Early Blight and Septoria Leaf Spot of Tomato

Early Blight and Septoria Leaf Spot of Tomato Sources of Pathogen Seed and transplants. Spores dispersed by wind or water. Crop debris. Potential ...
Author: Jordan Crawford
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Early Blight and Septoria Leaf Spot of Tomato

Sources of Pathogen Seed and transplants. Spores dispersed by wind or water. Crop debris.

Potential Impact Loss of leaves. Sunscald of exposed fruit. Fruit lesions due to EB. Poor fruit quality (lower sugar content). Plants produce less. Severity increases over years.

Septoria Leaf Spot

Management Purchase seed from reliable supplier. Hot water treat seed right before planting. Rotate land. At least 3 yrs, Select EB resistant varieties when suitable. Early maturing varieties have more EB. Indeterminant varieties have less EB. Mulch to interfere with spore dispersal. Hairy vetch might induce resistance. Rows parallel to prevailing wind.

Management Wide row and plant spacing. Separate plantings. Stake or trellise; disinfect first if used. Optimum growing conditions. Drip irrigate or overhead when leaf wetness period minimally extended. Work when foliage is dry.

Management Control weeds and volunteer tomato plants. Rescue treatments – start very early. Use disease forecasting system. Copper fungicides, Sonata biofungicide, PlantShield (not labeled for this use) Incorporate crop residue promptly after harvest.

Early Blight Resistant Varieties Mountain series from NC: Mountain Pride, Supreme, Gold, Fresh and Belle.

Late maturing and fruit small. Cornell Program. First variety expected available in 2007. More suitable for northeast.

New Tomato Selection from Cornell Defoliation due to late blight (US-7) in 1999 Standard Susceptible Variety

Selection with Resistance to early blight and late blight

Treatments - Tomato Early Blight (Abby Seaman, 2001 and 2002) Plantshield (Trichoderma harzianum) drench + foliar applications Mycostop (Streptomyces griseoviridis) - drench Trilogy (neem oil) - foliar Serenade (Bacillus subtilis) - 4 and 8 lb/A foliar Oxidate (hydrogen dioxide) - foliar Drench after transplanting (1 or 9 days after). 3 Foliar sprays at 2-week interval.

Treatments - Tomato Early Blight Treatment

% Diseased Foliage 9/26/01

Plantshield drench

5.6 a

Plantshield foliar

20.0 b

Plantshield drench + foliar

10.0 ab

Trilogy untreated

8.1 a 21.3 b

Treatments - Tomato Early Blight Treatment

% Diseased Foliage 10/3/02

Plantshield drench Plantshield foliar Plantshield drench + foliar Mycostop drench Trilogy Serenade 8 lb/A Oxidate untreated

6.25 bc 8.25 ab 4.50 c 7.25 bc 8.75 ab 7.00 bc 7.00 bc 11.25 a

Organic Tomato Production Fertility Low N - vetch cover crop High N - vetch + peanut meal (50 lb/A N)

Control of Foliar Diseases Compost tea Sonata (2 qt/A)(AgraQuest biofungicide) Compost tea + Sonata Compost tea + rescue fungicides

Organic Tomato Production 6/1

Flail chopped vetch.

6/11 Transplanted. 6/23 Peanut meal applied.

6/10/04

6/17/04

7/9/04

7/28/04

Tomato Foliar Diseases Powdery mildew Septoria leaf spot Bacterial speck Compost tea. Fungicides for organic production.

Foliar Disease Treatments Compost tea applied undiluted with fish hydrolysate (1 oz/15 gal) and nuFilm P (6 oz/A) on 8, 16, 23, and 29 Jul; 4, 11, 17, and 25 Aug; and 1 and 8 Sep.

Sonata (2 qt/A)(AgraQuest biofungicide) applied 11, 17, and 25 Aug; and 1, 8, and 17 Sep.

Rescue fungicides JMS Stylet oil (5 qt/100 gal) applied on 25 Aug and 1 Sep for powdery mildew. copper fungicide Champion (4 lb/A) applied on 3, 12 and 17 Sep for all 3 diseases.

Organic Control Tomato Diseases Treatment

Powdery Mildew Severity 9/1 9/24

Low Nitrogen Nontreated Compost tea (10X; 7/30 - 9/24) High Nitrogen Nontreated Compost tea (10X) Sonata (6X) Tea (10X) + Sonata (6X) Tea + Rescue fungicides (5X)

11 3

53 35

11 10 9 8 9

43 46 62 40 40

Organic Control Tomato Diseases Treatment

Bacterial Speck Incidence (%) 9/24 10/1

Low Nitrogen Nontreated Compost tea (10X; 7/30 - 9/24) High Nitrogen Nontreated Compost tea (10X) Sonata (6X) Tea (10X) + Sonata (6X) Tea + Rescue fungicides (5X)

28 36

44 46

18 36 32 38 38

44 42 44 55 48

Organic Control Tomato Diseases Treatment

Septoria Leaf Spot Incidence 9/24 10/1

Low Nitrogen Nontreated Compost tea (10X; 7/30 - 9/24) High Nitrogen Nontreated Compost tea (10X) Sonata (6X) Tea (10X) + Sonata (6X) Tea + Rescue fungicides (5X)

30 35

41 51

28 56 36 45 39

34 52 48 48 41

Organic Control Tomato Diseases Treatment

Defoliation (%) 9/24 10/1

Low Nitrogen Nontreated Compost tea (10X; 7/30 - 9/24) High Nitrogen Nontreated Compost tea (10X) Sonata (6X) Tea (10X) + Sonata (6X) Tea + Rescue fungicides (5X)

11 3

53 35

11 10 9 8 9

43 46 62 40 40

Why Was Compost Tea Ineffective? Treatment not started early enough? Need to treat seed or seedlings? Effective organisms not present? Change recipe? Change brewing conditions? Applied at wrong time? Evening better than morning?

Nontreated, High N

9/23/04

Compost tea + Rescue fungicides, High N

9/23/04

Compost Tea Recipes 2003 2004 4 lb 4 lb 12 oz 7 oz

4 lb 4 lb 12 oz 4 oz

Ingredient Grape pumice compost Leaf-based compost Vermicompost (manure-based compost) Kelp (Fertrell Liquid Kelp) Fish hydrolysate (Organic Gem Liquid Fish or Neptune’s Harvest Benefits of Fish)

7 oz 16 oz Humic acid (Fertrell Bio-Hume) 60 gal water Brewed 24 hr in Sotillo Brewer

Compost Tea Expenses, 2004 $6.72 8 lb Vermicompost $1.89 16 oz Humic acid (Fertrell Bio-Hume) $1.31 12 oz Kelp (Fertrell Liquid Kelp) $0.52 4 oz Fish hydrolysate (Neptune) $10.35 60 gal $19.16 110 gal/A $1.92 Fish hydrolysate (2 oz/15 gal) $1.64 nuFilm P spreader (6 oz/A) $22.72 per acre cost undiluted

Treatment Costs ($/A) $22.72 Compost tea (undiluted) $26.50 Serenade (4 lb/A) $6.50 Champion (2 lb/A)

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