Extracts of Dalmatian chamomile (Pyrethrum cinerariaefolium Trev) grown in the greenhouse complex of the Institute of Phytopathology were obtained. The resulting extracts were isolated from the dried inflorescences of this plant, by an initial stepwise extraction of lipid fractions with a mixture of dichloroethane / petroleum ether, methanol and a mixture of methanol / petroleum ether, followed by purification on activated carbon. By further separation of the obtained extracts by preparative column chromatography, biologically active fractions with different contents of natural insecticides from the pyrethrin group were isolated. The content of biologically active components in various fractions was determined by the methods of chromatomass-spectrometry. It was found that low-polarity eluents (hexane / chloroform) recover pyrethrin I, cinerin I, and jasmolin I most fully, and the maximum recovery of pyrethrin II and cinerin II is observed when using relatively polar eluents (hexane / acetone). The insecticidal effect of the end products on the great cereal aphid (Sitobion avenae) was studied. It was found that the maximum insecticidal effect (100% mortality of insects) was exhibited by the pyrethrine fraction isolated during extraction with low-polarity eluents (hexane / chloroform). It was found that the pyrethrine fraction isolated during extraction with relatively polar eluents (hexane / acetone) exhibited a moderate insecticidal effect (77–81% of insect mortality). It has been shown that Dalmatian chamomile extracts have a high insecticidal effect against such a pest of cereal crops as the large cereal aphid and can be successfully used as effective, environmentally friendly natural insecticides, including in the form of biologically active additives to commercial insecticidal preparations.
To prevent the resistance of insect pests to insecticides, various methods are used - the rotation of the drugs used, the joint application of drugs from different chemical groups, the use of the fumigation method of biologically active compounds, as well as the inclusion of synergistic substances in insecticidal compositions that enhance the biological activity of the main active substance. The use of synergistic substances can significantly increase the effectiveness of insecticides at a lower consumption rate of the drug. The aim of the work was to develop effective insecticidal pyrotechnic compositions, including environmentally friendly synergistic substances based on sesame oil. As a result, effective insecticidal compositions were developed based on neonicotinoids, pyrethroids, organophosphorus compounds and sesame oil, which provides a significant synergistic effect of active substances on insect pests of agricultural crops - greenhouse whitefly (Trialeurodes vaporariorum). It was shown that during the treatment by spraying, the composition containing 24% of sesame oil, as well as 86% of neonicotinoids, pyrethroids, and organophosphorus compounds had the greatest insecticidal effect (27% death of insects). When carrying out the treatment by fumigation, the compositions containing 23–24% of sesame oil, as well as 87–86% of these insecticides, had the greatest insecticidal effect (more than 90% of insect death). It is shown that the developed compositions can be used both by spraying agricultural plants and by fumigation, by burning a pyrotechnic composition mixed with a composite base. Fumigation has been found to be the most effective method of delivering insecticidal compositions to pests of agricultural plants.
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