Agronomic Crop Disease Update

Bob Mulrooney, Extension Plant Pathologist;

It has been a tough year for wheat production. The wet fall delayed planting, then large areas have been inundated with water for long periods of time and there has been grazing by geese. Areas of the state where wheat has survived but under very wet conditions may be at risk from Pythium root rot if wet conditions persist. The other threat, as if there wasn’t enough trouble for wheat, is from the fungal transmitted soilborne viruses, wheat soilborne mosaic virus and wheat spindle streak mosaic virus (WSSMV). Wet soils in the fall following planting can result in severe infections of wheat soilborne mosaic virus that appear as irregular stunted areas in low areas of the field. Mild stunting and yellow green mottling, dashes and streaks on the leaves are diagnostic for WSSMV. There are no controls for either disease for the present crop. Resistant varieties for both diseases are available.

Soybean Cyst Nematode Survey
I am waiting on the results of the last two soil samples before presenting the results of the Delaware Soybean Board sponsored survey for SCN in Delaware. The results so far have confirmed a shift of the race composition in Delaware soybean fields and the nasty nematode has not gone away.