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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 #193949
Title: Effects of Orchard Host Plants on the Oviposition Preference of the Oriental Fruit Moth (Lepidoptera: Tortricidae)

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

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2006
Publication Date: 8/1/2006
Citation: Myers, C.T., Hull, L.A., Krawczyk, G. 2006. Effects of Orchard Host Plants on the Oviposition Preference of the Oriental Fruit Moth (Lepidoptera: Tortricidae). Journal of Economic Entomology. 99: 1176-1183.

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 see if OFM exhibited a preference for egg-laying on either peach or apple, and if such preferences vary over the course of a growing season. Over three years of study in the field, OFM adults preferred non-bearing peach trees to non-bearing apple trees for laying eggs. This was the case regardless of the host origin of the OFM population, indicating that there is no conditioning effect for OFM to prefer the host from which they came. In an orchard scale study, OFM again preferred peach trees for oviposition during the early part of the season. However, as peach fruit were harvested and apple fruit began to mature, OFM preference shifted to apple late in the growing season, and total egg laying on apple fruit was very high. This data indicates that growers with peach and apple blocks grown in close proximity need to be aware how insect dispersal may affect OFM populations. Control tactics may need to be prioritized on peach in the early season and on apple in the late season. OFM adults likely leave nearby peach orchards near the end of summer and begin inundating susceptible apple trees with eggs late in the growing season. Such information is critical for applying control measures in a way that will have the most efficacy and efficiency.

Technical Abstract: Recently, the Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has emerged as a major problem on apples grown in the mid-Atlantic and mid-western U.S., despite its historically important and frequent occurrence as a peach pest. It is possible that host-driven biological phenomena may be contributing to changes in G. molesta population dynamics resulting in outbreaks in apple. Studies were designed to examine the effects of host plants on oviposition behavior, in an effort to clarify the host-association status of eastern U.S. populations, and also to gain insights into how pest modeling and management efforts may be altered to take into account various host-associated effects. G. molesta adults exhibited ovipositional preference for non-bearing peach trees over non-bearing apple trees in close-range choice tests conducted in the field, regardless of the larval host-origin. A significant preference for peach shoots over apple shoots was observed on six of twelve sampling dates with a wild G. molesta population at the interface of adjacent peach and apple blocks. Numbers of eggs found on apple fruit were higher in the later part of the season after peach fruit were harvested and apple fruit began to approach maturity during the period of flight for 3rd and 4th brood adults. Possible implications for population modeling and integrated management of G. molesta are discussed.