Farm406

FIGURE 10. Powdery mildew, top, forms a white mat of fungal hyphae on the leaf surface and can be rubbed off. Fungicides and dessicants cannot penetrate this thick layer of fungus. Powdery mildew (Erysiphe pisi, E. trifolii, E. baeumleri, and Leveillula taurica) occurs sporadically in Montana and North Dakota, and generally occurs late enough in the season that it is not economical to control. Many varieties susceptible to powdery mildew grown in Montana can be difficult to grow elsewhere due to higher humidity and rainfall, which promote disease. is can be a dangerous practice in wet years. Early infections with powdery mildew can cause significant yield loss. e pathogen resides on infected trash, leguminous weeds or volunteer plants from previous crops. Infected plants are covered with a white powdery mass of spores that can be rubbed off the leaf (Figure 10). Disease develops at moderate to warm temperatures (70 to 85°F) and is favored by overnight dew, not rain. It can cause the crop to mature unevenly and cause problems with harvest, but desiccants will not be able to penetrate the mat of fungus and are thus not recommended. Fungicides are available for disease management early in disease development. Gray mold (Botrytis) is considered of minor importance on pulse crops in the United States, but can be serious when flower and pod infection occur. e disease is caused by Botrytis cinerea in chickpea and lentil. Symptoms initially start as water-soaked lesions on stems, branches, leaves, flowers, and pods, then progress to grey/brown lesions and are oen covered with a grey fuzz consisting of fungal hyphae and spores. e pathogen aacks all aerial parts of the plant, but prefers blossoms and pods. Photo: Sam Markell 57 farm406

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