PHYTOSANITARY MONITORING RESULTS OF HAZELNUT AGROCENOSES IN HUMID SUBTROPICS OF RUSSIA

Hazelnut is a valuable nut–bearing crop, widely grown in warm regions of the world, including the Black Sea coast of Krasnodar Territory. In the humid subtropics of Russia, industrial hazelnut plantations currently occupy 2.1 thousand hectares, about 1.5 hectares of hazelnut plantations are in the private sector. In recent decades, there has been a decrease in crop yields due to the lack of proper agrotechnical care and pest management, which leads to losses from 35 to 85 %. The purpose of these studies is to clarify the species composition of economically significant harmful organisms in hazelnut agrocenoses in the humid subtropics of Russia, as well as to assess their distribution and development degree. Phytosanitary surveys of hazelnut agrocenoses were carried out in industrial plantations of Greater Sochi in the period from 2018 to 2022. The monitoring results have shown that phytosanitary condition of hazelnut plantations manifests a tendency to worsen. During the observation period, an outbreak of gradation of the American white butterfly Hyphantria cunea Drury was observed in the region. Among its forage species, hazelnuts are in the preferred group. In 2018–2019, crown damage (up to 40 %) was noted in some areas of Sochi. In agrocenoses, the following species new for the crop have appeared – the brown marmorated stink bug Halyomorpha halys Stål, the citrus flatid planthopper Metcalfa pruinosa Say, the oak lace bug Corythucha arcuata (Say), powdery mildew Erysiphe corylacearum U. Braun & S. Takam. The most serious pest of hazelnuts at the moment can be considered the brown marmorated stink bug. In the absence of protective measures, crop losses from this pest reach 80 % in some years. In order to obtain stable yields, it is necessary to improve the hazelnut protection system in the region.