Thesis (Ph.D.)--Michigan State University. Dept. of Entomology, 2008. / Title from PDF t.p. (viewed on July 9, 2009) Includes bibliographical references (p. 146-160). Also issued in print.

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Among several early-season insect pests threatening apple production in eastern North America, plum curculio (PC), Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is one of the most devastating pests of pome and stone fruits. Historically, several methods have been used to monitor and control plum curculio in apple orchards. The odor-baited trap tree approach has proven to serve as an effective monitoring and attract-and-kill system for plum curculio. The synergistic lure consisting of benzaldehyde (a plant volatile) and grandisoic acid (the PC aggregation pheromone) is used in this approach. However, the high cost of the lure and the degradation of benzaldehyde by UV light and heat have resulted in limited grower adoption. The major goals of this study were (1) to evaluate under field conditions, the attractiveness of methyl salicylate (MES) to PC, and to determine if it can replace the benzaldehyde (BEN), and (2) to test whether we can manipulate insect pest behavior through host plant preference by grafting selected perimeter- row trees with multiple cultivars. My results indicated that (1) methyl salicylate in combination with grandisoic acid was as attractive to PC as the standard synergistic lure composed of benzaldehyde and grandisoic acid, therefore MES can be used as a replacement for BEN, (2) trees grafted with six cultivars were more attractive to PC and concentrated more PC fruit injuries, compared to non-grafted trees, and (3) ‘Wickson’ and ‘Red Astrachan’ received numerically more PC injuries while ‘Dabinett’ received the lowest level of injury compared with other cultivars. These results highlight that a semiochemical-based strategy is a low-cost and grower-friendly approach to monitoring and controlling the PC population.

Plum curculio, Conotrachelus nenuphar (Herbst), is an endemic pest of stone and pome crops of the eastern United States. Two morphologically identical strains of plum curculio have been described and documented in Virgina: a univoltine strain and a multivoltine strain. Because of the cryptic coloring and behaviours of the plum curculio adults, monitoring in orchards is difficult and often ineffective. RAPD-PCR assay was an effective method for separation of the geographical strains. Of the tested primers four, OPE 01, OPE 03, OPE 04, and OPE 07, gave 21 amplimers that are useful for distinguishing individuals from the univoltine and multivoltine populations. Gene targeted PCR revealed the presence of Wolbachia in both populations. Analysis of the wsp gene sequence showed the univoltine population of plum curculio is associated with a strain of Wolbachia in supergroup B, most closely related to a strain identified from Perithemis tenera (Say) (Odonata). The multivoltine populations of plum curculio are associated with strains of Wolbachia which are in supergroup A, and most closely related to Wolbachia strains associated with Dacus destillatoria, Bactrocera sp., and Callosobruchus chinensis Linn. Three different trap designs baited with grandisoic acid, plant volatiles, and a combination of pheromone and plant volatiles were tested. In 1999, significantly more plum curculios were captured with Tedders traps baited with grandisoic acid and unbaited control in traps baited with limonene, plum essence or ethyl isovalerate. In 2000, Circle traps baited with plum essence, sour cherry essence and grandisoic acid yielded no results. In 2001, branch mimic traps yielded no significant differences among three release rates of a blend of benzaldehyde, ethyl isovalerate, trans-2-hexenal, and limonene; although, there was a significant interaction between the pheromone and the host plant volatiles. Overall however, all three of the traps were not effective. / Master of Science