) adult, (b) eggs, (c-g) nvmDhs. I

.

Figure 12. Azalea lace (c-e) nymphs.

Master Gardener Insect Guide

CICADAS (Figure 14). These noisy insects, which leave their empty “shells” clinging to tree trunks, are also known as harvestflies and locusts. Cicadas damage shade trees and fruit trees when the female splits open twigs to lay eggs in the wood. The twigs die and droop before breaking off completely. The tiny nymphs hatch, drop to the soil, and dig to feed on roots. Cicada nymphs may develop in as little as two years (dogday cicada) or as many as 13 or 17 years (periodical cicadas). Adult cicadas are 1 to 2 inches long. SPllTLEBUGS (Figure 15). Immature spittlebugs

secrete a bubbly liquid in which they reside (Figure 15C). Adult spittlebugs are sometimes called froghoppers because some species vaguely resemble small frogs (l/4 inch) and because they jump readily. Twolined spittlebug nymphs breed on turf,especially in areas of dense growth and heavy thatch, but adults often fly to hollies. When fed upon by spittlebugs, Japanese hollies may defoliate, and American hollies may develop large yellow spots on the leaves. Nymphs of the pine spittlebug often produce copious amounts of spittle on pine stems.

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LEAFHOPPERS (Figure 16). Leafhoppers are usually small, slender insects that readily jump and fly. They are attracted to light. Leafhoppers also bite people, but it is usually not very painful and there are no lasting effects. Adults and nymphs usually run sideways when disturbed. Perhaps because of their small size and rapid motion, leafhoppers are rarely submitted for determination. Leafhoppers damage marigolds and dogwoods in the same way lace bugs do (producing chlorotic spots on the upper leaf surface). Often the white, empty nymphal skins are left on the lower surface. New lawns may be seriously damaged by leafhoppers, making reseeding necessary. There are many species of leafhoppers, and some are important pests of agronomic crops.

Figure 14. Cicada; (a) adult, (b) a hardwood twig split to show inserted cicada eggs, (c) shell of cicada nymph after the adult has emerged.

P Figure 15. Twolined spittlebug; (a) adult, (b) nymph, (c) spittle formed by nymph.

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Figure 16. Potato leafhopper; (a) and (b) adults, (c) egg, (d-h) nymphs.

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INSECTS, MITES, AND OTHER PESTS

FLATID PLANTHOPPERS (Figure 17). The citrus flatid planthopper is our most common flatid. Nymphs feed through the bark of twigs and suck sap from the phloem. As they feed, they excrete honeydew and secrete a white, fluffy wax that completely hides the insects and forms a “nest” around each one. Adult citrus flatid planthoppers resemble husky, overgrown, grayspotted leafhoppers. Most homeowners are concerned with the nymphs and probably never notice the adults. Except for disfiguring infested plants with their honeydew and fluffy wax, these planthoppers do not cause serious plant problems. PSYLLIDS AND JUMPING PLANTLICE (Figure 18). These insects are much like the flatid planthoppers: adults and nymphs suck sap from the phloem and excrete honeydew. Nymphs of some species secrete wax. Furthermore, some psyllids form galls (for example, the boxwood psyllid and hackberry gall psyllid). Adult psyllids resemble leafhoppers with clear wings. They lay eggs on the leaf surface (persimmon psyllid) or insert them between the bud scales (boxwood psyllid). PHYLLOXERA AND ADELGIDS (Figures 19 and 20). Ornamental plant pests in this family are found on two kinds of trees: phylloxera in galls on hickories and pecan (Curya ) and adelgids on the bark of conifers. Phylloxera on Carya form large galls on leaves and petioles in the early spring. By late spring, the galls have matured and the phylloxera crawl out to lay eggs on the twigs to overwinter. These eggs hatch the following spring just as the buds break. The most common adelgid is the pine bark adelgid of white pine, which becomes abundant in late winter. Lady beetles and other predacious insects quickly consume most of the adelgids as soon as the temperature rises so the fluffy white residue secreted by the aphids and detritus left by the adelgids and predators are all that remain on the bark. Some adelgids cause spectacular galls on spruces.

a Figure 17. Citrus flatid planthopper; (a) adult, (b) nymph with white, fluffy filaments removed to show pale green body and red eyes.

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Figure 18. Box( woods psyllid; (a) adult, (b) egg, (c) nymph, (d) damage.

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Figure 20. Pine bark adelgid; (a) adult surrounded by eggs, (b) nymph, (c) infested white pine twig.

Figure 19. Phylloxera; (a) adult, (b) eggs, (c-e) nymphs,

(9 phylloxera galls on pecan leaf.

Master Gardener Insect Guide

APHIDS AND PLANT LICE (Figure 21). Aphids are

Figure 21. Aphids; (a) adult, (b) nymph, (c) infested crabapple shoot.

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Sooty Mold

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Wooly Alder

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Figure 22. Silver maple leaves infested with wooly alder aphids.

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small, soft, fragile insects that feed in the phloem by sucking out sap. Aphids sometimes excrete copious amounts of honeydew. During the growing season, most aphids reproduce by giving birth to live young (nymphs). Most species have a fall generation of males and females that mate, and the females then lay overwintering eggs. Aphids often have complicated life cycles. Some develop into wingless females. Others develop wings as adults. Some species alternate from one host to another. In some species (such as the green peach aphid, rose aphid, and potato aphid), aphids have a characteristic pair of tubelike cornicles on the rear of the abdomen, resembling the dual exhaust pipes of a hotrod. Other species may have very short cornicles (such as Cinaru aphids on pine). A large number of predacious and parasitic insects feed on aphids and sometimes cause populations to decline rapidly. Nevertheless, from time to time aphids in one locality may “escape” predators. Excessive feeding and sooty molds growing in honeydew excreted by the aphids can severely damage trees and shrubs. WOOLLY APHIDS (Figure 22). These insects resemble

aphids but lack tubelike cornicles. Wooly aphids have many glands that secrete fluffy, white wax. The woolly apple aphid feeds on the roots of apple trees, crabapple trees, quinces, and pyracanthas. Woolly apple aphids overwinter as eggs on elm trees and as other stages on roots and in scars and pruning cuts on apple trees. In spring, the eggs hatch and the woolly aphids form galls on the elm leaves. The next generation of woolly apple aphids fly from elm back to apple, and so on. Woolly alder aphids overwinter as eggs on soft maples, especially silver maple. In spring, woolly alder aphids infest maple leaves, reproduce, excrete honeydew, secrete wax, and become a genuine nuisance on yard trees. In late May and early June, woolly alder aphids begin to fly to alders and reproduce there all summer until males and migratory females develop in early fall. After mating, these females seek out maples and lay eggs on the bark for the next year’s generation. WHITEFLIES (Figure 23). There are about 1,100species

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Figure 23. Greenhouse whitefly; (a) adults, (b) eggs, @-e) nymphs, (9pupa.

of whiteflies in the world, but only three are a real nuisance in North Carolina: greenhouse whiteflies, sweetpotato whiteflies, and citrus whiteflies. Greenhouse whiteflies and sweetpotato whiteflies infest herbaceous ornamentals and vegetables. These species cannot overwinter outdoors in North Carolina. Gardeners should purchase bedding plants that are free of whiteflies because the both greenhouse whitefly and sweetpotato whitefly are resistant to many insecticides and are extremely difficult to control. The citrus whitefly is a pest of gardenias and can survive the winter as long as the gardenias survive. All whiteflies feed in the phloem and excrete honeydew in which sooty molds often grow. Heavily infested plants may die. I,

INSECTS, MITES, AND OTHER PESTS

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SOFT SCALES (Figure 24). All female scale insects lack wings. Because female scales molt once less often than male scales, it is thought that scales evolved to the state in which last-stage female nymphs lay eggs after mating with fully developed males. Because female scales lack wings, they can reach new plants only by being carried or by crawling. Females usually lay eggs from which “crawlers” hatch. These tiny insects seek out a suitable feeding site, insert their mouthparts into the phloem, and suck sap. They molt as they grow. Some soft scales can crawl as they develop, but others have only two mobile stages: crawlers and males. Wax scales lack a male gender and only crawlers can move about. Cottony maple leaf scales can crawl as early- and late-stage nymphs, and as females as well as males. Some scales (such as the hemispherical scale) protect their eggs under the mother’s body. The brown soft scale lays eggs that hatch immediately. Cottony maple leaf scales and cottony camellia scales lay up to 1,500 eggs per female in a dense, fluffy mass of white wax called an ovisac. MEALYBUGS (Figure 25). Most plant lovers are aware of the white, mealy wax, copious honeydew, and the toxic effect that mealybug feeding has on ornamental plants. Mealybugs resemble soft scales in biology. Eggs are laid in a loose (or dense) ovisac. Females are wingless and molt once less often than males. Some species (such as the longtailed mealybug) give birth to live young. Some species have long, white “tails” and others are almost bare. The citrus mealybug is the most common and damaging species and is the most difficult to control. Fortunately, citrus mealybugs are found only on house plants in North Carolina.

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Figure 24. Soft scales; (a) brown soft scale, (b) hemispherical scale, (c) wax scale; (d) cottony maple leaf scale.

Figure 25. Citrus mealybug; (a) female, (b) male, (c) eggs, (d-h) nymphs, (i) damage on Polyscias plant.

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Master Gardener Insect Guide

rRMORED SCALES (Figure 26). Armored scales are so

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amed because of the armor (a varnishlike covering called le test), which protects the bodies of nymphs and female :ales. (Male armored scales are tiny gnatlike insects iuch like the males of soft scales and mealybugs.) Most :male armored scales lay eggs inside the armor, but some Jecies give birth to live crawlers. Some armored scales ;uch as the tea scale and the camellia scale) cause spots n the host plant leaves, and some (such as the peony :ale and obscure scale) cause twig and limb dieback. mored scales are somewhat protected from synthetic pesticides by the test, but horticultural oils are effective for control.

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GROUND PEARLS AND COlTONY CUSHION SCALES (Figure 27). The family Margarodidae includes

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a number of exotic species with bizarre habits. Some margarodid scales in Australia grow up to an inch long! Cottony cushion scales probably originated in Australia and have been introduced on citrus plants onto every continent. Some of the Central American ground pearls are large and showy enough that natives actually string them as beads. Cottony cushion scales are occasional pests of pittosporum and nandina in North Carolina. These scales lay their eggs in dense, fluffy, white masses called ovisacs. Cottony cushion scales suck sap and secrete honeydew. Heavily infested pittosporum shrubs turn black with sooty molds and often die.

Figure 26. Armored scales; (a-d) gloomy scale, (a) female (b) large male, (c) male, (d) crawlers, (e) fern scale. White, slender scales are large male nymphs. Dark wide scale is female; (f-h) tea scale, (9 female, (9) male, (h) crawler.

In North Carolina, ground pearls are occasional but serious pests of centipedegrass and other warm season grasses. Feeding on the roots turns the grass yellow. Badly infested turf usually dies during winter, resulting in irregularly shaped bare patches that are invaded by several weeds in the following spring. Unfortunately, there are no effective control practices other than maintaining a healthy turf.

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Figure 27. Margarodid scales; (a-g) cottony cushion scale, (a) female, (b) eggs, (c) crawler, (d) nymph with wax, (e) newly molted nymph, (9 male, (9) damage to pittosporum, (h) portion of turf infested with ground pearls.

INSECTS, MITES, AND OTHER PESTS

Beetles (Coleoptera) Many kinds of beetles are familiar insects. Ladybirds and ladybugs are beetles in the lady beetle family. Weevils, chafers, flea beetles, white grubs, glowworms, lightning bugs, and sawyers are all beetles. On spring or summer nights when a porch light is left on, bark beetles, May beetles, June beetles, ground beetles, and other insects are attracted to the light. Most beetles reproduce by laying eggs from which hatch larvae. Beetle larvae usually feed and develop in a habitat different from that of the adult beetle. Beetle larvae molt into a developmental stage called a pupa. From these pupae emerge adult beetles. Because they are often in the soil or inside bark or wood, beetle larvae are not observed as frequently as adults. Consequently, home gardeners often think that big beetles grow from little beetles. They do not. Once a beetle emerges from the pupa, it does not molt again or grow any larger. Beetle larvae and adults also have mouthparts for chewing. Five families of beetles are common pests of ornamentals and turf. CHAFERS AND WHITE GRUBS. (Figure 28) Chafers are scarab beetles, which chew away flower petals and the upper surface of foliage, leaving a delicate skeleton of veins behind. This sort of feeding is called chafing or skeletonizing. Some of these beetles fly at night (for example, May beetles, June beetles, and Asiatic garden beetles) and some during the day (the Japanese beetle and green June beetle). In the immature stages of chafer beetles, white grubs usually feed on the roots of turfgrass and ornamental plants. Many grubs remain in the soil as long as three years. Sometimes white grubs are abundant enough to cause significant damage to turf, but they are often not noticed until birds, skunks, and moles destroy the turf searching for them or until the turf dies out in dry weather. Heavy grub infestations destroy grass roots, causing the area to become “springy” and allowing the turf to be rolled back like a carpet. Some species of grubs emerge from the ground and crawl around. Green June beetle grubs may be identified by the unusual habit of crawling on their backs.

Figure 28. Chafer beetle; (a) adult (b) grub.

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Figure 29. Weevils; (a) Japanese weevil (b) weevil grub.

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WEEVILS AND BILLBUGS (Figure 29). Weevils are

less common than chafers but are sometimes devastating pests of ornamental plants. Weevils develop through egg, grub, pupa, and adult stages. The grub stage of most ornamental pest weevils develops in the soil and feeds on roots, although the grubs of the white pine weevil develop inside the topmost twig of white pines. Most weevil pestsof ornamentals feed at night and hide during the day, but the Japanese weevil feeds in broad daylight. Grubs of certain billbugs feed on the roots and burrow in the stems of some varieties of turfgrass. Adults feed on stems and leaves.

Figure 30. Elm leaf beetle; (a) adult, (b) eggs, (c) larva, (d) pupa, (e) damage by adult (left) and larva.

LEAF BEETLES (Figure 0). Some leaf beet es are unusual among the beetles in that the larvae and adults both feed on leaves of ornamental plants. The larvae tend to skeletonize leaves, whereas adults chew holes in leaves as they feed. The egg and pupal stages are usually found on the foliage, although the biology of leaf beetles varies with species.

Master Gardener Insect Guide

LONGHORNED BEETLES AND ROUNDHEADED BORERS (Figure 32). Longhomed beetles are named

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because of their long, conspicuous antennae. Most longhorned beetles lay their eggs on dead or declining trees. The tiny larvae that hatch bore into the cambium or wood. They are usually slender, white, round, legless insects with brown heads and are called roundheaded borers. Recently killed pines and fresh pine logs are often infested with roundheaded borers called sawyers.

Figure 31. Bark beetles; (a) adult, (b) larva, (c) galleries or engravings in cambium.

Sawyers make an audible squeaking or creaking noise as they feed. You can hear the larval sawyers working in a tree from a distance of several feet. (Bark beetle larvae are too small to make a noticeable noise inside an infested tree.) Some longhorned beetles (such as the azalea stem borer and dogwood twig borer) fly to twigs and chew a double row of holes in the bark. They insert an egg between the rows, and the newly hatched roundheaded borer tunnels down inside, killing or weakening the stem. LADY BEETLES (Figure 33). Also called ladybirds and ladybugs, lady beetles are regarded with more popular affection than any other beetle. Lady beetles (except for the Mexican bean beetle and the squash beetle) feed on plant pests. Eggs are laid near aphids, scale insects, or spider mites. After hatching, the tiny lady beetle larvae feed on nearby plant pests. The larvae molt several times as they grow. Finally, the last stage larva fastens itself by the rear end to a leaf or twig and then pupates. The pupae develop for several days; then new lady beetles emerge from the pupal stages.

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b Figure 32. Longhorned beetles; (a) dogwood twig borer adult, (b) dogwood twig borer larva.

BARK BEETLES (Figure 3 1). Bark beetles usually develop in trees that are under stress. Adults fly to declining trees and chew into the cambium, where they bore a gallery and lay eggs. Tiny grubs hatch and bore through the cambium away from the egg gallery. The grubs pupate at the end of the larval tunnel, and new bark beetles emerge from the pupae after a short while (summer) or a long while (winter). These new beetles often bore out through the bark. Trees from which bark beetles have emerged appear to have been blasted with bird shot. Aside from the additional stress bark beetles put on trees as they feed in the cambium, bark beetles often infect trees with fungi, hastening tree decline.

In fall, lady beetles seek a dry, sheltered, overwintering site. In the following spring, they disperse to find plant pests for food and oviposition (egg laying). In North Carolina, overwintering groups of lady beetles are small (rarely up to 300 or 400 individuals). In western states, lady beetles congregate by the millions along mountain ridges. Collectors may scoop up bushels of lady beetles to sell to home gardeners for aphid control. Unfortunately, for the western lady beetles to reach the hibernation site, they have to fly long distances. Consequently, when they leave the overwintering site in spring, they instinctively fly long distances to reach a source of aphids. Although lady beetles are helpful and cute, they are not especially clever. Thus, when lady beetles from California are released into North Carolina, they usually leave the area in search of aphids and other plant pests. The home gardener who has released a quart of lady beetles may never see them again, but will at least have the satisfaction of helping to control aphids in someone else's yard.

INSECTS, MITES, AND OTHER PESTS

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Figure 33. Lady beetles; (a-c) adults, (d and e) larvae, (f) pupa-

Moths and Butterflies (Lepidoptera) Even with their scaly wings and tubelike mouthparts (Figure 34), moths and butterflies are actually harmless to ornamental and turfgrass plants. However, they lay eggs from which hatch tiny caterpillars that chew on the buds, flowers, leaves, stems, and trunks of ornamental plants. As caterpillars grow, they molt several times until in the last stage of larval development, some caterpillars may be 3 or 4 inches long. All moth and butterfly caterpillars eventually pupate; moth caterpillars may spin cocoons or burrow into the soil to do so. Butterfly caterpillars often pupate after spinning a silk strand that holds the pupa to a twig. Several families of moths are important ornamental and turf pests. Only one family of butterflies includes pests of ornamental plants. BRUSHFOOTED BUlTERFLIES (Figure 35). The front legs of these butterflies are shaped like tiny brushes. The front legs are not used for walking. Caterpillars of mourning cloak butterflies are called spiny elm caterpillars because of their outrageous spines and their habit of feeding on elm trees. Willow trees seem to be the spiny elm caterpillar's favorite host in North Carolina. Proper identification of this pest is important because when described over the phone it can easily be confused with the gypsy moth. (Spiny elm caterpillars have pairs of red dots down the back; gypsy moth caterpillars have five pairs of red dots and then six pairs of blue dots down the back.) Caterpillars of the variegated fritillary are called pansyworms because they feed on pansies, violas, and violets. Like all nymphalid caterpillars, pansyworms have conspicuous spines along the body.

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Position of Mouthparts When Feeding

Mouthparts Coiled

Figure 34. Structures of moths and butterflies; (a) scales on wings highly magnified, (b) head of moth showing noninjurious mouthparts.

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Figure 35. Mourning cloak butterfly; (a) adult, (b) caterpillar (spiny elm caterpillar), (c) pupa.

Master Gardener Insect Guide

Figure 36. Fall armyworm, (a) adult moth, (b) eggs, (c) fall armyworm, (d) pupa.

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Figure 37. European corn borer; (a) adult, (b) eggs, (c) larva or borer, (d) pupa.

OWLET MOTHS (Figure 36). Owlet moths include cutworms, climbing cutworms, armyworms, budworms, the cabbage looper, the iris borer, and the corn earworm. These caterpillars are primarily pests of herbaceous bedding plants in vegetable gardens and home grounds. Some of the climbing cutworms feed in the buds of azaleas and rhododendrons in late winter. Most kinds of owlet moth caterpillars pupate in the soil. There may be two to three generations per year. The armyworm, fall armyworm, and several kinds of cutworms feed on lawn grasses. All common lawn grasses may be attacked; if damage occurs during hot, dry periods, the grass may be killed. These insects hide in the soil, in thatch, or at the base of plants during the day and feed at night. Fall armyworms usually attack grasses from early summer to fall. SNOUT MOTHS AND GRASS MOTHS (Figure 37). The caterpillars of snout moths are usually slender and often web foliage together or bore into the stems. This family includes the European corn borer (bores into stems of flowers), sod webworms, and leaf crumplers. Snout moths are named because in some species, the mouthparts of adults form a prominent snout. Snout moth caterpillars often pupate in webbed foliage or inside the stem, and two or three generations occur per year. Several species of sod webworms, the larvae of “lawn moths” (grass moths), attack grass in North Carolina. The adult moths fold their wings closely to their bodies when resting and hide in shrubbery or other sheltered spots during the day. In early evening, they fly over the grass and the females scatter their eggs. The larvae feed at night and retreat into a silken web during the day. The larvae chew off blades of grass in small patches. Sod webworms begin feeding as soon as they hatch and build burrows or tunnels near the surface of the soil to hide in as they grow larger. Sod webworms prefer newly established, wellmanaged lawns and golf greens. Insecticide treatments should be started immediately after damage is noticed. This pest is most troublesome in summer and early fall.

ROYAL MOTHS (Figure 38). Orangestriped oakworms, hickory horned devils, and greenstriped mapleworms are characteristic of royal moth caterpillars. These caterpillars have two or more spines near the head; they look ferocious but are actually harmless. These caterpillars are tree pests; they pupate in the soil. Usually royal moths have only one generation per year.

Figure 38. Greenstriped mapleworm; (a) adult (rosy maple moth), (b) eggs, (c) greenstriped mapleworms, (d) pupa.

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INSECTS, MITES, AND OTHER PESTS

TIGER MOTHS AND WOOLLYBEARS (Figure 39).

Aside from woollybears, the most conspicuous tiger moth is the fall webworm, which has two generations each summer. These caterpillars spin a loose web around the leaves as they feed. The webbing becomes more abundant as the caterpillars grow. By autumn, entire tree tops may be completely webbed over. When ready to pupate, fall webworm caterpillars descend and spin cocoons on or in the litter at the base of the tree.

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TENT CATERPILLARS (Figure 40). Eastern tent caterpillars form conspicuous, dense white “tents” of silk in the crotches of apple, crabapple, wild cherry, and related trees and shrubs in early spring. By late spring, these dark caterpillars spin cocoons on various objects and pupate. Moths soon emerge and lay eggs that will not hatch until the following spring. The forest tent caterpillar is similar to the eastern tent caterpillar in all aspects except that no tent is constructed; these caterpillars merely group together in clusters when resting. HANDMAID MOTHS AND OTHERS (Figure 41).

Caterpillars of handmaid moths have one thing in common: when disturbed, they lift their front and rear, forming a U-shape. Pests in this family include azalea caterpillars, walnut caterpillars, and yellownecked caterpillars. They usually produce one generation per year, and the caterpillars dig into the soil to pupate and overwinter. These caterpillars usually feed in groups and may grow to 2 inches long. It is a memorable sight to see a group of these large caterpillars suddenly assume the U-shaped position all at once when bumped.

Figure 39. Fall webworm; (a) moth, (b) and (c) fall webworms, (d) pupa.

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b Figure 40. Eastern tent caterpillar; (a) adult, (b) egg mass, (c) larva, (d) tent in crotch of small tree.

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Figure 41. Handmaid moths; azalea caterpillar, (a) adult, (b) caterpillar.

Master Gardener Insect Guide

TUSSOCK MOTHS (Figure 42). The most feared

caterpillar in the tussock family is the gypsy moth caterpillar, which defoliates millions of acres of hardwoods in the Northeast each year. This hairy caterpillar is fairly ordinary looking except for one characteristic: It has five pairs of blue bumps and six pairs of red bumps down its back. Gypsy moth caterpillars are the only caterpillars with both blue and red bumps. Fortunately, this pest is not widely established in North Carolina yet, but it is always smart to check out any caterpillars just in case. Gypsy moth caterpillars produce one generation, in spring. The moths fly in June and July and lay eggs that hatch the following spring.

Figure 42. Gypsy moth; (a) moth with egg mass, (b) caterpillar, (c) pupal skins.

BAGWORMS (Figure 43). Tiny bagworm caterpillars hatch in spring and feed and spin a bag of silk covered with bits of plant material. They develop throughout the summer and pupate late in the season. Female bagworms lay their eggs in the bag. These eggs hatch the following year. Heavily infested junipers and arborvitae may be killed by bagworms. SLUG AND STINGING CATERPILLARS (Figure 44). The saddleback and puss caterpillars are among the fascinating members of the family of stinging caterpillars. These caterpillars inflict a painful sting that sometimes requires medical treatment, especially for those who are extremely allergic to the venom. Fortunately, these caterpillars are rarely abundant enough to cause significant defoliation.

Figure 43. Bagworm; (a) male moth, (b) two bagworms on juniper twig.

Figure 44. Stinging caterpillars; (a) and (b) hackberry leaf slug, (c) a slug caterpillar, (d) puss caterpillar, (e) and (f) saddleback caterpillar.’

INSECTS, MITES, AND OTHER PESTS

CARPENTERWORM MOTHS (Figure 45). Carpenterworms develop slowly by boring into the wood of living oaks and other hardwoods. It takes two or three years for carpentenvorms to pupate and for the moths to emerge. Female moths have a 3-inch wingspan; the male's wings are smaller. In North Carolina, infested trees are seldom weakened to the point that they break off in windy weather, but it is possible. CLEARWING MOTHS (Figure 46). Clearwing moths resemble paper wasps in appearance and behavior. Caterpillars of clearwing moths bore into the cambium (dogwood borer and peachtree borer) or wood (rhododendron borer and lilac borer) of trees, shrubs, and other plants. When fully developed, the caterpillars spin a cocoon and pupate inside the host plant, and adult moths emerge to mate and lay eggs. Dogwood borers also infest certain twig galls on oak trees; if galls are abundant on oaks, extraordinarily large populations of moths may develop. For this reason, it is well to protect dogwoods from wounds on the bark as wounds are attractive sites for female dogwood borer moths to lay eggs. OLETHREUTID MOTHS (Figure 47). The Nantucket pine tip moth is the most pestiferous member of the family olethreutidae in North Carolina. This small caterpillar mines in needles and then bores into buds of small pine trees, especially Virginia pines. It produces four or five generations per year. Probably the best way to determine when to spray for Nantucket pine tip moths is to hold some infested tips in a plastic bag in the shade. After the small, silvery moths emerge in the bag, wait 10 days and spray with the appropriate pesticide.

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Figure 45. Carpenterworm; (a) moth, (b) eggs, (c) carpenterworm caterpillar, (d) pupa.

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Figure 47. Nantucket pine tip moth; (a) adult, (b) larva, (c) pupa, (d) damage to small cone (arrow).

Figure 46. Clearwing moth borers; (a) moth, (b) larva, (c) pupa, (d) damage to stem.

Master Gardener Insect Guide

Flies, Midges, and Leafminers (Diptera) Flies lay eggs from which maggots hatch. Certain maggots damage plants in several ways. Some species (such as the holly leafminer) mine in leaves, some species (such as the boxwood leafminer) cause galls, and other species (such as fungus gnats) feed on roots.

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GALL MIDGES (Figure 48). The gall midges are among the most fascinating of flies. Midges are very selective of the plant species on which they lay eggs. The most common gall midge is the boxwood leafminer, which emerges each April, mates, and then lays eggs in the leaves of boxwood (and no other kind of plant). Golden maggots hatch from these eggs inducing a blister gall on the lower surface of the leaf. These maggots pupate the following spring and new adults emerge shortly thereafter. Other gall midges form galls on dogwoods (the dogwood club gall), oaks, maples (maple eyespot), and ashes.

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LEAFMINER FLIES (Figure 49). Leafminer fly maggots infest hollies, delphinium, columbine, and other flowering plants. In general, if a plant is evergreen, its leafmjner has one generation per year. If plants are deciduous or annual, their leafminers have two or more generations per year. The flies lay eggs in host plant leaves, and the maggots develop inside the leaf, forming a tunnel or blotch. The maggots pupate inside or out of the leaf and shortly emerge as new adults. Holly leafminer flies (each species of holly has its own species of leafminer) emerge in midto late spring (an excellent time for pesticide treatment).

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f b

A

Figure 48. Gall midges; (a) and (b) maple eyespot galls, (a) top of red maple leaf showing cream and red galls, (b) back of same leaf showing maggots of maple eyespot gall midges, (c-9 dogwood club galls, (c) dogwood clubgall midge, (d-f) galls on dogwood, (g) midge galls on ash leaves, (h-j) boxwood leafminer, (h) adult, (i) leafminer maggot, (j) gall on boxwood leaf opened to show maggot.

Figure 49 Leafminer flies; (a-d) larkspur leafminer, (a) adult, (6) leafminer maggot, (c) puparium, (d) injury of leafminer in larkspur leaf, (e) injury of leafminer in holly (enlarged).

INSECTS, MITES, AND OTHER PESTS

FUNGUS GNATS (Figure 50). Fungus gnats are tiny mosquitolike flies that lay their eggs on the soil of ornamental plants (primarily greenhouse and house plants), especially if the soil contains peat moss. Tiny, slender maggots hatch from the eggs. Mature fungus-gnat maggots are pure white larvae with shiny black heads. The maggots bore into the roots and sometimes even the stems of plants that have been overwatered or have become infested with a fungal disease. The maggots pupate in the soil and new fungus gnats soon emerge to mate and lay eggs for a new generation.

a

b

C

Ants, Bees, Sawflies, and Gall Wasps (Hymenoptera) Most adult insects in this order have one large pair of fore wings and one smaller pair of hindwings (Figure 5 1). The hindwings have a row of tiny hooks that fasten into a groove of the forewings. The wings of Hymenoptera are usually transparent with visible veins. In many Hymenoptera, the ovipositor (egg placer) is modified into a stinger.

Figure 50. Fungus gnat; (a) adult, (b) larva, (c) pupa.

More people die from insect stings each year than from snakebites. On the other hand, many Hymenoptera are beneficial as parasites of aphids, caterpillars, and many other plant pests. Furthermore, bees are extremely beneficial because they pollinate flowering plants.

ANTS (Figure 52). All ants are social. Ants live in colonies or nests; the workers help to raise the siblings and to maintain the colony. Carpenter ants nest in wood and are a nuisance because they sometimes tunnel into porch railings and other structures. Some ants destroy grass seeds on the soil, preventing effective reseeding. Many ants nest in soil. Soil excavated from their tunnels is dropped outside the nest entrance in a ring-shaped ant hill. In landscapes, the soil thus excavated may be considered unsightly. On golf courses, ant mounds may be large enough to cover nearby grass and high enough to dull the blades of a mower. In addition to creating large, unsightly mounds, the potent sting of fire ants also poses a threat to human and animal health.

Stinger

u/

Figure 51. A member of the Hymenoptera showing the tiny hooks on the hind wing that hook the wings together in flight. The stinger is also visible.

Figure 52. Ants; (a) male, (b) queen after losing her wings, (c) eggs, (d) larva, (e) pupa, (f) worker, (9) fire ant mound.

e

Master Gardener Insect Guide

Figure 53. A wild bee in the genus Andrena.

BEES (Figure 53). Many species of bees are fairly similar in appearance and biology. Sweat bees, honey bees, leafcutter bees, digger bees, and carpenter bees are all in separate families. Sweat bees, colletid bees, and andrenid bees often nest in the soil. The mound of soil around the nest entrance disfigures turf in the same way ant hills do; bee mounds sometimes cover nearby turfgrass. Sweat bees are sometimes a problem when they land on people to lick perspiration. The unwary gardener may receive a modest but noticeable sting whenever a sweat bee is trapped against the skin. SAWFLIES (Figure 54). Among the most primitive of the bees and wasps, sawflies are in a separate suborder. Their common name is derived from their sawlike ovipositor (egg placer), which is used to split open plant tissue and insert eggs. Tiny caterpillars hatch from the eggs and feed and molt several times as they grow. Sawfly caterpillars have more pairs of fleshy abdominal legs than caterpillars of moths and butterflies. The sawfly caterpillars spin a tough, brown cocoon and pupate inside. Adult sawflies may emerge a few weeks later, during the following year, or perhaps even two to three years later. Adult sawflies are somewhat flylike in appearance. Some species (such as the redheaded pine sawfly) produce two or three generations per year, whereas some (such as the Virginia pine sawfly) have only one per year. In every generation, a few individuals may not emerge for an extended period.

Figure 54. Sawflies; (a) dusky birch sawfly caterpillar, (b-e) redhead pine sawfly, (b) adult, (c) eggs in pine needles, (d) caterpillar, (e) cocoon.

GALL WASPS (Figure 55). These small to tiny wasps are all fairly similar in shape and color and have the ability to cause galls on plants. (Gall wasps do not sting people.:) Gall wasps are usually very selective about their host plant species and are even selective as to individuals of a species in a landscape. The galls caused by these uniformly drab wasps are sometimes spectacularly unique; the identity of gall wasps is much more easily determined

a

b

Figure 55. Gall wasps, (a) a typical gall wasp about 1/8 inch long, (b) gall on live oak stem, (c) and (d) Neuroterus galls on oak leaves.

ch

INSECTS, MITES, AND OTHER PESTS

from the gall and the host species than from the wasp itself. Many gall wasps have alternating generations, which not only differ greatly in size and gender, but also form strikingly different galls. Thus the offspring (and their galls) more closely resemble the grandparents (and their galls) than they resemble their parents (and their galls). It is not easy to explain why insect galls become more or less abundant from year to year; even more difficult to explain is how to control a particular gall insect. Advice on gall control may be better left to the county Extension agent.

What Are Mites? Unlike insects, in the adult stage, most mites have four pairs of jointed legs. Gall mites have two pairs of jointed legs in the adult stage (Figure 56). Mites do not have wings in any stage, so they must crawl, be blown, or carried from one plant to infest another. Chiggers and spider mites are the most familiar, but there are thousands of mites. The mouthparts of mites are like slender scissors, which pierce the host tissue for easy access to the juice. In general, mites lay eggs and develop through various immature stages resembling adult mites except in size; most plant-feeding mites are very tiny or microscopic. Four families of mites are important plant pests in North Carolina: spider mites, false spider mites, threadlegged mites, and gall mites. Spider mites are the most common and widespread pests of ornamentals in North Carolina.

d

Other Kinds of Pests MILLIPEDES are slender, somewhat wormlike animals, having two pairs of legs on most body segments (Figure 57). For this reason, millipedes are sometimes called “thousand leggers.” Millipedes lay their eggs in damp places. Very young millipedes have six legs; but as they grow, they gain more pairs of legs with each molt. They usually feed on decaying plant matter but sometimes feed on the roots of ornamental plants to obtain moisture when the weather gets dry.Ordinarily, more complaints about millipedes occur during wet weather when people’s homes may be invaded by tens or hundreds of millipedes. When disturbed, some millipedes curl up and secrete a foulsmelling fluid containing cyanide.

Figure 56. Mites; (a) spider mite, (b) false spider mite with two eggs; (c-d) wild cherry pouch gall mite, (c) adult, (d) galls on wild cherry.

b

a

Figure 57. Millipedes; (a) adult, (b) immature.

Master Gardener Insect Guide

a

Figure 58. (a) pillbug, (b) sowbug.

PILLBUGS and SOWBUGS are similar to millipedes in biology and in the damage they cause to ornamental crops, but they differ in that they have only one pair of legs per body segment, for a total of seven pairs (Figure 58). Pillbugs can roll up into small spheres; sowbugs usually cannot roll up. Pillbugs and sowbugs are crustaceans (akin to crayfish) and typically live in damp areas under stones, boards, and dead leaves. Pillbugs and sowbugs sometimes crawl into the drainage holes of house plant pots. These pests work the potting mix out of these holes as they crawl in and out at night, apparently feeding on decaying organic matter. In dry weather, sowbugs and pillbugs sometimes feed on tender plants or roots to obtain moisture. SLUGS are more closely related to clams and octopi than they are to insects (Figure 59). Slugs rasp away and consume plant tissue at night. As they slide along, slugs leave a silvery slime trail, particularly on dry surfaces. They hide under various objects during the day. It is better to put slug baits under a pot or board than to leave the bait out in full sun. Slugs lay eggs in the soil from which hatch tiny slugs. As slugs grow, they first function as males and then develop into females.

EARTHWORMS are popular with fishermen and gardeners, although on fine turf earthworms may cause problems (Figure 60). They tunnel through the soil, consuming both soil and organic matter. They often deposit their waste products as castings above ground. Earthworm castings are sometimes a nuisance because they dull the blades of lawnmowers. Their tunneling helps aerate the soil, and the castings add organic matter, but earthworms are attractive to moles.

a

b

Figure 60. (a) earthworm, (b) earthworm casting.

Figure 59. Slugs and their damage.

CULTURAL AND BIOLOGICAL CONTROL OF INSECT AND MITE PESTS

Cultural Control Cultural methods of suppressing insect and mite problems in the landscape include choosing plants that are not attractive to pests or choosing plants that are tolerant of insects and diseases. Other ways to eliminate pests are by pruning or raking and then destroying infested plant residues. Irrigation also reduces pest populations. Keeping ornamental plants in good health helps these plants to better withstand and repair the damage caused by an insect or mite pest. There is some evidence that healthy trees and shrubs are less likely to be infested by pests than plants in low vigor. Our ability to use cultural control techniques in turfgrasses is somewhat limited because many of the practices that would reduce insect problems result in less than optimum turf. CHOOSING PLANTS. By choosing plants carefully, gardeners can avoid some of the common pest problems. For example, a person wishing to plant hollies for landscaping could choose Japanese holly instead of convex or Helleri hollies, which are much more susceptible to southern red mites. If boxelder trees are desired, male trees rather than females should be planted to avoid troubles later with boxelder bugs, which feed on the seeds of boxelder trees and frequently enter dwellings to overwinter.

If a particular insect pest is a consistent problem in turf, selecting a different grass species might be effective. For example, if chinch bugs are a problem each year in a Saint Augustinegrass lawn, choosing another warm-season grass species would probably eliminate the problem. A few resistant grass varieties are available; however, most are not resistant to pests that are of significance in North Carolina, or they are not varieties that perform well here.

When mowing, never cut more than one-third of the growth. This reduces the stress on the plant and allows the turfgrass to more easily withstand the impact of insect feeding. In general, thatch removal discourages insect problems. A thick layer of thatch provides excellent protection for chinch bugs and some caterpillars from the environment and various predators. In Saint Augustinegrass, thatch removal alone often prevents chinch bug problems. Thatch can also tie up insecticides chemically so that insect pests may survive in spite of the most thoroughly applied treatment. IRRIGATION. Frequent irrigation of turf is helpful because chinch bugs, spider mites, aphids, and other pests are susceptible to fungal diseases that are promoted by high humidity. Spraying infested plants with a strong stream of water dislodges and kills many spider mites, aphids, and other relatively fragile insects. MAINTENANCE OF HEALTHY PLANTS. Maintaining thick, healthy turf usually eliminates problems with ants, digger wasps, and bees. Other practices include patching tree wounds that drip sap and controlling aphid or scale populations that excrete honeydew and attract ants into the lawn. The first step in maintaining healthy turf is to follow recommended management practices. Healthy grass can tolerate low levels of insects without showing obvious signs of damage. Additionally, insects seem to prefer sparse, unthrifty stands of grass, so healthy stands are less likely to be attacked. However, excessive nitrogen fertilization should be avoided. Nitrogen increases the succulence of the turf and may encourage insect attack. Use slow-release fertilizers instead of water-soluble, inorganic nitrogen fertilizers.

PRUNING, RAKING, AND MOWING. Some pests,

Biological Control

such as the azalea stem borer and the dogwood twig borer, can be controlled by pruning them out of infested trees and shrubs and destroying the twigs. If infested twigs are pruned in late spring or early summer, these plants should bloom without any problem the following spring. However, if infested twigs are pruned out in late summer, a larger portion of the branch must be removed (the larvae bore downward inside the stem), and the plant will not have time to set new flower buds before winter. In fall, the fallen twigs of pecans, oaks, elms, hickories and other shade trees should be raked up to destroy the larvae of twig girdlers. These longhorned beetles overwinter as grubs in fallen twigs, and new beetles emerge during the following fall to lay eggs in and chew off more twigs. Sometimes hickories and pecans can be noticeably stunted by twig girdlers.

NATURAL CONTROL. Insect and mite pest populations are usually distributed in relatively small “clumps.” Thus one or two lawns in a neighborhood may be overrun with millipedes or green June beetle grubs or some other pest, and houses two doors away may have almost none. This distribution is called “local abundance.” Insect pests do not occur everywhere every year because every pest is fed upon by parasitic and predacious insects, mites, and diseases. Thus when pests become numerous, parasites and predators are attracted to them and become numerous enough to eliminate the pest species in that local area. The parasites and predators then disperse to seek out more prey. Life for insect and mite pests is somewhat like a game of musical chairs. Pests occupy a plant, then parasites pounce on the plant and consume all the pests that were not lucky enough to disperse to a new plant.

Master Gardener Insect Guide

Sometimes parasites fail to appear when large numbers of pests invade a landscape, and the clumps of insects or mites cover several acres or even hundreds of acres. This usually happens when a new pest invades a region, although it sometimes happens with pests that are native to that region. In this case, it is sometimes desirable to apply some method of pest management to supplement natural pest control. Insects in turf are often controlled by natural forces in the landscape environment. Sometimes, however, natural control is of limited use from a practical standpoint. The best way to ensure that natural control is working for turfgrass is to avoid the unnecessary use of insecticides. Treat only when aesthetic or economic thresholds are exceeded. Several natural control agents may work in a turf area but may leave undesirable results. For example, moles and skunks can do extensive damage while searching for insects (primarily white grubs) in the soil. Other insects also attack white grubs but do a little less damage. Large solitary wasps, often seen flying just a few inches over the grass during the summer, parasitize white grubs and can decrease their abundance. These wasps dig nests in the soil, leaving holes and small mounds of soil. Although the actual damage is usually minor, many homeowners consider the mounds unsightly. One example is the scoliid wasp seen frequently in late summer. This brown and black wasp has two yellow spots (one on each side of the abdomen) and dark metallic blue wings. It often flies in a figure eight pattern over soil infested with grubs of the green June beetle. Scoliid wasps do not sting people but indicate the presence of a grub infestation. In this case, it may be necessary to reduce the numbers of white grubs by biological or chemical control methods to avoid undesirable side effects of natural control agents.

BIOLOGICAL CONTROL. Biological control is the process of reducing the numbers of a pest by using predators, parasites, or disease organisms that ordinarily occur in nature. The most conspicuously successful examples of biological control in the landscape are the uses of two bacteria for caterpillar control and Japanese beetle grub control. Bacillus thuringiensis is a bacterial disease of caterpillars. The spores of this bacterium have been formulated into pesticides that can be sprayed into the environment with little impact on animal and plant health, killing the caterpillars. Milky spore is a disease of Japanese beetle grubs caused by Bacillus popilliae This disease has been used effectively for years. The causative organism is available under a number of different trade names and can be applied as a powder to any turfgrass currently infested with Japanese beetle grubs. The disease is quite effective and long lasting but generally requires at least one year before it noticeably reduces the grub pop-

ulation. Although this disease will infect several species of grub, it is effective against only the Japanese beetle grub. Other examples of biological pest control on ornamentals and turfgrasses are not as successful as the bacteria cited above. Parasites and predators are available through garden catalogs and gardening magazines. These organisms sound extraordinarily efficient and easy to use. However, there are numerous problems associated with using insects and mites for biological control agents, the main one being that unless the predator or parasite has something to feed on, it will starve or will disperse to find prey. If the home gardener discovers a pest for which there is a predator commercially available, by the time the predator is ordered and released onto the infested plant, an unacceptable amount of damage may have already occurred. If the home gardener orders the predator beforehand, it must be stored until the pest appears. Because of the local abundance of insect populations, it may be weeks, months or years before the pest appears. By that time, the predators are likely to have perished.

Figure 61. Scoliid wasp (a) and its grub (b), a parasite of the green June beetle.

b

Figure 62. Green June beetles (a) fly during the summer. The grubs (b) sometimes crawl on top of the soil on their backs.

CALENDARS OF PEST APPEARANCE

Note: Recommendations for the following calendars vary from the mountains to the coast.

Master Gardener Insect Guide

CALENDARS OF PEST APPEARANCE

Crape Myrtle-Pest Control Calend - _--

Master Gardener Insect Guide

CALENDARS OF PEST APPEARANCE

Master Gardener Insect Guide

INDEX

Adelgids .......................... 11 Ants (Hymenoptera) ........................... ............................ 23 Aphids 12 wooly apple aphid, wooly alder aphid ............................ 12 Armored scales ........... ........... 14 tea scale, camellia le Barklice........................... ............. 8 Bees (Hymenoptera) .............................................................. 23 adrenid bees, carpenter bees, colletid bees, digger bees, honeybees, sweatbees..................................................... . 2 4 Beetles (Coleoptera) ........................... bark beetles .................................................................... 16 chafers ..................................... Asiatic garden beetle, green beetle, June beetle, May bee lady beetle ...................................................................... 16 ladybirds, ladybugs ..................... 16 azalea stem borer, dogwood twig borer

Moths (Lepidoptera) ............................................................ bagworms ............. dogwood borer, lilac borer, peachtree borer, rhododendron borer grass moths leaf crumplers, sod webworms royal moths, orange devils, greenstriped mapleworms ....................... handmaid moths ......... azalea caterpillar, yellow necked caterpillar, walnut caterpillar ...................................................... oethreutid moths .............................. ............................. snout moths, european cornborer .............................. slug and stinging caterpillars hackberry leaf slug, puss c caterpillar ...............................

18

18

19

18

18

Biological Control Bacillus Thurengiensis, Bacillus Popillae ......................

28

Boxelder bugs ...... Cultural control ................. Detecting and monitoring pests ................................................ chinch bugs, sod webworms, armyworms

6

............................................. ner flies .........

22

.......................................... Gall wasps ..................................... neuroterus galls ..............................................................

23

....................................

24

8

..............................

13

.....................................

22

boxwood leafminer, dogwood club gall Millipedes .............................................................................. 25 Mistakes in Diagnosis .................................. 2 lady beetle pupae, seedcorn maggot flies, osmocote pellets, oxalis seeds ............................................. 2 Mites 25 chiggers, gall mites, false spider mites, spider mites, threadlegged mites ................................. 25 Mole crickets (Orthoptera) ...................................................... 7

eastern tent caterpillars ............................................ tiger moths .................................................................... fall webworm, woolybears .............. tussock moths ............................................... gypsy moth .............................................................. Natural Control .................................................................... parasitic wasps, scollid wasp ............ Phylloxera ............................................................................ Pillbugs .............................................................. .......................................... ........................................ Psyllids 11 Sawflies (Hymenoptera).......................

19 19 19 20 20 27 27 11

25 9 27

Virginia pine sawfly ......................... Scentless plant bugs ......... 9 Slugs 26 gray field slug, spotted garden slug .............................. 26 Soft scales ............................................................................ 13 wax scales, cottony maple leaf scales, brown soft 13 scale, cottony camellia scale .......................................... cottony cushion scale ............................................. Spittlebugs............................................................................ Thrips ......................... Whiteflies ............................................................................ greenhouse whiteflies, sweetpotato whiteflies, citrus whiteflies .....................................................

26 10 8 12 12

REFERENCES

AG-136, 1982. Insect and Other Pests of Flowers and Foliage Plants. North Carolina Agricultural Extension Service. 77 pp. (Out of print.) AG-189, 1984. Insect and Other Pests of Shrubs. North Carolina Agricultural Extension Service. 199 pp. AG-268, 1982. Insect and Other Pests Associated with Tur- North Carolina Agricultural Extension Service. 108 PP. AG-348, 1985. Turfgrass Pest Management: A Guide to Major Turfgrass Pests and Turfgrasses North Carolina Agricultural Extension Service. 64 pp. Wescott, C. 1973. The Gardener’s Bug Book Doubleday Co., Inc., Garden City, N.Y. 689 pp.

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Prepared by J m s R. Baker end Ridc L Bran&nburg, Extension Entomology

Published by

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