Wasps that carry grass, whose scientific name is Isodontia, are a common pest that can build nests near homes. Even though they aren’t dangerous, their dried grass nests can be ugly and annoying to clean up every time. If you find grass-carrying wasp nests around your home in window frames, door frames, vents, or other cracks, here are some ways to get rid of them and keep them from coming back.
Understanding Grass Carrying Wasps
The female grass carrying wasps carry blades of grass to build their nests, which is how they got their name. There are five or six species in North America. Most of them are black or reddish brown and 12 to 20 mm long.
The wasp’s life cycle starts in early summer, when the adults come out of their cocoons and the females start looking for places to nest. They like places that are tight, like window tracks, folded patio umbrellas, old carpenter bee nests, holes in soil banks or rocks, pitcher plants, and bee hotels.
Once a suitable cavity is found, the female wasp will begin packing it tightly with dried grass, using chewed up saliva to stick the grass together. She lays a single egg within each cell and provisions it with captured and paralyzed katydids, tree crickets or other orthopterans for her young to feed on once they hatch.
The larvae are yellowish grubs with no legs that grow eating the captured insects. They eventually form an oval, papery brown cocoon, inside which they pupate before emerging as adult wasps in early summer to restart the cycle.
Why Get Rid of Grass Carrying Wasp Nests?
Wasps that carry grass are not mean and don’t sting very often, but their nests can be a bother:
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They frequently build nests in window tracks, clogging them up and preventing windows from properly opening and closing.
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Repeatedly cleaning out dried grass from the same areas over and over can be annoying.
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The larvae feeding on captured insects can leave behind cricket carcasses and other insect parts.
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Abandoned nests with dead larvae or cocoons look unsightly.
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Over time, build up of nesting materials in certain areas could promote rot or moisture damage.
For these reasons, it’s often desirable to remove grass carrying wasp nests and deter the wasps from repeatedly nesting in the same areas around your home.
How to Get Rid of Grass Carrying Wasp Nests
Getting rid of existing grass carrying wasp nests is straightforward. Here are some tips:
Manual Removal
Simply use a stiff brush or old toothbrush to scrub out any dried grass and nesting material from window tracks or other areas wasps have been nesting. Look for larvae, cocoons or cricket carcasses and remove any you find. Vacuuming the areas afterward is also a good idea to pick up any remaining debris or grass pieces.
Seal Up Nesting Sites
Once you’ve cleared out any existing nests, deter future nesting by sealing cracks and gaps so the wasps can’t rebuild in the same areas. Use weatherstripping, caulk, insulation or other materials to close up openings around windows, doors, vents and other crevices. Plugging holes in outdoor surfaces like soil banks, rocks, or block walls can also help reduce nesting spots.
Remove Food and Water Sources
Make your home less attractive to grass carrying wasps by eliminating outdoor food and water sources. Fix leaky faucets, clean up fallen fruit from trees, and remove bird baths or pet dishes that aren’t being actively used. Installing fine mesh covers over rain barrels or buckets can allow you to keep water outside while preventing wasp access.
Use Repellents
Insect repellents made with mint, lemongrass or citronella oils can help deter grass carrying wasps. Apply these oils around doors, windowsills and other common entry points. Be aware repellents may need reapplication after heavy rain.
Call a Pest Control Professional
For severe infestations, bringing in a licensed pest control professional may be warranted. They have access to long-lasting synthetic repellents and insecticides as well as foam/sealant products that can provide a more permanent seal in problem nesting areas.
Prevention Tips
Preventing grass carrying wasps from nesting in the first place is ideal. Here are some tips:
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Keep screens in windows and doors in good repair, with no gaps or holes.
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Check window tracks and window sills frequently and clean out any nest starts before they are completed.
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Reduce clutter around the home that creates crevices for nesting, like piles of debris, deep mulch beds, unused flower pots, etc.
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Clean out bee houses or nest boxes intended for solitary bees which wasps may try to occupy.
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Seal any openings in soffits, vents, attic fans or cracks in siding.
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Caulk and seal wall cracks, holes or crevices on outdoor surfaces.
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Keep ground cover trimmed back from the foundation. Prune any shrubs or bushes touching walls.
By taking some time to proactively seal, clean and organize problem areas around your home, you can discourage grass carrying wasps and enjoy your outdoor space pest-free. Monitor for any new nests and promptly remove them before wasps have a chance to complete them. With vigilant prevention and removal of nests, you can stop grass carrying wasps from becoming a perennial nuisance around your home.
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Thanks for reading! If you want to know more about how to get rid of pests, read our full interview with Chris Parker.
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- 1 Learn about ground digger wasps. Ground-digger wasps (GDWs) are very big wasps—slightly bigger than a green hornet—that “build” their nests in dry, unfertilized ground. They are usually big, black, and have yellow stripes on the back of their bodies. They are at least 1.5 inches long and have wings that are about 1/4 inch wide when they are fully grown. [1] .
- 2. Know how to tell if ground digger wasps are living in your garden or lawn. […] You’ll know you have ground-digger wasp nests when you see small, granular piles of dirt that are two to five inches high. A hole about the size of a finger will be at the base of the pile of loose dirt, and a “path” of dirt will go out of it. The nests will be built all over your lawn or garden, but most of the time they will be in the driest spots, under long grass or weeds, or under flowers that are growing. GDWs do not like, but can live in, moist soil. Advertisement .
- 3 Find out the local life cycle. Ground-digger wasps have a one-month life cycle that starts in the middle of July and ends in the middle to late August in the Northeast US. Their life cycle may start earlier or later depending on where you live. In about two to three weeks, they grow up from young adults who are excited about play-attacking with each other to full-grown adults. [3] .
- 4. It’s important to know that they only sting when they’re scared. Even though they look very scary, they are passive stingers, which means they will only attack and sting if they feel very threatened. […] It would take you almost breaking into their nests while they’re flying around for one to sting you, so don’t do that! Otherwise, they’ll likely buzz around to check you out and scare you away, which is likely to happen the first time you see them. Know that they’d rather kill cicadas in the trees than sting you. [5] .
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- 1. This method basically kills the wasps in their nests; there is no other way to get rid of them that is safe for pets nearby. Most likely, you will still get nests every year, but maybe only one or two. It’s best to kill them all in their nests so their young don’t return to the spot where they were born.
- 2 Get the supplies. If you want to get rid of ground-digger wasps (GDWs), you can get a large bag of white plastic knives and up to three or four gallons of regular or lemon ammonia at your local grocery store or party store.
- 3. Mark each nest you find with one of the plastic knives pushed into the ground as close to the hole of the nest as possible during the day, when the wasps are out hunting for cicadas in the trees. Be careful not to damage the hole. Just enough of the knife should stick out so you can see it.
- 4. That night, after 10:30 or 11 p.m. (later is better), find the knives you put there with a flashlight and carefully pour about two to three cups of ammonia into each hole. The wasps are probably sleeping or building a nest right now, so you’ll catch them in the nest. If you mix equal parts water and ammonia, you can make the amount last longer. The diluted strength will still be enough to kill them. ) Do not remove the knives.
- 5. Do the same thing again the next day with any new nests you find in the ground. The knives from the night before will still be in the new nests, so you’ll be able to tell them apart from the old ones. Once youve identified the new nests, remove the old knives. Depending on how many wasps there were to begin with, you may have to do this over and over again. You could also hit the wasps with tennis rackets to knock them down and then step on them.
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- You can choose this option if you don’t mind letting animals follow their natural cycles. For starters, this is a natural cycle that is nature’s way of dealing with a huge number of cicadas. The second great thing about these animals is that you can watch them from your own yard. They’re raising their families, which is something all animals try to do. […] If you leave them alone, it’s easy to deal with: [7] Don’t make them mad. Do not walk on them, poke or push them, or use anything to hurt them. Ignore them for two months. Let them be while they gather cicadas to feed their kids. After two months, theyll be off. Dont wander around with bare feet at night. When you walk in your garden, be careful. No yard is completely free of prickles, stings, and other unpleasant things, so wear the right gear and use your yard in a smart way.
How To Get Of Grass Carrying Wasps: Easy Tips
FAQ
What kind of wasps build nests with grass?
Grass-carrying wasps (Isodontia mexicana) are known for building nests using dried grass. These wasps, which are solitary and belong to the family Sphecidae, gather grass and other plant fibers to line and divide their nests. They do this by using window tracks, hollow stems, or old insect burrows that have been abandoned.
Are grass-carrying wasps aggressive?
Grass-carrying wasps are generally not aggressive and rarely sting humans. They are solitary wasps, meaning they don’t live in colonies and are not defensive of their nests.
Why are wasps landing in my grass?
Wasps flying over your lawn could be attracted for several reasons, especially after you’ve added fertilizer: Food Sources: Many wasps are scavengers and may be searching for food. Fertilizers can sometimes attract insects, which can in turn attract wasps looking for a meal.
How to get rid of lots of wasps in grass?
Soap and Water: Mix two tablespoons of dish soap with water in a spray bottle. Spray directly on the wasps and nest. The soap clogs their breathing pores. Peppermint Oil: Mix peppermint oil with water and spray it on the nest. Wasps dislike the smell and may leave.