Phytosanitary management in agricultural crops under irrigation

Abstract

The article presents the results of long-term (1988-2020) entomological studies on the study of entomofauna complexes in irrigated agricultural landscapes. It was found that irrigation has a positive effect on the biodiversity increasing of the entomological component of the agroecosystems biotic components. The data of studying of the agricultural landscapes entomocomplexes species composition are presented. So, in the south-east of the European part of Russia (the Lower Volga region), 1432 insects species were recorded in irrigated agrocenoses, and 1582 species were recorded in natural adjacent biotopes (forest belts, forest belts edges, roadsides, etc.). 982 species were recorded in agrocenoses without irrigation. The paper considers the results of studying the species abundance, the regularities of the dynamics of the insects number under the irrigation conditions of the Lower Volga region. The data on the mesophytic microclimatic parameters formation in irrigated agrocenoses are presented. It is shown that the microclimate is one of the main factors determining the increase in biological diversity of entomocomplexes of irrigated agrocenoses. The species diversity and meso- and hygrophilous insects number also increase due to the appearance of additional microstations in irrigated agrocenoses (irrigation canals, storage ponds, spillways, etc.). The formation of polydominant entomological communities under irrigated conditions, which increase the balance of the agroecosystem, including by optimizing its trophic structure, has been established. On irrigated crops, there are more favorable ratios between pests and useful entomofauna, in connection with which the self-regulating ability of entomofauna complexes is enhanced. At the same time, the pesticide load on irrigated agricultural landscapes is reduced by 40-50%.