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Purpose. To find out the effect of the optimized application of insecticides against pests of sugar beet sprouts on the preservation of the useful entomofauna and reduction of the number of beetroot weevil.Methods. Field, accounting, statistical, analytical.Results. The results of using various insecticides on sugar beet crops and their effect on the useful entomofauna and reduction of the number of beetroot weevil have been analysed. It was found that application of insecticides of various origins at different doses for the protection of sugar beet sprouts from pests in the period from 1981 to 1985 per 100,000 hectares at an average number of treatments of 2.6 totaled 260,000 hectares. In that period, 1,404,000 liters (1404 tons) of insecticides were spent at the average application rate of 5.4 L/ha. Since 1986, when systemic pesticides introduced, the total area of spraying crops with pesticide solutions significantly decreased and in 2001, it was 10,000 hectares with an insecticide expenditure rate of only 1 ton per 10,000 hectares. The population of beetroot weevil for the period of 1985–2015 decreased 1.72 fold in root storage places and 3 fold in sugar beet sowings. At the same time, the number of useful entomofauna representatives, in particular, of Carabidae family, while absent until 1990, increased significantly and in the period from 1991 to 2015 numbered 2.1–3.8 per 1 m2. In addition, such useful insects as malachiid beetle, sulphide fly, goldeneye and Caenocrepis bothynoderis Grom. feed on the various stages of the beetroot weevil development. Bacterial diseases, namely foulbrood and others also regulate beetroot weevil population. Accordingly, entomophages inhibit the massive reproduction of the phytophags and maintain their population density at a certain level. The localization of pesticides on the seed material is an advanced way of the pest control for all crops. This method of control fully meets the requirements to formulations in regard to plant protection from pests and the environment protection from chemical contamination. |
