Argentine ants (Linepithema humile) are the most common ants in urban areas of California, and they are the ones most likely to invade your house in large numbers. When you are faced with a huge swarm of ants in your kitchen, it is almost certain to be this species. However, effective control depends on proper identification, so check out the I.D. tips in the references below!
Being such a common problem, Argentine ants are also linked to one of the most significant pollution problems in urban creeks. It turns out that efforts to control Argentine ants with pesticide sprays have resulted in toxic amounts of pesticides in urban creeks all over California. Until a few years ago, the pesticides diazinon and chlorpyrifos were used extensively to control ants around homes, and were found at toxic levels in urban creeks almost every time water quality agencies looked for them. Now that these pesticides have been phased out, we are finding their replacements, pyrethroid pesticides, at toxic levels in sediments in many urban creeks. Stormwater agencies are working hard to let people know about effective alternative methods for controlling Argentine ants.
Key references for controlling Argentine ants in urban areas
University of California Integrated Pest Management (UCIPM) program:
The California Department of Pesticide Regulation provides information on pest management and pesticides, program, publications, and additional infformation.
The Sacramento Stormwater Quality Partnership participates in the Our Water Our World program, that provides pest control information at retail stores and at www.ourwaterourworld.org/Portals/0/documents/pdf/Ants2-11.pdf.
The Sacramento Stormwater Quality Partnership also supports the Water Wise Pest Control Program, in conjunction with UCIPM and the UC Master Gardener Program, that provides provides pest control information.
- Master Gardeners provide pest control advice at (916) 875-6913
- Pest control cards for ants and other pests are available at http://ourwaterourworld.org/.