The host plant affects the survival of larvae of codling moth Cydia pomonella (L.)(Lepidoptera: Tortricidae)

Abstract: Codling moth Cydia pomonella (L.) attacks both apples and pears in the Netherlands. Insome years, the codling moth infestation on Conference pears seems to occur later in the seasonthan on apple. Experiments were conducted to quantify this difference. Fruits of apple cv. Elstarand pear cv. Conference were artificially infested with mature codling moth eggs from a laboratoryrearing. Infested fruits were confined in fine-mesh bags and sheltered from rainfall. Three weeksafter egg hatch the fruits were harvested and the number of living larvae was assessed. Infestationwas repeated biweekly from June till harvest.Survival of larvae on apple and pear differed dramatically. On apple, success rate of larvaevaried between 30 and 60% during the season. On pear, survival was only 2 to 3% at the beginningof June, and gradually increased when pear fruits matured. Short before harvest the success rate oflarvae on pear equalled the success rate on apple. We conclude that the differences in survival ofthe young codling moth larvae explain the differences between infestation on apple and pear inpractice. The outcome of this work has consequences for the control strategies on Elstar andConference.