Differences in the link between female moth oviposition and larval fitness in Grapholita molesta (Lepidoptera: Tortricidae) over seasonal variation of host fruit species

Abstract

Oriental fruit moth (OFM) is a cosmopolitan borer pest. Adults migrate among peach, pear or apple orchards. However, the association of female oviposition with larval fitness over seasonal variation of fruit species have not been reported. This study investigated female oviposition and larval fitness during four sampling months of peach, apple and pear related with maturity. Infested fruits were investigated in three orchards. These results showed that females laid fewer eggs on apple than peach or pear in June and July, but not May and August. Fitness index of larvae on pear was lower than peach or apple in May, June and August, except for July. In June, larvae failed completely to bore into pear. The ranking of infestation ratio was peach orchard (from June to July) > pear orchard (July onward) > apple orchard (late June onward). Based on the above results, peach (June and July) and pear (July and August) were more suitable than apple (June, July and August), whereas peach (May), apple (May) and pear (May and June) were unsuitable for OFM.