Evaluating Entomopathogenic Nematodes for Biological Control of Apple Maggot Fly under Field Conditions

View the project final report

Commodities

• Fruits: apples

Practices

• Education and Training: demonstration, on-farm/ranch research, participatory research
• Pest Management: biological control, integrated pest management

Apple, one of the most valuable fruit crops in the USA, is attacked by many pests. The apple maggot fly (AMF), Rhagoletis pomonella, is a key insect pest in the Northeast. To control AMF, growers typically apply up to three broad-spectrum insecticide sprays to the entire orchard. Foliar sprays target the adult stage. No management options are currently available to kill larvae and pupae of AMF in the soil. Entomopathogenic nematodes (EPNs) have been evaluated as biological agents against many pests. For AMF, two EPN species, Steinernema carpocapsae and S. riobrave, are good candidates. If EPNs prove to be effective at killing the immature stages of AMF in the field, then growers would have another integrated pest management (IPM) tool, which could lead to reductions in insecticide use against AMF in support of more sustainable apple production. In this project, I will evaluate the effectiveness of S. carpocapsae and S. riobrave against the soil-dwelling stages of AMF in three commercial apple orchards. As part of my professional formation, I will be involved in outreach activities with support from UMass Extension. My outreach plan includes one fact sheet, one peer-reviewed research article, one field day at the UMass Cold Spring Orchard, and presentations at regional and national conferences. This project will inform and potentially impact the decision-making of at least 250 apple growers within and outside Massachusetts. Extension and educational outcomes will increase grower knowledge and likelihood of adoption of EPNs to control immature stages of AMF.

The research objective of this project is to evaluate the virulence of the entomopathogenic nematodes (EPN) Steinernema carpocapsae and S. riobrave in commercial apple orchards. In this research I will test each EPN at two different doses of EPN application (high = 200 Infective Juveniles (= IJs) per cm², and low = 50 IJs per cm²), and water only as control (no EPNs).

In the previous research by Pinero et al. 2019 with plum curculio (another apple key pest), they proved that these two nematodes are highly effective to plum curculio in the apple orchard condition. Therefore, if these two nematodes show to be highly effective for apple maggot fly larvae and pupae, we kill ‘two birds with one stone’.