Wheat Streak Mosaic Virus Wheat Streak Mosaic Virus and the Wheat Curl Mite Daniel Waldstein Crop Protection Specialist Crop Protection Specialist North Central Research Extension Center Mi t ND 58701 7662 Minot, ND 58701‐7662
WSMV Symptoms WSMV Symptoms • Yellowing Yellowing with green lines or splotches with green lines or splotches (Nitrogen deficiency should not have green lines) • Symptoms most severe on older leaves S ld l • Younger leaves have more of mosaic symptoms y p
D. E. Waldstein, NDSU
D. E. Waldstein, NDSU
D. E. Waldstein, NDSU
Mite‐Virus Mite Virus Interaction Interaction • Virus Virus can be picked up by the mite with 10 can be picked up by the mite with 10‐30 30 minutes of feeding • Virus remains active in the mite for 7‐9 days • Virus remains in mite from stage to stage but g g is not transferred to the eggs (next g generation) )
Wheat Curl Mite Biology Wheat Curl Mite Biology • Carrier (vector) for wheat streak mosaic virus ( ) • Egg, 2 larval stages, and adult • Mite is approximately 1/100 inch long (should be visible with 10x magnification) visible with 10x magnification) • Cigar shaped body with forward directed legs • Can overwinter as adults, larvae, or eggs
Wheat Curl Mite Population Dynamics Wheat Curl Mite Population Dynamics • Spread by wind‐‐‐temps. of 65 F and 15+ m.p.h. wind p y p p will cause widest spread • Populations explode with temps. in the 70’s Populations explode with temps in the 70’s • Life cycle of 7 Life cycle of 7‐10 10 days with optimum temps. days with optimum temps. • Potential for one female to produce 3 million offspring in 60 days • Population growth slows in hot, dry conditions Population growth slows in hot dry conditions
Wheat Curl Mite Hosts Wheat Curl Mite Hosts • Best hosts: Wheat (winter, spring, and durum) est osts: eat ( te , sp g, a d du u ) • Good Good hosts: Proso Millet, Downy chess, Sandbur, hosts: Proso Millet, Downy chess, Sandbur, Smooth Crabgrass • Fair hosts: Corn, Western Wheatgrass, Cheat, Japanese chess • Poor hosts: Barley, Rye, Barnyard grass, Foxtail
Wheat Curl Mite Survival Wheat Curl Mite Survival • Must be in contact with green tissue of suitable g host to survive • Survive only 8 hrs. at 75 F without food or water • Tend to be in protected areas of the plant T dt b i t t d f th l t • Insecticides/miticides Insecticides/miticides not effective because mites not effective because mites are in protected areas of plant and extremely fast rate of increase in populations
Virus Susceptibility Virus Susceptibility • High: Wheat g • Moderate: Barnyard grass, stinkgrass, witchgrass, y g g g green foxtail • Slight: Barley, oats, rye, sorghum, foxtail millet, proso millet, jointed goatgrass, downy brome, Japanese brome cheat grass sandbur crabgrass brome, cheat grass, sandbur, crabgrass • Resistant: Resistant: Most corn hybrids, Canada wildrye, yellow Most corn hybrids, Canada wildrye, yellow foxtail
WSMV Management: Volunteers WSMV Management: Volunteers • Control Control winter wheat and spring wheat winter wheat and spring wheat volunteers and grass weeds with herbicides/tillage (“break herbicides/tillage ( break the green bridge the green bridge”)) • Control at least 2 weeks prior to planting C l l 2 k i l i • Mites do not survive on dead tissue
WSMV Management: Planting Date WSMV Management: Planting Date • Winter Wheat: plant toward end of window; p ; early planting at higher risk with warmer temps. and higher mite activity • Spring Wheat/Durum: plant early before mite populations build up in winter wheat or populations build up in winter wheat or volunteers and moves into spring grain • If mite moves into HRSW at flag leaf or later yield loss is minimal
WSMV Management: Varieties WSMV Management: Varieties • AC AC Radiant Radiant‐ Lethbridge, Alberta Canada winter Lethbridge Alberta Canada winter wheat 2007 release; resistant to mite http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex11601
• Mace‐ USDA ARS and Nebraska Ag. Exp. Station hard red winter wheat 2007 release; resistant to the virus •
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=228024