Winter barley: species composition of phytophags, their harmfulness and assessment of chemical measures effectiveness

It has been determined that in the conditions of Belarus, the formed complex of phytophags in winter barley crops includes 49 species belonging to 28 genera, 19 families, and 7 orders. The most harmful objects during the years of research (2023–2024) were multivorous pests – click beetles (Athoinae and Elaterinae), of intra-stem pests – Oscinella pusilla Mg., leaf-eaters – Oulema melanopus L. and Dolerus niger L., sucking pests – Aelia acuminata L. The conjugation of development of dominant phytophagous species with phenology of winter barley has been specified: during germination – sprouting, the damage is caused by click beetles; leaf development – Swedish flies, cicadas; flag leaf – earing – barley leaf beetle and leaf sawflies; flowering – beginning of grain formation – Swedish flies of summer generation, species of bugs and aphids. New species of pests in agrocenoses were revealed: Trachelus troglodyta Fabr., Cephus pygmaeus L. and Delia coarctata Fall. It has been proved that in agrocenoses of the crop the damage caused by click beetles is significant, with the reduction of their harmfulness, 2.7 % of grain yield was saved. During the vegetation period, reduction of damage to plants by Swedish flies in special experiments allowed to save 2.9 % of winter barley grain, the amount of barley leaf beetle – 3.3 %. For the first time, a high harmfulness rate of bugs was noted – 20.5 % of grain was saved. Relative pest harmfulness coefficients were specified and harmfulness coefficients for adult bed bugs were calculated for the first time, which made it possible to establish EFV of dominant species of phytophags. It was revealed that the winter barley varieties under study were infested and damaged by pests, but the intensity of damage and their density in the crop of each variety differed. High efficiency of insecticides was noted used both by pre-sowing seed treatment (85.3–87.5 %) and by spraying the crops during the vegetation period (87.1–100.0 %) with 1.6–4.5 % of grain saved. At application of insecticide, the number of bugs decreased by 89.3–99.4 %, up to 34.3 % of grain was saved.