Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/2/2007
Publication Date: 3/1/2007
Citation: Myers, C.T., Leskey, T.C., Reissig, W. 2007. Fruit susceptibility of malus germplasm to attack from fruit feeding pests: Searching for potential host-plant resistance mechanisms in apple. . Annual Cumberland Shenandoah Fruit Workers Conference.
Technical Abstract: Codling moth (CM), Cydia pomonella L., oriental fruit moth (OFM), Grapholita molesta (Busck), plum curculio (PC), Conotrachelus nenuphar (Herbst), and apple maggot, Rhagoletis pomonella (Walsh) continue to pose significant threats to sustainable apple production in the United States. Research is ongoing to evaluate numerous apple accessions, including both domestic releases and exotic apple and crabapple species from around the world, for potential natural resistance to attack from these insect pests. Prior observations from 2005 have indicated that there is significant variation in pest susceptibility among exotic Malus species housed at the USDA germplasm repository in Geneva, NY. Malus tschonoskii is very resistant to larval feeding by both OFM and CM in the laboratory. Larval survival on fruit of M. tschonoskii was zero or near zero. While M. tschonoskii has some negative horticultural traits that would be obstacles to breeding efforts, there is reason to believe it may possibly be a potential source for genetic resistance to internal feeders. Other Malus accessions, while appearing promising in the field in 2005, had varying susceptibility to internal feeders in the lab and are probably not good sources of genetic resistance. Several cultivars from the Purdue-Rutgers-Illinois (PRI) apple breeding program released with claims of insect pest resistance, are actually not resistant to attack from PC, AM, CM, or OFM. These claims need to be revised in both the horticultural literature and in USDA’s online germplasm database.