Ascochyta blight is a disease caused by three species of fungi, which are very difficult, if not impossible, to differentiate in the field. Fortunately, diagnosis of a specific pathogen causing ascochyta symptoms is not usually necessary, as control measures are very often the same.
Out scouting? Look for purple-brown lesions on the stem, tendrils and leaves. The lesions will typically form on the lower portion of the plant as a result of higher humidity within the canopy. As the disease pressure increases, lesions will begin to move up the plant, and lower leaves can become entirely blighted.
The presence of disease symptoms, though, does not mean fungicide treatment is warranted. With dry, windy weather, disease movement will slow significantly, and the yield loss may not be severe enough to justify the cost of fungicide application.
In this video, Doug Fehr, technical sales agronomist with DuPont, discusses how to identify ascochyta in field peas, management tactics and tips for fungicide application.
If you cannot view the embedded video, click here.