1a. Objectives (from AD-416)
We will: (1) isolate and identify attractive olfactory stimuli associated with host-and mate-finding for adult plum curculio using gas chromatography coupled with electroantennogram dected and mass spectrometry; (2) develop effective deployment strategies for newly identified olfactory stimuli to manipulate host- and mate-finding and promote aggreagation of the plum curculio within apple orchards; (3) evaluate efficacy of entomopathogenic nematodes against plum curculio larvae; (4) evaluate efficacy of a multi-lifestage approach for management of plum curculio within spatially precise locations within commercial apple orchards; and (5) actively promote outreach and information exchange among interested stakeholders, crop consultants, state IPM research and extension programs, and federal researchers.
1b. Approach (from AD-416)
We will utilize laboratory-based electrophysiological studies and field-based bioassays to identify novel olfactory stimuli for the plum curculio. We will also perform laboratory and field-based studies to identify effective entomopathogenic nematodes. Final evaluations will be made in commercial orchards.
3. Progress Report
At two grower orchards in Massachusetts, a designated block was divided into two ~2.5 ha plots to compare the trap-tree management strategy with grower standard whole-plot insecticide spray programs. All trap-tree treatment plots were established during late bloom and geo-referenced. Two trap tree treatments were established: 1) benzaldehyde dispensers deployed in association with pheromone dispensers containing grandisoic acid or 2) benzaldehyde dispensers, pheromone dispensers containing grandisoic acid, and an additional stimulus, trans-2-hexenal. At petal fall, growers applied a full block insecticide application. In trap-tree plots, only the trap trees were subsequently treated with insecticide following the full block insecticide application. The grower-standard received insecticide sprays throughout the entire plot. Fruit injury evaluations are currently being made. The total number of fruit with oviposition scars and total number of oviposition scars are being recorded based on a sample of 20 fruit/tree in trap trees (with and without trans-2-hexenal) in the trap-tree plot and flagged control trees in the grower-standard plots, and in peripherally located trees surrounding each trap tree and control tree for a total of up to 6000 fruit per plot. In addition, 20 interior trees (20 fruit/tree) were sampled along diagonal paths from opposing corners of the trap-tree and grower-standard plots to provide a measure of efficacy of each treatment program to protect fruit from plum curculio immigration and injury. A total of 400 interior fruit per plot were sampled. In addition, a semi-field trial evaluating efficacy of promising entomopathogenic nematode strains including S. feltiae and S. riobrave against plum curculio larvae is being conducted in an untreated apple block. Larvae were released into small circular plots, nematode treatments applied, and various irrigation treatment regimes applied. Overall emergence of adult plum curculio will be measured. The ADODR has monitored activities through emails, site visits, and calls.