Effects of the kairomone ethyl (2E, 4Z)-2,4-decadienoate (DA 2313) on the oviposition behaviour of Cydia pomonella: preliminary investigations

In 2002, 2003, and 2004, semi-field trials on the impact of ethyl (2E, 4Z)-2,4-decadienoate (pear ester), a pear volatile, on the oviposition behaviour of Cydia pomonella L. (Lepidoptera Tortricidae) were conducted. The effects of pear ester applications on oviposition (No. eggs laid) and egg distribution (distance of the eggs from the fruit) were investigated on two crops (apple and pear) on early and late varieties in different phenological stages (fruitlet stage and ripe-fruit stage). The pear ester did not affect the number of eggs laid by C. pomonella females, but it significantly affected egg distribution, favouring oviposition at greater distance from the fruit on late varieties in the ripe fruit stage. In some cases, the pear ester disrupted the oviposition behaviour of C. pomonella females (host location disruption), which could result in higher larval mortality (direct effect) and improve the efficacy of larvicidal insecticides (indirect effect).