ABSTRACT
In this paper, we report the sowing date and intensity of chemical control on presence of the cereal leaf beetles (CLB) on spring wheat. The CLB monitoring (Oulema melanopus L. and Oulema gallaeciana Voet.) was conducted in May–June of each year, following the announcement of the IOR-PiB in Poznań (Institute of Plant Protection, National Research Institute), that economic threshold levels in Poland of this pest is observed. For the spring sowing dates between (20 March–20 April) and late autumn sowings (21 November–7 December) larger amounts of CLB adults (1.6–1.1) in comparison to early autumn sowings (25 October–02 November) were noticed (0.4). Following the insecticidal seed treatment with imidacloprid, the occurrence of adults was 0.2–0.7 individual per stem, while the use of fungicidal treatment with triadimenol–imazalil–fuberidazol resulted in average 1.1–2.2 individual per stem. The reduction in the number of larvae per stem was 7–10 fold larger following the foliar application (pirimicarb + dimethoate + cypermethrin) compared to the seed treatment with imidacloprid. The lowest grain yield (3.83 t ha−1) from the spring crop without any insecticide was obtained. Foliar application with blend of pirimicarb + dimethoate + cypermethrin increased the yield crop by 0.41 t ha−1 (10.7%) and additionally by 0.78 t ha−1 (20.4%) to compare to the fungicidal control when imidacloprid was used. Wheat seed treatment with imidacloprid and sowing date in autumn showed to be suitable and economically efficient preventive strategies for controlling the pest population.
Disclosure statement
No potential conflict of interest was reported by the authors.