One of the many benefits of interacting with farmers and land managers is I learn about the problems you face. A question came in around the 17:30 minute mark of how to deal with vole damage problems in their 3- to 5-acre pumpkin patch. I didn’t have an answer regarding registered pesticides (including taste repellents and toxicants) that are labeled for voles in pumpkins. Doing a broad search on the internet is helpful but it is hard to figure out what you can use in your state. Pesticides are often labeled for use in one state but not others. Luckily, anyone can search for registered pesticides online at on the National Pesticide Information Retrieval System. Most states, including Indiana, are included. You can search by EPA registration number, product name, company name, or active ingredient. A particular search can still yield many choices but this is a helpful way of finding out what is available. Each product has a link to the EPA website that includes product labels.
Since our program last week, I did some checking and found a product registered in Indiana labeled for voles in pumpkins as well as many other crops. Millers Hot Sauce is a taste repellent with an active ingredient of capsaicin (2.5% by weight), which is an irritant to animals, but one some people enjoy in hot peppers. Per label instructions adding an anti-transpirant film former or a sticker may prolong the effectiveness of the product. Mix the product and additives with water according to label instructions. For heavy damage, start treatment after first true leaves appear and continue treatment every 7 days. If applying to transplants, start application one week after transplanting and continue every 7 days.
Always read the label completely before applying any pesticide. The efficacy of any repellent depends on a number of factors including animal population size and density, available food, and availability of cover. With voles, the year can be key because their populations tend to cycle. Combining other methods with repellents can often increase success. For example, soil cultivation within plant rows and in adjacent habitat can help reduce the habitat quality for voles. Cultivation can also directly kill some voles. There are of course tradeoffs and every situation is unique. Soil cultivation would not be an option in some cases (e.g., adjacent to water, steep slopes). I was unable to find a toxicant registered for voles in pumpkins. But depending on what the land cover is adjacent to the pumpkin patches, some of these may be appropriate in those areas.
National Pesticide Information Retrieval System
Midwest Fruit Pest Management Guide 2019-2020, The Education Store, Purdue Extension resource center
Hops Production in Indiana: Integrated Pest Management Guide for Hops in Indiana, The Education Store
Turfgrass Insects: Managing Black Cutworms in Turfgrass, The Education Store
Applied Research in Field Crop Pathology for Indiana – 2019, The Education Store
Managing Alfalfa Autotoxicity, The Education Store
Brian MacGowan, Wildlife Extensions Specialist
Purdue Forestry and Natural Resources