Abstract

Onion (Allium cepa L.) and garlic (Allium sativum L.) are the most important commercial crops grown all over the world and consumed in various forms. In India, onion and garlic have been under cultivation for the last 5000 years. It is generally used as vegetables, spices or as medicines. India ranks second to China in area and production in both onion and garlic, but ranks 102^nd for onion and 74^th for garlic in terms of productivity. These crops are generally grown throughout the country especially in the states of Maharashtra, Uttar Pradesh, Orissa, Gujarat, Madhya Pradesh, Haryana, Punjab, Rajasthan, Uttaranchal, Jammu and Kashmir, Bihar, Andhra Pradesh and Karnataka. The onion and garlic crop is attacked by many diseases and insect pests at different crop growth stages which causes considerable losses in yield. Apart from reduction in crop yield, the disease and insect pests also poses harmful effects during harvesting, post harvesting, processing and marketing stages, which lower the quality and export potential of the crops that significantly causes the economic loss. The diseases and insect pests alter the cropping pattern and also affect the local and export markets. The consistent use of chemicals to control the plant diseases and insect pests not only poses a serious threat to the environment and mankind but also slowly build up resistance in the pathogens and insect pests.  Most of the new generation pesticides are systemic in their mode of action which may leads to certain level of toxicity in the plant system and thus resulting health hazards. Further, it disturbs the microbial diversity which is an important part of the ecosystem. All these factors have led to new dimension in research for biological control and integrated approach for the management of plant diseases and insect pests. Important diseases and insect pests affecting the onion and garlic crops along with their management are briefly summarized in the present manuscript.

Key   words: Onion (Allium cepa L.), garlic (Allium sativum L.), Trichoderma viride, bulbs.