Effectiveness of the application of insecticide preparations against the fall webworm (Hyphantria cunea Drury, 1773)
Abstract
Yu.O. Kolomiiets, S.V. Stankevych*, H.O. Balan, H.O. Kosylovych and Yu.S. Holiachuk
The effectiveness of chemical and biological preparations in destroying caterpillars of different ages of the fall webworm in the Kharkiv region has been analyzed and studied. The most effective chemical and biological preparations for the destruction of fall webworm caterpillars on ash-leaved maple in forest belts have been determined. Experiments were carried out using the following chemical and biological preparations on ash-leaved maple: Nurel D, 55% emulsion concentrate (standard), Koragen, 20% suspension concentrate, Actofit, 0.2% emulsion concentrate, Lepidocide, water-soluble, titer 1.5 × 109 spores/ml, Bitoxibacillin-BTU, preparative tetro mixture, titer 100 × 109 spores/ml. The preparations were selected according to their purpose and effect on lepidopteran pests and with different active substances. In 2019, it was found that the most effective preparation for destroying caterpillars of younger (L1-L3), middle (L2-L5) and older (L6-L7) ages of first generation of the fall webworm is the preparation Koragen 20% suspension concentrate preparation, which provided mortality in the range of 92.9% to 93.9% on the 14th day of use. The use of the Nurel D insecticide, a 55% emulsion concentrate, contributed to the destruction of caterpillars on day 14 after spraying in the range of 85.6% to 91.7%. Against caterpillars of younger ages (L1-L3), middle ages (L2-L5), and older ages (L6-L7) of the second generation in 2019, the most effective preparation was Koragen 20% suspension concentrate, which provided mortality in the range of 84.5%-92.6% on the 14th day of use. The use of insecticide Nurel D, 55% emulsion concentrate, contributed to the destruction of caterpillars on the 14th day after spraying in the range of 80.3-87.2%. The most effective preparation in destroying caterpillars of the younger (L1-L3), middle (L2-L5), and older (L6-L7) ages of the first generation in 2020 was the preparation of Koragen 20% suspension concentrate, which ensured caterpillar mortality on day 14 after use in the range of 81.5%-93.8%. Insecticide Nurel D, 55% emulsion concentrate, compared to the previous preparation, was less effective and ensured 79.7%-83.7% mortality. In 2020, the use of Koragen 20% suspension concentrate preparation against caterpillars of different ages of the second generation contributed to the destruction of 80.7%-91.7%, and slightly less effectiveness was observed with the use of Nurel D insecticide, a 55% emulsion concentrate, that is, in the range of 73.6%-80.0%. The biological preparations studied Actofit, 0.2% emulsion concentrate, Lepidocide, water-soluble, 1.5 × 109 spores/ml and Bitoxibacillin-BTU tetro preparative mixture, 100 × 109 spores/ml, also contributed to the destruction of caterpillars of the fall webworm of younger, middle and older ages at a reasonably high level. However, their action was somewhat slowed down over time. So on day 14, after nests with caterpillars were sprayed with the biological preparation Bitoxibacillin-BTU tetro preparative mixture, titer 100 × 109 spores/ml in 2019, 76.1% of them were destroyed. In 2020-73.3%, Actofit, 0.2% emulsion concentrate, on the 14th day of research in 2019, 85.3% of younger caterpillars died and in 2020-82.7%. In caterpillar control variant, the death of caterpillars was observed in 2020, starting on the 3rd day, but in 2019, on the 7th and 14th day of the first and second generation in the range of 0.3%-2.8%, respectively, which can be caused by different negative factors and natural enemies of the fall webworm.