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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 #193943
Title: EFFECTS OF ORCHARD HOST PLANTS ON THE DEVELOPMENT OF THE ORIENTAL FRUIT MOTH (LEPIDOPTERA: TORTRICIDAE)

Author
item Myers, Clayton
item HULL, LARRY - PENN STATE UNVERSITY
item KRAWCZYK, GRZEGORZ - PENN STATE UNIVERSITY

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2006
Publication Date: 1/4/2007
Citation: Myers, C.T., Hull, L.A., Krawczyk, G. 2007. Effects of orchard host plants on the development of the oriental fruit moth (lepidoptera: tortricidae). Journal of Economic Entomology. 100(2): 421-430.

Interpretive Summary: Oriental fruit moth (OFM) has emerged as a very destructive pest problem on apples in the eastern United States since about 1998. The reasons for the sudden outbreaks are unknown, but one major hypothesis is that OFM exhibit different biology and behavior on different host plants. Experiments were designed to observe differences in OFM developmental rates between apples and peaches. On both fruit and shoots, OFM larvae developed significantly faster on peach than on apple. While this was true in an overall sense, cultivar variation was significant on apple fruit, and larvae developed on some apple cultivars at a rate more similar to development on peach than to development on other apple cultivars. These different developmental rates would affect the accuracy of developmental phenology models, which are used to accurately apply control tactics at times of the season when they will most efficaciously control active populations. Because OFM has multiple generations per season, control tactics need to be applied when larvae of a particular generation are newly hatched from eggs. These timings are determined by biological models based upon accumulated degree days. Since developmental rates have been shown to be different for apple and peach, different timings are needed for the two crops. If the crops are planted in close proximity, then the grower needs to be aware of the different phonological patterns and time control tactics on both crops for times when OFM will be present.

Technical Abstract: Recent population outbreaks of Oriental fruit moth, Grapholita molesta (Busck) (OFM) (Lepidoptera: Tortricidae) have caused significant economic hardships for fruit growers and processors in the mid-Atlantic region. Historically, efforts at OFM control in the eastern U.S. have been most intensive on peach, but in recent years, increased incidents of outbreaks in commercial apple orchards occurred. One possible explanation for outbreaks in apples could be changes in OFM phenology and population dynamics caused by the choice of host plant. Studies were designed to examine the effects of host plants on OFM development. OFM larvae were found to develop faster on peach than on apple, both at fruit feeding sites as well as on growing terminal shoots. On fruit, these differences were shown to cause significant changes in both the rate and pattern of adult emergence between several cultivars of both peaches and apples. These host-driven effects could impact the efficacy of traditional pest management approaches and may impact efforts to predictively model OFM populations in commercial, mixed cultivar orchards. Such developmental effects may also help to explain previously observed differences in pheromone trap capture patterns between peach and apple sites. Host-associated effects should be incorporated into future models to develop more realistic predictive tools and thus improve integrated pest management efforts.