Study of phytotoxicity of Lumax herbicide in grain maize crops under conditions of the South of the Far East

Abstract

The phytotoxicity of the herbicide Lumax to the hybrid population of corn P 8521, consisting of three active substances: C-metolachlor, terbutylazine and mesotrion, was studied. The studies were conducted in the Primorsky Territory in 2020 and 2021 on 2 backgrounds: clogged and weed-free which was regularly weeded during the growing seasons. The herbicide was applied before germination, in phases 2-3 and 5-6 of corn leaves at consumption rates of 4 (recommended) and 8 l/ha (twice the recommended). The soil of the experimental plots is meadow-brown podzolized, medium loamy, containing 3.8% humus in the arable horizon, PH 5.0-5.9. The herbicide Lumax, applied in the phase of 5-6 leaves, during the growing season had a phytotoxic effect on plants and corn grain yields. A significant decrease in the grain harvest was noted in 2021 when during the II and III ten-day periods of June and July there were only 35 mm of precipitation, while the norm for this period was 187 mm. When applying Lumax herbicide in the phase of 5-6 leaves, the cob length, the number of grains in it, the weight of the cob and grains from it, as well as the weight of 1000 grains significantly decreased. Corn is more tolerant to Lumax herbicide when used in the 2-3 leaf phase and less tolerant when used in the 5-6 leaf phase.