Tajikistan is an agrarian-industrial republic; the territory of agricultural fields is about 901.1 thousand ha, including about 399 thousand ha used for main culture - cotton. The irrigated fields are used intensively; two harvests of crops and vegetables per year, 5-8 harvests of lucerne is a common practice; also the sub-covering and combined cultures. In Tajikistan, development of agriculture and, first of all, cotton-growing, is closely connected with use of pesticides for combating agricultural pests, plant diseases and weeds. Agro-climatic conditions of the republic are favorable for quick reproduction and development of many agricultural pests. Besides, the high level of various plant diseases is registered. Agricultural crops are affected by weeds, especially in irrigated zones, where large number of seeds are coming in with irrigation water. It was determined, that potential losses of harvest by low efficiency of protective maesures are near 30 percent.