The mature leaves of 38 apple (Malus domestica Borkh.) (Rosaceae) cultivars were screened for resistance to laboratory colonies of Epiphyas postvittana (Walker) and Planotortrix octo Dugdale (Lepidoptera: Tortricidae) by measuring larval survival and development rate, and pupal weight, in no‐choice laboratory bioassays in early summer. There were few cultivar effects on larval mortality but Nevis 1, A40R04T119, and ‘Sir Prize’ reduced survival of E. postvittana. Effects on development time and weight were correlated, and were integrated into a single measure of resistance Rc. Rc varied greatly between cultivars for both leafroller species, and identified 15 and 11 cultivars with partial resistance to E. postvittana and P. octo, respectively. A further experiment with three of the cultivars in midsummer, using the laboratory colonies in comparison with new colonies (from field collected larvae), produced similar results for E. postvittana, but there was no survival of new colony P. octo larvae on two cultivars. These results for P. octo are consistent with other recent research showing extreme cultivar resistance and critical colony and seasonal influences. A series of 4‐year field trials with the 38 cultivars showed poor correlation between laboratory and field resistance for the dominant leafroller species in the field, E. postvittana. The combined data, however, identified ‘Red Dougherty’, ‘Sir Prize’, and A40R04T119 as potentially useful in breeding for resistance to this species. The implications of these findings for integrated pest management (IPM) programmes and for the breeding of leafroller‐resistant apple cultivars are discussed.

The survival and development rate of Ctenopseustis obliquana (Walker) (Lepidoptera: Tortricidae) larvae, and weight of pupae were measured on detached mature leaves of two apple (Malus domestica Borkh.) progenies derived from the resistant (R) parent ‘Prima’ crossed with the susceptible (S) cultivars ‘Liberty’ (n = 44) and ‘Red Delicious’ (n = 35). The R:S ratio in both these modified backcross families did not differ significantly from the 1:1 expected in the case of monogenic resistance, carried in a heterozygous condition in the resistant parent. The survival to pupation on the individual seedlings was either zero/very low (R) or high (S). With all resistant seedlings being heterozygous, this indicates that the resistance allele shows complete dominance over the susceptible allele. We have named this putative gene Cob1. The expression of the resistance was found to be influenced by both the colony of C. obliquana used and the time of the season when resistance was assessed. In a separate experiment with another tortricid, there was no survival of Planotortrix octoDugdale larvae on the apple cultivar ‘Prima’ and high survival on the cultivars ‘Liberty’ and ‘Red Delicious’. The similarity of the responses of the two leafroller species to these cultivars, and other published evidence concerning Planotortrix excessana (Walker) and Ctenopseustis herana(Felder and Rogerhofer), suggest that the resistance discovered to C. obliquana may be effective against all four endemic tortricid species. The implications of these findings for apple breeding and leafroller control in New Zealand are discussed.

Woolly apple aphid (WAA), Eriosoma lanigerum (Hausmann), and its natural enemies were monitored from 1994 to 2000 on apples at Clyde, Central Otago, New Zealand during the transition from conventional fruit production (CFP), which used broad spectrum insecticides, to integrated fruit production (IFP), which was based on selective insecticides. Populations were compared in orchard blocks under three management regimes: CFP; transition to IFP; and a biological fruit production (BFP) programme which complied with BioGro † organic certification. WAA remained at very low levels in the CFP programme, because of insecticides, and in the BFP programme, primarily because of natural enemies. Transition to IFP was accompanied by a surge in WAA and a slow colonization by natural enemies which took at least four years to reduce the aphid population to acceptable levels. The principal natural enemy that achieved this was the parasitoid Aphelinus mali (Haldemann), assisted by predators whose contribution remained obscure, including the brown lacewing Micromus tasmaniae (Walker) and the European earwig Forficula auricularia L. A single annual application of lufenuron within the IFP programme was not detrimental to any of these natural enemies, although further research is needed to confirm its lack of impact on the lacewing. Lufenuron reduced arboreal predator diversity, as measured by the Shannon-Wiener index, and this was in part due to decline in the populations of the generalist predator Orius vicinus (Ribaut) and the coccinellid mite predator Stethorus bifidus Kapur. Pirimicarb was an effective selective aphicide for integration with the action of the natural enemies of WAA, but a substitute is required, as its use is no longer permitted on export crops. The implications of these findings for the management of WAA in IFP are discussed.

Deployment of single dispensers into commercial stone fruit orchards led to disruption of trapping for the three species and measurable reductions in insecticide use in cherries, peaches and nectarines without increased fruit damage (assessed in apricots).

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