Ajanta Birah

Insect Pests of Cotton

Cotton, the king of natural fibres since antiquities, has been entwined in human civilization. It is the most popularly used fibre for clothing and for a host of other purposes since ancient era in India. Cotton is a commercial crop that has deep significance in the economy of the farmers, textile industry and the country where it is grown. Indian farmers cultivate cotton fibre from all the four Gossypium sp. Cotton crop is prone to damage by a number of pests. There are over 166 insects recorded as pests on cotton crop. They are categorized as sucking insects, fruiting body feeders and foliar and stem feeders A spectrum of these insects in different phenological stages and geographical areas denote their adaptability to the habitat of such agroclimatic conditions. In India, cotton crop is damaged right from seedling stage by a number of pests, such as grasshoppers, thrips, aphids and jassids. Sap-sucking pests debilitate the early growth of the crop. Towards the bud-break stage of the cotton crop, the fruiting body (buds, flowers, bolls) feeders such as bollworms appear in the crop. Spiny bollworms, Spotted bollworms, American bollworms and Pink bollworms are the prominent amongst them. The incidence of Spodoptera is observed to occur in large numbers on fruiting parts during certain seasons.

Plant Disease Management: Prospects of Pesticides of Plant Origin

The indiscriminate use of chemical fungicides led to pesticide residues in food products, risk of development of new pathotypes and pollution of soil and water ecosystem. This resulted in several ill effects on human beings, flora and fauna. To overcome the ill effects of chemical pesticides, attention had been paid to explore into products of higher plants for developing novel biopesticides in plant disease management. Our ancestors had been using these botanicals for the management of plant diseases, before the era of conventional fungicides. But the popularity of pesticides of plant origin has again been increasing due to its potential fungicidal action against several plant pathogens without any deleterious effect to the crop plants as well as environment. Several plants have been identified for antimicrobial properties which can suppress the growth and multiplication of plant pathogens, reduction in storage decay and spoilage of food products. The potential plant origin pesticides, viz. neem (Azadirachta indica), garlic bulb (Allium sativum), eucalyptus (Eucalyptus globulus), turmeric (Curcuma longa), tobacco (Nicotiana tabacum), ginger (Zingiber officinale), etc., have been successfully used for the management of several plant diseases. Moreover, seed treatment + foliar spray of freshly prepared garlic bulb extract has resulted into the reduction of Alternaria blight (35.6 %), white rust (50.4 %), powdery mildew (67.7 %) and Sclerotinia rot (80.3 %) in mustard with 27.3 % increase in yield over untreated control. These pesticides can suitably fit in any integrated pest management framework as well as in organic farming system which is a necessity in the current situation. Keeping in view the ever-increasing demand for safe food, pesticides of plant origin have a pivotal role to play in the management of plant diseases in comparison to the conventional chemical pesticides. These pesticides are not only useful to the developing countries due to their easy availability, being relatively cheap, easy sustenance in any crop protection programme and having direct relevance to the developed countries for healthy and quality produce of foodstuffs.