Resistance of different blueberry varieties to flower thrips in the conditions of Polissia, Ukraine

Abstract

Blueberries are unconventional berry crop rich in vitamins E, B vitamins, antioxidants, minerals. Their consumption strengthens immunity, memory, vision, and has an anti-inflammatory and rejuvenating effect. Blueberries also enhance cardiovascular function, normalizes blood circulation, and have beneficial effect for the nervous system and gastrointestinal tract. Currently, the most harmful pest in blueberry agrocenoses is the flower thrips, which damages plants during the period of mass flowering. Studying the resistance of blueberry varieties of different maturity to flower thrips makes it possible to reduce the population of plantations with this sucking phytophagous insect. The blueberry varietal collection in the studies consisted of three main groups of different maturity, namely: early-, mid-early- and late- ripening varieties. Although no fully resistant varieties were found in the studies, but the population size was different. The study examined the metamorphosis of the different-aged larvae of the flower thrips, which massively begins its biological development in the VII - phenophase (flowering) of blueberry plant development. Age range monograms were constructed based on the age development of the larva, and the number of phytophagous insects clearly depicted the parameters of the degree of settlement according to the European nine-point scale. The blueberry varieties were divided into three groups according to experimental resistance levels, where early-ripening varieties have a high level of infestation by flower thrips, which massively populates the flower bed during the blueberry flowering phenophase. Phytosanitary monitoring of blueberry agrocenosis allowed us to develop a mathematical model for phenological prediction of the larval period of flower thrips. During May, blueberry thrips are massively colonized by the phytophagous pest, as late blueberry varieties have an extended period in the "flowering" phenophase, so the Elliot and Chandler varieties were less colonized by flower thrips compared to the early blueberry varieties Reka and Duke. Based on the study results, the late-ripening blueberry varieties Elliot and Chandler were identified as the most resistant and can be recommended for commercial cultivation.