- Author: Anne E Schellman
As weather cools, you may notice ants coming indoors. Large numbers of ants may invade your kitchen, bathroom, garage, bedrooms, or even your living room! Spraying the offending ants with a pesticide or household cleaner (not recommended) may kill the ants you see, but it won't stop more from invading.
Why do ants invade?
Ants are looking for food, water, and sometimes shelter. They live in colonies composed of worker ants and reproductive ants. The workers leave the nest to “scout” for resources. As they travel, they leave a scent trail for other ants to follow. Once food or water is found and that information is communicated to the colony, more ants arrive to help gather the resource.
Prevention
Your first step is to find out where the ants are coming from. Follow their trail until you find where they are entering. Then, use a caulking gun to seal up the cracks.
Sanitation
Is someone in your household inviting the ants? They may unknowingly do so by leaving sandwich crumbs or other foods on your kitchen counters. Pet food is also enticing to ants. Consider feeding your pets and then removing the food. Or, place your pet's food bowl in a larger bowl of water to create a “moat” that ants can't cross.
Management
Wipe up invading ants and their trails with soapy water. This destroys the scent trail left behind that helps attract more ants and kills the ants that are present.
If you've followed all the directions above but ants continue to invade, you may need to use bait to manage the infestation. Baits are a combination of insecticides mixed with a material to attract ants. When ants take the bait, they taste it and pass it along. The insecticide builds up in the system of the worker ants and the queen, eventually killing them. The bait is slow-acting, so it may take a while to see a reduction in ants. If you choose to use a bait, make sure to follow the directions on the label for best results.
For more information about ant management, visit the UC IPM website to read the Ants Quick Tips card from UC IPM. You can also call the Master Gardener helpline at 525-6802 or send us a message at ucmgstanislaus@ucanr.edu.
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The University of California Cooperative Extension (UCCE) Stanislaus County Master Gardeners are available to answer questions on Wednesdays from 9:00 a.m.-12:00 p.m. Drop off a pest or gardening problem sample anytime during business hours to the Stanislaus Agricultural Center at 3800 Cornucopia Way Suite A in Modesto, 95358, and we will get back to you.
Every summer, a handful of insect pests can become a real nuisance when they invade your space, bite, or sting you. Whether you take a staycation or a vacation, you'll want to watch our videos for tips on how to deal with these pests when you encounter them.
1 Ants: What to do if you have an ant emergency
2 Bed bugs: Don't bring bed bugs home when you travel!
3 Mosquitoes: Protect yourself from mosquito bites
4 Yellowjackets: How to reduce yellowjackets in your yard
For more help dealing with these and other home or garden pests, visit the UC IPM web site.
/h2>/h2>/h2>/h2>/h2>/h2>Ants often enter buildings seeking food and water, warmth and shelter, or refuge from dry, hot weather or flooded conditions. They may appear suddenly in buildings if other food sources become unavailable or weather conditions change.
One such ant we see headed indoors during rainy conditions in California, is the Argentine ant. The Argentine ant is about 1/8 of an inch long and dull brown in color. It's normally found living in the landscape in shallow nests, and might even be living just outside your building. When rainy weather floods their nest, Argentine ants may use your home or office as a warm and dry place to relocate.
This rainy season, before ants have a chance to invade your home, be proactive and “ant-proof” your buildings ahead of time Determine what the ants are attracted to and eliminate the food or water source. Monitor the places in and around your home where ants are often found. Follow ant trails to find where they are entering, and seal them off using caulking or other sealants.
Of the 270 species of ants in California, fewer than a dozen are pests, and although ants can be bothersome pests indoors, it's important to remember that outdoors they sometimes also play a beneficial role in the environment.
Visit the Ants section of UC IPM's home and landscape web pages for more information about preventing or managing ant invasions. There you will find videos about ants including, “What to do if you have an ant emergency” and “Why do ants invade?” as well as other resources to help identify ants and know what to do indoors or out.