Biological effectiveness of insecticides in pear psylla control

Abstract

Psylla pyri L. is the pear dominant pest, which damage can reach 7090 %. 57 generations of the insect can develop during one growing season in the south of Russia. Phytophage is difficult to control due to development of insecticide resistance and presence of different growth stages at the same time in summer. Therefore, the research aim was to identify the most effective insecticides with various modes of action that restrain the number and development of pear psylla nymphs. The research tasks were to clarify biological features of pear psylla development and to determine effectiveness of insecticides with various modes of action in controlling P. pyri L. population. Pear psylla development in Prikubansky zone of the Krasnodar region was studied and the results were presented. During the research years, the sum of effective temperatures necessary for: start of egg laying was 40 C (at a threshold of 6 C); beginning of larvae hatching was 121122 C; period from egg to imago 300 C. Pest development monitoring showed that the insect has 6 full generations in the growing season. Field experiments were conducted with Leven pear variety in Prikubansky zone, central gardening subzone of the Krasnodar Territory on the basis of genetic collection of North Caucasian Federal Scientific Center of Horticulture, Viticulture, Winemaking in 20212022 to determine biological effectiveness of insecticides. The results revealed that chemicals based on juvenoids and chitin synthesis inhibitors were not inferior in effectiveness to chemical insecticides. The two-year studies showed that the highest effectiveness after a single application of the chemicals Akarb, WDG (250 g/kg fenoxycarb) and Dimilin, WDG (800 g/kg diflubenzuron) was on the 10th day and amounted to 83.391.7 %, which was higher than the effectiveness of the standard.