Arthropod Resistance in Plant Introduction Accessions of Malussp. to Some Arthropod Pests of Economic Importance

Abstract

Field evaluations for arthropod resistance were made on 573 Malusaccessions, acquired from 40 countries and growing at Glenn Dale, Maryland. Damage to leaves caused by aphis, European red mite, leafhopper, leafminer and leafroller were recorded. When fruit was present any damage caused by codling moth, fruitworm and plum curculio was noted. To confirm our field observations a total of 297 of the 573 accessions were evaluated in the laboratory or greenhouse. Of the following accessions evaluated in the laboratory were: 168 for apple maggot; 224 for codling moth, 249 for plum curculio; and 261 for redbanded leafroller. Nineteen accessions were evaluated in the greenhouse for European red mite. Accessions were classified as resistant, to apple maggot, codling moth, plum curculio and redbanded leafroller if their resistance levels were significantly (P < 0.05) better than the cv. ‘Jonathan’ and to European red mite if their resistance levels were significatly (P < 0.05) better than the cv. ‘Redfree. None of the cultivars were resistant to apple maggot; 5 were resistant to codling moth; 1 to European red mite; 7 to plum curculio and 4 to redbanded leafroller. Dual resistance was found in: PI 223602 (cv. ‘Mutsu’) to plum curculio and redbanded leafroller; and PI 279645 (cv. ‘Golden Delicious’ x ‘Ingrid Marie’) to codling moth and plum curculio. No laboratory tests were carried out to confirm any resistance to fruitworms, leafhooper and leaf-miner, in accessions lacking field damage by these insects.