Cool Weather Viruses In The Mid-Atlantic

May 06, 2014

Symptoms of some viruses, such as Wheat Spindle Streak Mosaic (WSSMV) and Wheat Soil Borne Mosaic (SBWMV) can be more pronounced when temperatures remain cool/moderate as plants enter Feekes 8-9. These viruses can and do impact Mid-Atlantic wheat, yet often they go unnoticed. Why is this? Often as temperatures increase past 64 F the newly developed tissues lack symptoms and therefore these viruses can go undetected in fields. Another reason that these viruses can be overlooked is that symptoms may resemble fertility issues.

Both of these viruses are soilborne and can exist in the soil for many years. Both also are transmitted by a protozoan that does well in wet environments. Therefore, symptoms of these diseases often follow wetter areas of the field. WSSMV derives its name from the thin lesions that form on leaves, which thicken at the center and resemble a spindle. In cool weather you may see these streaks turn brown/black, and some red/brown streaking may occur on the leaves and leaf tips. SBWMV infected plants are often stunted and foliage develops a green / yellow mosaic. Both can be found in the same field at the same time. Confirmation can only be done by using special tests. To have samples tested for virus, send a sample to your diagnostic clinic.

In terms of management of these two viruses, resistance is your best bet, although getting a hold of resistance ratings for specific viruses can be difficult. Crop rotation is not going to provide much of a benefit in fields with a history of these viruses. There is no chemical control.

Source : udel.edu

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