INSECT PESTS OF FORESTRY PLANTS AND THEIR MANAGEMENT.

Indian arid zone covers 31.7 million ha hot desert and 0.78 million ha cold desert, which is about 12 percent of the country’s total geographical area. The mean annual rainfall in the region varies from 100 mm in the north- western sector of Jaisalmer to 550 mm in eastern districts of Rajasthan, Gujarat and Haryana. The rainfall is highly erratic having 65 percent coefficient of variability. The vegetation in the Indian arid zone is very sparse , scanty and thorny. However, the forests and trees like many other plants, suffer from attack by insect pests and diseases which cause a lot of damage, resulting in poor tree growth, poor timber quality, and in some cases, complete destruction and reduction of forest cover in Indian arid zone also. Thus, trees and forests need to be protected from these agents of destruction. With the ever increasing human and livestock population, the amount of forest per capita is declining particularly in the less industrialized or developing areas of the world. It is estimated that the land under forest in developing countries is about 2100 million hectares, or more than half of the forested land on earth. Considerable effort is needed therefore to increase the productivity of the existing forests and to afforest suitable areas. Diseases and insect pests constitute the major biological determinants of forest productivity in the natural forests and particularly in plantations, thus offsetting the effort in increasing wood production to meet the growing needs of an increasing population. The trees selected for seed production can have individual branches covered with sleeves or pollination bags made from woven glass fibre material to exclude the pest species. Insecticides like Endosulphan and Tetrachlorvinphos are effective against bruchids. Some parasites and predators can be successfully used to control the bruchids Parasites attack on egg, larvae and pupal stages. Bruchid eggs, because of their position on the out side of a pod, are easily located by parasitoids. Uscana sumifumipennis has been reported be a group of egg parasitoids associated with bruchids. Bruchids fall to complete their life cycle in presence of mites (Acarina) of the genus Pymotes. They feed on egg, larvae pupae and adults of bruchids. Pymotis boylei is most probably the species which attacks on bruchids