Harmfulness of the black plum sawfly (Hoplocampa minuta Christ.) in different types of plantings of plum agroecocenoses in the Right-bank part of the Western Forest-Steppe of Ukraine

Abstract

Goal. To study the degree of damage to the plum ovary by the black plum sawfly in different types of plantings of the plum agroecosystem. Methods. The research was conducted during 2016–2018 in the conditions of the Right-bank region of the Western Forest-Steppe of Ukraine using field and statistical methods. Field studies were carried out in different types of plum plantations, created on clonal BVA-1 and Evryka 99 and seed rootstocks, on which Oda (early), Stenlei, and Bogatyrska (late) varieties were grafted. To establish the beginning and monitor the seasonal dynamics of the flight of the plum sawfly in the «white bud» phenophase, white traps were placed on the trees, on which entomological glue was applied (as it dried and became contaminated, it was renewed). Statistical processing of research results was carried out using the Agrostat computer program package. Results. In the Right-bank region of the Western Forest-Steppe of Ukraine, in 2016–2018, the distribution of the phytophagous Hoplocampa minuta in different types of orchards of the plum agroecosystem was comprehensively studied. The evaluation criteria were the population density of the species and the degree of damage to the plum ovary. The influence of weather predictors in dynamics, varietal characteristics, types of rootstocks, and their combined effect on the onset of flying out, spread and stages of development of the black plum sawfly in different types of plantations was studied. Conclusions. In the Right-bank part of the Western Forest-Steppe, the beginning of the flying out of the black plum sawfly took place in the II decade (from April 11 to 16). In 2016, 13–34% of ovaries were damaged by phytophage, in 2017–2018 — 0.7–5.9%, i.e. 1.9–5.8 times less. Of the investigated rootstocks, the phytophagous H. minuta damaged the plum ovary on the seed rootstock to the maximum extent, among the varieties Stenlei was the most attractive — 1.5–34.7% of the wormed ovary was noted. According to the results of multivariate variance analysis, in 2017–2018, the degree of plum ovary damage by sawfly was 31% determined by weather predictors that contributed to the development and spread of imago, 24% depended on the variety, 14% on the type of rootstock, and 19% on the interaction of the variety and the type of rootstock.