Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2005
Publication Date: 1/1/2006
Citation: Myers, C.T., Hull, L.A., Krawczyk, G. 2006. Early-season host plant fruit impacts on reproductive parameters of the oriental fruit moth (lepidoptera: tortricidae). Journal of Entomological Science. v. 41, No. 1, p.65-74.
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. These studies sought to investigate how OFM reproduction differed between apple and peach, which has historically been considered its more favored host. Over the course of two laboratory studies, it was determined that OFM reared on apple fruit had higher reproductive output than those reared on peach fruit, indicating that apple may actually be a more suitable OFM host. Because of the different development patterns between apple and peach, it is possible that apple blocks are more susceptible to large OFM outbreaks late in the growing season because of this phenomenon. Learning about OFM biology has helped growers and pest management practitioners improve their strategies for controlling OFM by taking different management approaches for the two crops.
Technical Abstract: Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), a cosmopolitan pest of tree fruits, has been a significant pest in the United States since its introduction in the early 20th Century. G. molesta has historically been a major pest of stone fruit. However, since the mid to late 1990's, outbreaks in commercial apple orchards in the eastern United States have become common place. This study examined the effects of larval host, apple vs. peach, on G. molesta reproduction, as a means to better understand G. molesta's increased importance as an apple pest in the mid-Atlantic region. In laboratory investigations, G. molesta adults reared on apple fruit had approximately two-fold higher fecundity than those reared on peach (F = 10.98, df = 3,101, P < 0.001). In two separate studies, when larvae were reared under either crowded or non-crowded feeding conditions, female adult longevity and oviposition period were significantly greater among moths reared as larvae on apple than those reared on peach (2001—P = 0.019 and 0.009, repectively; 2002—P = 0.031 and 0.001, respectively). Female pupal weight was significantly higher in individuals reared on apple than those reared on peach, in both studies (2001 and 2002—P < 0.001). Similar host-influenced impacts on G. molesta reproductive phenomena could affect population dynamics of G. molesta, especially late in the season when apple fruit are a preferred feeding site.