Disease Gallery

Disease Details

Vein Spot
Gnomonia nerviseda
Vein spot disease can cause defoliation during late summer and fall. Infection and defoliation vary with cultivar; some cultivars have been recorded with a defoliation of over 70%. Vein spot is a common disease of pecan leaves. It does not occur on shoots or nuts. In Oklahoma, this disease is usually not serious
Spores of the fungal pathogen are produced in leaf debris from the previous year’s disease. Infection of the current season foliage usually develops following spring rainfalls. If there is less rainfall in the spring months than normal, infection may occur following rainfall in the summer period. Lesions begin to appear in late May.
Lesions of vein spot disease always occur on vascular associated tissues including leaflet veins, midribs, petiolules, and rachises. The lesions are similar in size to scab lesions, but have a smooth surface and become gray in the center as they age. Vein spot infections (lesions) are very similar to those caused by the scab fungus. Vein spot lesions, however, tend to be linear rather than round and also tend to be restricted to veins.