Mating disruption for the control of leafrollers on apricots

Abstract

Otago apricots (Prunus armeniaca L.) are damaged by the endemic leafroliers, Planotortrix octo Dugdale and Ctenopseustis obliquana (Walker), and an Australian species, Epiphyas postvittana (Walker), all of which are quarantine pests on export fruit. Mating disruption, using sex pheromones, represents one promising option for pest management with reduced insecticidal inputs for apricots. Two pheromone blends were used: one, designed to disrupt the two endemic species, was (Z)‐5‐tetra‐decenyl acetate and (Z)‐8‐tetradecenyl acetate, (25:75) and the other, for E. postvittana, was (E)‐1 1‐tetradecenyl acetate and (E)‐9,(E)‐11‐tetradecenyl‐1 acetate (95:5). No moths of three leafroller species were caught in pheromone traps at the centre of 0.1 ha plots of apricot trees treated with polyethylene tubing dispensers, at 1000/ha, whereas those outside the treated area (70 m distant) continued to catch. In commercial orchards, dispenser blends prevented trap catch and reduced damage in apricots on 1–3 orchards per year over 5 years. Dispensers, insecticides, and combinations of the two were equally effective in preventing damage to the fruit and gave better results than the untreated. Dispensers were not as effective as an insecticide programme at one large site over 4 years, except in the centre of the block. Dispensers were less effective where the tree canopy cover was incomplete and this effect was more important than the size of the area treated. Apricots were successfully exported from a 4.8 ha planting that was protected from leafroller damage by the endemic leafroller pheromone dispensers alone in 1996, and those for E. postvittana and the endemic leafroliers (two different dispenser blends) in 1997. Differences between prospects for the use of mating disruption in summerfruit (stonefruit) and pipfruit (pome fruit) are discussed.