Developing farmers' skills and confidence in the use of Trichogramma ostriniae for European corn borer control in sweet corn, peppers and potatoes

Developing farmers' skills and confidence in the use of Trichogramma ostriniae for European corn borer control in sweet corn, peppers and potatoes

Summary

Numerous research and demonstration trials have shown that releases of the parasitic wasp Trichogramma ostriniae (T.ost) can be an effective management strategy for European corn borer control in sweet corn, peppers, and potatoes. It is time to put the use of T.ost into the hands of farmers. Organic farmers, farmers who do not use conventional insecticides, and high-level IPM adopters all stand to benefit from using T.ost releases as all or part of their ECB management strategy, through reduced crop damage, reduced use of insecticides, or both.

Growers who are trying T.ost for the first time benefit from technical support to help make the decisions needed to get good results. An understanding of pest and beneficial biology, crop phenology, and proper release rates is needed, as well as the organizational skills to make decisions, order and release wasps, and monitor success in a timely manner. We will work closely with a minimum of 30 farmers growing sweet corn, peppers, and/or potatoes in New York, Massachusetts, Pennsylvania, and Virginia. Project staff will visit collaborating farmers each week to work with farmers to track crop phenology, decide on wasp needs for the following week, and decide where and how the releases will take place. Wasps will be supplied by the project for the first year, with farmers sharing costs the second year. Wasps are currently available commercially through IPM Laboratories in Locke, NY.

Objectives/Performance Targets

Of the 35 growers who collaborate with the project during the two years of demonstrations, 25 will purchase and release T. ostriniae for European corn borer control on their own during the third year. Of these growers, 20 will report at least two of the following changes with respect to sweet corn, pepper or potato: improved harvest quality or yield; reduced use of insecticide applications for European corn borer control; reduced labor, fuel, or other costs associated with European corn borer control; increased crop acreage; increased net income; improved customer satisfaction; reductions in European corn borer moth trap captures or infestations compared to previous seasons; increased integration of sweet corn as a rotation crop into vegetable/cover crop rotation plan.

Fifteen growers (of 150) who attend twilight or winter meetings will try T. ostriniae on their farm.

Accomplishments/Milestones

In early winter of 2008, project team members in New York and Massachusetts met with collaborating farmers to learn about their experiences releasing T.ost in 2007. As a result of what we learned from interviewing farmers and conversations among the project team, a decision was in Massachusetts to ship wasps directly to farmers in 2008, and have them place the wasps in the field themselves as a step toward farmers using them on their own in the future. Project team members participated in the first releases on each farm, and farmers released on their own after that. In New York, this approach was already being used. Project team members helped keep track of field development, and the project team leader communicated with each farmer weekly as to which fields the wasps should be released in. We also developed a simple form to help farmers keep track of fields and releases.

During the 2008 growing season wasps were released in sweet corn on 24 farms in New York and Massachusetts, and in peppers on five farms in Massachusetts. In New York, seven of the nine farmers using T.ost in sweet corn in 2007 also participated in 2008, and three new farmers were added. In Massachusetts, nine of 13 farmers from 2007 participated in 2008, and five new farmers were added.

In Virginia, the adoption of a new insecticide in potatoes and a decline in corn borer populations thought to be associated with widespread use of field corn genetically engineered to express Bt toxins made T.ost releases a less attractive option for farmers. To enlist farmers interested in trying Tost releases in peppers an offer was made to subsidize the cost of wasps for farmers ordering from IPM Laboratories, the commercial insectary that is rearing and supplying them. A press release was sent out to farmers and extension staff in Virginia, Delaware, and Pennsylvania. Only two farmers took advantage of that offer in 2008, so we will be extending part of the milestones originally planned for 2008 into 2009. Specifically, we will continue working with pepper growers in areas with ECB pressure to introduce them to the use of T.ost. Work on T.ost dispersal in peppers that will help determine the optimal release points per acre was completed in 2007 and 2008.

Impacts and Contributions/Outcomes

All of the cooperating farmers interviewed in early 2008 reported one or more outcomes, such as reduced insecticide use or improved crop quality, that are in line with the performance targets for the project. All were interested in using T.ost again in the future. Most indicated that they would like more education and support in releasing the wasps before using them on their own. Some farmers needed to see the wasps work well a second year before they felt confident that it was worthwhile to release them.

Collaborators: