Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Diseases of Vegetable Crops under Protected Cultivation
R.P. Singh, Mamta Mathpal and Supriya Gupta
Department of Plant Pathology, G.B.P.U.A&T., Pantnagar- 263 145 (UK)
India is the second largest producer of fruits and vegetables in the world. Area and
production of vegetables in the world amounts to 7980.7 thousand hectares and 129076.8
thousand tonnes respectively. Out of it India’s contribution in terms of area, production and
productivity is 634.4 thousand hectare, 12433.2 thousand tonnes and 19.6 t/ha respectively. Due
to increasing demand and to maintain year round supply of vegetables, protected cultivation thus
provides a better alternative with huge future prospects.
Polyhouse is a framed structure having 200 micron UV stabilized transparent or translucent
low density poly ethylene or other claddings which create green house effect making microclimate
favourable for plant growth and development. The structure is large enough for person to work
inside, can be made in different shapes and sizes using locally available materials like steel,
alluminium, brick or their combination for its frame. Insect poof net and shading materials are used
to keep insects at bay and to lower temperatures in summer. Though greenhouse technology is
more than 200 years old, but in India, the technology is still in its infancy stage. The area under
green house cultivation is 2000 hactares including 500 ha net house, shed house and 1500 ha
green house, which is mainly in Maharashtra, Uttarakhand, Karnataka, Jammu & Kashmir. There
appears ample scope for increasing area under low cost polyhouse in many folds in peri urban
areas for production of high value vegetables during off season for taking advantage of high price
of available market in nearby cities. Crops like tomato, cucumber , capsicum, etc is being grown
on large scale under polyhouse condition.
Fungal diseases
Fungal diseases constitute one of the biggest group of foliar pathogens causing immense
damage under protected environment. It was found that the incidence and severity of diseases
vary considerably under protected environment when compared to open field. As observed in
tomato, Phytophthora infestans, Pseudocercospora fuligena and Fulvia fulva causing late blight,
black leaf mold and leaf mold respectively were observed to be of higher significance under
polyhouse condition. Further, the notion of early and late blight was found to be obscure under
polyhouse condition. Since it was observed that late blight appears early in the crop season
whereas early blight appears late during crop season. This may be attributed to the fact that
temperature and humidity are nearly balanced inside protected structure, even when outside field
temperature is comparatively low and so on. Alternaria alternata is found to be a major disease
affecting fruits. Capsicum on the other hand is found to be infected primarily by Colletotricum
capsici, Cercospora capsici, Pythium, Fusarium and Phytophthora spp., Stemphylium solani and
Stemphylium lycopersici, Sclerotium rolfsii, Verticillum alboatrum and V. dahlie ,Phytophthora
capsici, Leveillula taurica and Botrytis cineria causing anthracnose, leaf spot, damping off, grey
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