Screening for resistance in apple cultivars to lightbrown apple moth, Epiphyas postvittana, and greenheaded leafroller, Planotortrix octo, and its relationship to field damage

Abstract

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.

Differential susceptibility and suitability of domestic and wild apple species for a florivorous weevil and its parasitoids

“…The use of resistant cultivars that are less susceptible to herbivores (direct resistance) or that are supporting biocontrol agents (indirect resistance) is a promising alternative approach for pest control (Wearing et al. ; Hogmire and Miller ; Smith and Clement ). Concerning common diseases such as scab (caused by Venturia inaequalis ), fire blight ( Erwinia amylovora ) or mildew ( Podosphaera leucotricha ), cultivars expressing resistance have already been employed successfully, substantially reducing fungicide applications (Fischer and Fischer ).…”

“…Considering resistance to herbivores, however, hardly any appropriate cultivars are commercially available (Hogmire and Miller 2005;Stoeckli et al 2011), although several studies have addressed resistance of different apple cultivars to arthropod herbivores including the apple blossom weevil Anthonomus pomorum (Curculionidae) (Kalinov a et al 2000;Mody et al 2015), several aphid species (Aphididae) (Miñarro and Dapena 2007;Stoeckli et al 2008a) and the codling moth Cydia pomonella (Tortricidae) (Goonewardene et al 1975(Goonewardene et al , 1979Hogmire and Miller 2005;Stoeckli et al 2008bStoeckli et al , 2009a). Furthermore, genes and quantitative trait loci (QTLs) for pest resistance in apple were identified for future markerassisted breeding of resistant cultivars (Roche et al 1997;Wearing et al 2003;Bus et al 2008;Stoeckli et al 2008cStoeckli et al , 2009a.…”

Mechanisms of woolly aphid [Eriosoma lanigerum (Hausm.)] resistance in apple

“…Once the nymphs passed the third instar on this accession, they grew into adults in both experiments. Wearing et al (2003) suggested that slow development, reduced growth and higher mortality of leafroller larvae (Lepidoptera, Tortricidae) on apple cultivars were caused by antibiosis. Moreover, low settlement rate of first instar larvae and low fecundity of adult leafroller moths were caused by the antixenosis properties of the host plant.…”

Excised Leaf Bioassay: Phenotypic Expression of Natural Resistance in Apple against the Obliquebanded Leafroller

“…Wearing et al [61] developed a ranking system based on development time and pupal weight for three species of leafrollers feeding on different apple genotypes.…”