Leafroller (Lepidoptera: Tortricidae) damage to buds of raspberry canes in New Zealand

Abstract Leafroller larvae on raspberry (Rubus idaeus) canes at budburst were most often found in the most fruitful region of the cane (0.6–1.6m above ground level). Larvae usually destroyed both primary and secondary buds. Simulated larval damage at budburst and possible compensation by the cane was investigated by manually removing different numbers of buds. Canes compensated by producing more fruit per remaining lateral, but only following bud loss of 25%. Larval damage in most commercial raspberry gardens rarely exceeded 5%, so yield loss was directly related to bud loss. An economic assessment snowed that a single application of azinphos-methyl would be cost effective in gardens producing fruit for export if only one bud per 30 m of hedgerow of commercial raspberry planting was infested with leafroller. Such damage levels were frequently found.