Cowpea weevils are very small – coming in at about 2 to 5.4 millimeters long. They are so small that you are better off having a Board Certified Entomologist identify them to see if you need a weevil exterminator. They are brown in color with wings that have black markings on them. The cowpea weevil’s wings do not cover their entire abdomen, so those black markings are also visible on the end of their abdomen, as well.
Cowpea weevils are known as “internal feeders.” The female deposits eggs on the developing pod or on the surface of stored beans. The larvae bore into the bean and begin to eat. A seed can support more than one larva at the same time. The larvae stay inside the bean during the entire life cycle and emerge as adults. If beans are stored in a warm, humid place, the life cycle can be completed in as little as three weeks. Adult cowpea weevils will lay eggs on the same beans where they developed.
Where do cowpea weevils live?
Adult cowpea weevils may be found outdoors in flowers in early spring. Eggs laid by females hatch in 5 to 20 days. Larvae typically feed inside the cowpea, taking from 2 weeks to 6 months to develop before pupating there. Six or seven generations may occur per year. Mouthparts are for chewing. They prefer dried cowpeas but will attack other beans and peas in storage. Adults move about readily and can infest seeds in the field, but can also breed continuously in stored dry cowpeas. Larvae typically develop inside the dried peas. Larvae chew near the surface and leave a thin covering uneaten which appears as a window. Later the adult emerges from the “window.” So they go where the beans are, basically.
How did I get cowpea weevils?
Since cowpea weevils tend to infest dried beans, you could unwittingly and unknowingly bring them home with you from the grocery store. They tend to infest beans at the source rather than sauntering into you home in search of them. So, it’s most likely nothing you did wrong. Eliminating an infestation of cowpea weevils in a home begins with a careful inspection. Find all of the food that shows signs of cowpea weevils activity. Discard all of the infested products. Vacuum the pantry and cabinet shelves thoroughly to be remove any adult insects and be sure to empty out the vacuum so that you aren’t just storing them there for a future infestation. As the infestation grows, some of the adults may fly toward the windows. These adult weevils at the windows and the beans with holes are signs that there is an infestation. Infestations in homes can come from beans grown in the garden or from packaged beans from a store so make sure you inspect your garden’s bounty before bringing it in.
Cowpea weevils not only eat and ruin dried beans in your pantry or food storage areas, but they also lay their eggs in them, so the larvae have something to eat as they hatch and mature. Adults tend to fly toward windows leaving you to mistake them for the common fly. At the end of the day, it doesn’t matter where you got them, you just need them out of your pantry before they can take a bite out of any more of your dry goods or your bottom line. Bring in a professional pest control company to not just identify the weevil you’re seeing but to provide you with the appropriate weevil treatments to achieve weevil control.Not the weevil you have?
How can I prevent cowpea weevils?
Storing new products in sealed containers can help to prevent future cowpea weevil problems. Unfortunately, getting cowpea weevils in your pantry means you probably brought them in with you from either your garden or in a bag of dried beans from the grocery store. Thoroughly wash your garden’s bounty in the sink before storing it anywhere. Unfortunately, preventing bringing home a bag of beans with these weevils is harder than it sounds. They are pretty tiny and unless you’re an Entomologist (like the ones that work for us), it will be hard to see the tell-tale signs which include damage appearing as round holes in the peas. Be sure to thoroughly clean and vacuum your pantry if you see signs of a cowpea weevil infestation.
We’re passionate about keeping weevils out of your home or business because we live and work here – it’s our neighborhood, too. With our 130 years of experience keeping homes and businesses in Massachusetts, Connecticut, New York, Maine, Vermont, New Hampshire, and Rhode Island safe from pests, Waltham has the experience you can trust.