Leafroller oviposition on larval host plants

Caged greenheaded leafroller (Planotortrix excessana (Walker)) (Lepidoptera: Tortricidae) and lightbrown apple moth (Epiphyas postvittana (Walker)) (Lepidoptera: Tortricidae) adults were provided with the leaves of known larval host plants to determine the relative amount of oviposition on the different hosts. Relative to apple leaves, lightbrown apple moth oviposited fewer eggs on narrow-leaved plantain (Plantago lanceolata L.), and blackberry (Rubus strigolosus agg.) and equal numbers on poplar (Populus nigra L.). Greenheaded leafrollers laid more eggs on poplar leaves than on apple leaves. Close examination of the likely factors determining oviposition sites revealed that hairs on the dorsal leaf surface could affect the choice of oviposition sites. Lightbrown apple moths therefore tended to oviposit more frequently on the less hairy mature leaves of apple shoots compared to more hairy, emerging leaves which had a greater density of dorsal surface leaf hairs. Arrangement of host plant leaf clusters may have affected oviposition site preference as lightbrown apple moths tended to lay relatively more eggs on apple fruiting clusters than shoots.