Summerfruit tοrtriχ, Adoxophyes orana: life cycle, warning system and control

Abstract

The summerfruit tortrix, Adoxophyes orana F.v.R., is a pest which has recently adapted to the intensive culture of apple and pear. The larvae develop primarily on the young leaves and shoots and occasionally feed on the surface of the fruit. Under Swiss conditions there are two flights per year though there are three in Greece with the second and third overlapping. The diapausing larvae hibernate in the third stage (L3) and begin development again in the spring. There are three periods in which the larvae are active. The methods used to sample populations for making management decisions are: visual examination of flower clusters in spring, sex pheromone traps, and visual examination of shoots and fruit in summer. A model describing the life cycle as a function of temperature allows for the determination of the best time to sample damage and to apply treatments with regard to their particular mode of action. Some classical insecticides provide control curatively but efficiency is always reduced against older larvae. The best results are obtained at egg eclosion following the first flight. The insect growth regulator (IGR), fenoxycarb, is very effective when applied in the spring against the last stage larvae (Ls) of the overwintering generation. A specific virus also gives good control in the spring against overwintering larvae. The mating disruption technique and insect growth inhibitors (ICI), which prevent the formation of chitin, are currently being studied. For all the products used to control A. orana, the timing of the application is extremely important in order to obtain the best