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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #211459
Title: Susceptibility of fruit from diverse apple and crabapple germplasm to attack from apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae)

Author
item Myers, Clayton
item REISSIG, W. HARVEY - CORNELL UNIVERSITY
item Forsline, Philip

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2007
Publication Date: 2/1/2008
Citation: Myers, C.T., Reissig, W., Forsline, P.L. 2008. Susceptibility of fruit from diverse apple and crabapple germplasm to attack from apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae). Journal of Economic Entomology. 101:206-215.

Interpretive Summary: Apple maggot (AM) is a destructive direct pest of apples in eastern North America. AM is controlled primarily through the use of chemical insecticides, and damage from AM is a significant obstacle to sustainable apple production. Prior research has lead to questions regarding the potential for host-plant resistance to apple maggot. Studies were designed to evaluate various domestic and exotic Malus accessions housed in USDA’s germplasm collections, and to determine the potential for possible development of cultivars resistant to AM. A number of apple hybrid selections have been previously released with claims of resistance to apple maggot; however, we determined that these claims were erroneous. All accessions we observed were quite susceptible to oviposition attack from apple maggot adults. However, one particular selection, ‘E36-7’ appears to be very resistant to feeding by apple maggot larvae. This late maturing selection appears to exhibit resistance that is tied to factors beyond fruit development and maturity, and may be expressing phytochemicals that are toxic to AM larvae. Similarly, larval survival was zero or near zero on fruit from a number of exotic crabapple accessions that were assessed in the laboratory. Further research is necessary to determine the mechanisms underlying this observed resistance and to determine if such traits could be incorporated into commercially appealing apple cultivars.

Technical Abstract: Apple maggot, Rhagoletis pomonella (Walsh) is a pest of major concern to apple, Malus x domestica (Borkh.) production in eastern North America. Host-plant resistance to apple maggot among apple germplasm has been previously evaluated among a small number of exotic Malus accessions and domestic hybrid selections. However, a large number of exotic accessions housed in USDA collections have never been evaluated for their susceptibility to apple pests. Additionally, previous reports of resistance need to be confirmed under both field conditions with more rigorous laboratory evaluations. Thus, studies were conducted to evaluate the susceptibility of a number of Malus accessions housed at the USDA Plant Genetic Resources Unit (PGRU) ‘core’ collection. Contrary to earlier published reports, these results suggest that some selections previously described as ‘resistant’ are in fact susceptible to both oviposition damage and larval feeding damage by apple maggot. One domestic, disease-resistant apple accession, ‘E36-7’ is resistant to survival of apple maggot larvae except when the fruit is nearly ripe in late fall. While adults can successfully oviposit on all accessions examined, larval survival was zero in a number of small-fruited crabapple accessions classified as resistant in previous studies and in two accessions, Malus tschonoskii, and M. spectabilis, that have not been previously evaluated.