Effectiveness of insecticides against pests of white cabbage grown using seedling technology

Abstract

Among the two methods of growing white cabbage, the seedling technology is more widely used in North-Western Russia. Watering seedlings in cassettes with a systemic formulation of neonicotinoid insecticide Actara, WDG (250 g/kg thiamethoxam) prior to planting has been developed to protect white cabbage from early spring pests: flea beetles of the genus of Phyllotreta and the cabbage root fly. This approach is widely used by commercial growers and its efficacy requires monitoring under current conditions because of a possibility of resistance development. Testing Actara, WDG in 2019 and 2021 at the experimental field of All-Russian Institute of Plant Protection didn’t show any significant decrease of biological effectiveness of seedling treatment. Testing biological effectiveness of systemic insecticides belonging to the chemical class of carbamates Lannate, WSP (250 g/kg metomil) and the new class isoxazolines isocycloseram was carried out in parallel. Biological effectiveness of the latter insecticide was higher compared to Actara against the flea beetles and the cabbage root fly during a 21-day period. In addition, plant infestation with diamondback moth decreased. Efficacy indices of Lannate were significantly lower. Isocycloseram shows a good potential for inclusion into the Index of Registered Formulations of the Russian Federation to protect cabbage against a complex of insect pests. Having an additional active ingredient available to farmers will be begenicial for developing rotation schemes to combat pest resistance.