Effect of insecticidal treatments on the effectiveness of protection of pea crops from bruchus (bruchus pisorum L.)

Abstract

The article analyzes the effectiveness of protective measures of peas from pea beetles. Field experiments were conducted in 2010-2015 in LLC "Commodity economy" Engels district of Saratov region. It is established that the extended period of hatching of larvae and their short-term open stay on pea plants leads to low efficiency of processing at the larval stage and gives reason to consider as an option the use of insecticides against imago. The biological effectiveness of insecticides approved for use on peas was evaluated. The effectiveness of different terms and multiplicity of insecticidal treatments was studied. 5 insecticides from different chemical groups were used in the experiment: actara – neonicotinoid (250 g/kg thiamethoxam); synthetic pyrethroids Karate Zeon – (50 g/l lambda-cyhalotrin) and Fastak (100 g/l alpha-cypermethrin); combined drugs Borey – (150 g/l Imidacloprid+ 50 g/l lambda-cyhalotrin) and Eforia (141 g/l thiamethoxam+ 106 g/l lambda-Cyhalothrin). In the studies conducted to identify the optimal timing of insecticidal treatments, the highest biological effect was obtained on the variant with two treatments: the 1st treatment at the beginning of hatching of larvae + the 2nd treatment at the beginning of mass hatching of larvae. Comparing the percentage of damage to pea beans at different terms and multiplicity of treatments, as well as taking into account the yield obtained - the most optimal period of chemical treatments from bruchus-the beginning of hatching of larvae (10% of empty ovipositors). With a single treatment at the beginning of hatching larvae achieved the highest economic efficiency. Insecticidal treatments in this period, the highest yield of peas was obtained on the variant with the use of a two-component drug Borey-2.45 t / ha. On this variant, on average, for six years, the largest increase in yield to the control was obtained - 0.41 t / ha or 20%. The use of all studied insecticides is economically justified, but the highest indicators of net income and profitability were obtained when using the two-component drug Borey-the level of profitability of 86 %.