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Project Leaders:
Gary C. Bergstrom* (Plant Pathology, Ithaca),
Mark E. Sorrells (Plant Breeding, Ithaca), Stewart M. Gray (USDA-ARS,
Plant Pathology, Ithaca)
Cooperators:
Lance Davidson (Graduate Student, Plant Pathology,
Ithaca); Mark Ochs (Consultant-Certified Crop Advisor, Trumansburg);
Bruce Austic and Henry Van Ness (Grain Producer and Land Owner, respectively,
Trumansburg); Janice Degni (CCE Field Crops Specialist, Cortland); Michael
Stanyard (CCE Field Crops Specialist, Newark)
Type of grant: Monitoring, forecasting, and economic thresholds
Project location: Throughout the Northeast
Abstract:
Chemical seed dressings and planting date choice
were assessed in field plots as potential tactics complementary to partially
resistant varieties for the integrated management of Wheat spindle
streak mosaic virus (WSSMV) and Wheat soilborne mosaic virus
(WSBMV) in winter wheat. None of the seed treatment products that provided
protection against WSBMV transmission in controlled environment laboratory
experiments showed a corresponding reduction in natural transmission
and disease development for either WSBMV or WSSMV in our field experiments.
This suggests that seed treatment is not a reliable tactic for disease
control with susceptible wheat cultivars under severe disease pressure.
Seed dressings may still prove useful under less severe disease pressure
and with cereal varieties with partial resistance. A laboratory-based,
soil environment model for WSBMV transmission was a good predictor for
WSBMV disease development, but not for WSSMV disease development in
the field. Relative earliness or lateness of planting is less important
as a control tactic for soilborne viruses than the specific environment
in the weeks following a particular planting date. Improved models based
on the post-planting environment might predict virus-induced losses
of yield potential, and in some cases, growers might avoid purchase
of spring inputs such as pesticides and fertilizer for fields with diminished
yield potential.
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