Non-chemical Control of Potato Early Blight Caused by Alternaria alternata

Document Type : Original Article

Authors

1 Department of Botany, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt

2 Botany Department, Faculty of Science, Cairo University, Giza, Egypt

3 Department of Microbiology, Soil, water and environmental Research Institute, Giza, Egypt

Abstract

Early blight of potato caused by Alternaria alternata (Fries) Keissler is one of the factors that affect
potato production. Using chemical control to reduce disease severity represent another risk for
agriculture. Biological control, using microorganisms, as well as plant extract and compost are safe
measures that give reliable control. Applying either measure of control reduced disease incidence to less
than 2% during two successive seasons. Microbial spray of diseased potato reduced the disease to various
extents. Trichoderma sp. was the most effective among all tested microorganisms, followed by
Penicillium sp. On the other hand, alcoholic extract of three plants was more effective than their water
extract. However, water extract showed highly significant reduction of disease incidence. Polygonum
gave the highest reduction of disease incidence in both cases. Also water extract of compost greatly
suppressed early blight when applied as spray to potato leaves. Duration of extraction may affect the
ability of compost extract to suppress disease. All results were comparable to that of fungicides.

Keywords