Epidemiology of Powdery Mildew, Downy Mildew and Anthracnose Diseases of Grapevine

Abstract

Grape cultivation throughout the world is affected by various disease problems among which three fungal diseases viz. powdery mildew, downy mildew and anthracnose pose serious constraints in getting desired yields of good quality. Study of disease epidemiology plays an important role in working out strategies for effective and timely management of these diseases and in reducing the number of unwanted fungicide applications. A lot of work has been done on these three diseases in different countries to study host-pathogen-environment interactions and suitable correlations have been drawn. Weather parameters play an important role in initiation and development of these diseases. Both downy mildew and anthracnose appear to be largely affected by humid conditions and free moisture in the form of dew or rain are necessary for infection and rainy conditions lead to their epidemic build up. On the contrary, powdery mildew requires relatively dry conditions and moderate temperature. Effects of different climatic factors on the pathogen and disease development and secondary spread as reported for these diseases by various workers has been analysed in this review. Apart from this, some weather based epidemiological models proposed by different workers for these diseases have also been discussed their role in timing first and subsequent fungicide applications highlighted.