Wheat Streak Mosaic VirusWheat Streak Mosaic Virusand the Wheat Curl Mite
Daniel Waldstein
Crop Protection SpecialistCrop Protection Specialist
North Central Research Extension Center
Mi t ND 58701 7662Minot, ND 58701‐7662
WSMV SymptomsWSMV Symptoms
• Yellowing with green lines or splotchesYellowing with green lines or splotches (Nitrogen deficiency should not have green lines)lines)
S ld l• Symptoms most severe on older leaves
• Younger leaves have more of mosaic symptomsy p
D. E. Waldstein, NDSU
D. E. Waldstein, NDSU
D. E. Waldstein, NDSU
Mite‐Virus InteractionMite Virus Interaction
• Virus can be picked up by the mite with 10‐30Virus can be picked up by the mite with 10 30 minutes of feeding
• Virus remains active in the mite for 7‐9 days
• Virus remains in mite from stage to stage but g gis not transferred to the eggs (next generation)g )
Wheat Curl Mite BiologyWheat 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 DynamicsWheat Curl Mite Population Dynamics
• Spread by wind‐‐‐temps. of 65 F and 15+ m.p.h. wind p y p pwill cause widest spread
• Populations explode with temps in the 70’s• Populations explode with temps. in the 70’s
• Life cycle of 7‐10 days with optimum temps.Life cycle of 7 10 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 HostsWheat Curl Mite Hosts
• Best hosts: Wheat (winter, spring, and durum)est osts: eat ( te , sp g, a d du u )
• Good hosts: Proso Millet, Downy chess, Sandbur,Good 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 SurvivalWheat Curl Mite Survival
• Must be in contact with green tissue of suitable ghost to survive
• Survive only 8 hrs. at 75 F without food or water
T d t b i t t d f th l t• Tend to be in protected areas of the plant
• Insecticides/miticides not effective because mites• Insecticides/miticides not effective because mites are in protected areas of plant and extremely fast rate of increase in populations
Virus SusceptibilityVirus Susceptibility
• High: Wheatg
• Moderate: Barnyard grass, stinkgrass, witchgrass, y g g ggreen foxtail
• Slight: Barley, oats, rye, sorghum, foxtail millet, prosomillet, jointed goatgrass, downy brome, Japanese brome cheat grass sandbur crabgrassbrome, cheat grass, sandbur, crabgrass
• Resistant:Most corn hybrids, Canada wildrye, yellowResistant: Most corn hybrids, Canada wildrye, yellow foxtail
WSMVManagement: VolunteersWSMV Management: Volunteers
• Control winter wheat and spring wheatControl winter wheat and spring wheat volunteers and grass weeds with herbicides/tillage (“break the green bridge”)herbicides/tillage ( break the green bridge )
C l l 2 k i l i• Control at least 2 weeks prior to planting
• Mites do not survive on dead tissue
WSMVManagement: Planting DateWSMV 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 orpopulations 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
WSMVManagement: VarietiesWSMV Management: Varieties
• AC Radiant‐ Lethbridge Alberta Canada winterAC Radiant Lethbridge, Alberta Canada winter wheat 2007 release; resistant to mitehttp://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