Research Report: Looking for Old and New Foes to Prevent BYDV Transmission on Wheat

By Raul Villanueva and Carl Bradley

Objectives:

1. Monitor abundance of aphid species and viruses in the fall 2016 and spring 2017 in research plots of Princeton
2. Survey for presence of new invasive Sipha maydis in several regions of Western KY, and collect samples for virus detection
3. Evaluate insecticide treatments for aphid management and BYDV’s percentages in treatments

The abundance of aphids were low in western Kentucky in spite of the warm weather conditions of the winter season. However, there were two fields—one in each Todd and Christian counties—where aphid populations were extremely high. In these two fields there might be an apparent failure on the efficacy of a pyrethroid (a possible case of resistance
or an inadequate use of the insecticide).

All 2016 fall wheat foliage samples from eight counties were negative for viruses. However, in the spring of 2017, seven out of 11 samples from 10 counties resulted positive for BYDV.
Insecticide treated vs. untreated seeds were compared, but the small numbers of aphids in the experimental plot did not provide a conclusive evidence for its use. Similarly, the use of a spray program for aphid control was inconclusive for the same reason.