Control of plum fruit moth, Grapholita funebrana Tr., by ISOMATE® – OFM TT dispensers in plum orchards of Bulgaria

Abstract: Plum is a traditional fruit crop in Bulgaria. The plum fruit moth, Grapholita (syn. Cydia) funebrana (Tr.), is an important and the most difficult pest to control in plum orchards. The larvae of summer generation feed on fruits and caused damage from early summer till the harvest time. For a long time, pest management in stone fruit orchards in Bulgaria relied on organophosphate and pyrethroid insecticides. Considering environmental concerns the eco-friendly means of control, alternative to chemical insecticides are urgently needed. The ecological approach imposes a wider application of the methods of pest management that decrease or completely eliminate use of chemicals polluting the environment within the integrated fruit production systems. Mating disruption (MD) is a promising solution for control of different pests, among them plum fruit moth. The possibilities for reducing the number of treatments with chemical insecticides against pests in plum orchards of Bulgaria, by use of synthetic sex pheromones have been studied. The trials were carried out in an isolated 2.5-ha private plum orchard in two consecutive years – 2017 and 2018. Catches of male moths in pheromone traps were completely inhibited in the MD block, whereas they were numerous in the reference, conventionally treated orchard during both years of study. Isomate OFM TT dispensers, installed before the first flight of Grapholita funebrana males, reduced fruit damage significantly. The percentage of fruits containing plum fruit moth larvae was below the Economic Injury Level (EIL). The positive results obtained in this study indicate that mating disruption for control of plum fruit moth may be an effective alternative to conventional (pesticide) treatments. The studies are being continued.