Biological and economic efficiency of optimised pest control schemes for mandarin fruit in Abkhazian

Abstract

Abkhazian mandarin crop is infected by over 50 pest species incurring marketable yield losses up to 83 %, which prioritises the development of new crop protection strategies that avoid organophosphorus compound usage leading to pest resistance. The studies were conducted during 2019–2020 in full-grown Citrus unshiu mandarin plantations at the Gulrypsh District of the Republic of Abkhazia adhering to the common protocol. Seven schemes were covered in study for the mandarin crop protection from rust mite Phyllocoptruta oleivora Ashmead and brown marble bug Halyomorpha halys Stål. Two schemes have been selected as optimised: scheme 5 (treatment 1 with Confidor Extra tank mix, 0.05 % WDG (imidacloprid) and 0.15 % Cytovit; treatment 2 with Vertimek tank mix, 0.1 % EC (abamectin, 18 g/L) and 0.15 % Cytovit; treatments 3--4 with Karate Zeon tank mix, 0.05 % OEC (lambda-cyhalothrin, 50 g/L) and 0.15 % Cytovit) and scheme 6 (treatment 1 with Metomax tank mix, 0.15 % SC (methomil 250 g/kg + bifenthrin 25 g/kg) and Vertimek, 0.1 % EC (abamectin, 18 g/L); treatments 2--3 with Karate Zeon, 0.05 % ISS (lambda-cyhalothrin, 50 g/L) and Vertimek, 0.1 % EC (abamectin, 18 g/L); treatment 4 with Karate Zeon, 0.05 % OEC (lambda-cyhalothrin, 50 g/L)). The schemes’ biological efficacy against mandarin pests was 80.0–84.2 and 81.3–87.7 %, providing for an average fruit weight improvement by 89.5 and 94.7 % vs. control, and 22.0 and 25.4 % vs. benchmark, respectively. Yield excess in the schemes was 85.7 and 91.7 % vs. control, and 36.8 and 41.3 % vs. economic cultivation, respectively. Class 1 fruits accounted for 63.3–65.6 % total harvest in schemes 5 and 6, whilst were not obtained in control.