Project Number: 8080-21000-030-01-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2018
End Date: Aug 31, 2021
The objectives of this project are to: 1) evaluate the stage-specific susceptibility of R. pomonella to entomopathogenic nematode (EPN) species/strains under laboratory, semi-field and field conditions; 2) optimize an attract-and-kill system for apple maggot fly (AMF) involving odor-baited attracticidal spheres; 3) integrate attract-and-kill with biological control for insecticide-free management of AMF; and 4) extend research findings to growers and extension personnel.
To assess the relative susceptibility of AMF larvae versus pupae to the various EPN species/strains, the following immature stages will be exposed: 1) third-instar larvae, 2) six hours after larval exit (pre-pupa), 3) one-day old pupae, and 4) three-day old pupae. Plastic cups will be filled with 20 g of oven-dried soil from Massachusetts that will be watered until reaching field capacity. Approximately 500 IJs of a particular EPN species/strain will be applied to each cup in 0.5 ml tap water. Controls will receive water only. Afterwards, one AMF larva (third instar) will be added to each cup. Cups will be stored at 20°C, and survival of R. pomonella will be recorded at five and 12 days post-treatment. The same approach will be used to expose pre-pupa (six-hour-old), and pupae (one and three days old). Evaluation of the two most effective EPNs will be conducted at four sites: 1) apple orchards located at the Appalachian Fruit Research Station, Kearneysville, WV, 2) University of Massachusetts Cold Spring Orchard site near Belchertown, MA, 3) orchard in the proximity of the University of Connecticut, Storrs, CT, and 4) research station of the University of Rhode Island, Providence, RI. Each plot will receive a mini-plot cage which will be buried to 15 cm deep. One hundred third instar AMF larvae will be added, and each cage will receive one of three treatments: 1) EPN species A, 2) EPN species B, and 3) control (AMF larvae but no EPNS). After nematode application, a capturing device will be placed on each PVC cage to capture emerging AMF adults. To compare the degree to which butyl hexanoate and the 5-compound ester blend results in aggregation of AMF injury to baited trees, relative to unbaited trees, we will conduct experiments at the University of Massachusetts Cold Spring Orchard. One perimeter row will be subdivided into three sections of 15 m. One central apple tree per section will receive one of the following treatments: 1) one low-density polyethylene (LDPE) vial with 2 ml of the 5-compound blend [composition: butyl butanoate (10%), propyl hexanoate (4%), butyl hexanoate (37%), hexyl butanoate (44%), and pentyl hexanoate (5%)], 2) one LDPE vial loaded with 2 ml of butyl hexanoate (attractant that preceded the development of the 5-compound blend), and 3) unbaited tree. Once a week, one unbaited 8 cm red sphere coated with Tangletrap® will be deployed for 24 hours to capture adult AMF foraging within tree canopies. We will also evaluate the mortality effects of erythritol as a toxicant in attracticidal spheres at four concentrations. In year three, field scale-studies involving use of the attract-and-kill + EPN method versus grower control involving insecticide sprays will be conducted in Massachusetts commercial orchards. A multi-dimensional outreach program has been designed to disseminate project results among stakeholders within and beyond Massachusetts, including on-farm demonstrations, twilight meetings, fact sheets and video clips.