Monday, October 14, 2013

Little Fire Ants

The sting of the little fire ant (LFA) is very painful and produces red welts. With some people, welts last as long as three days with aching pain, and later intense itching. 

LFA are tiny (about 1/16 inch long), pale orange and move rather slowly.  They are highly adaptive. They live in the open or under shade, in areas of 10 inches of rainfall to over 100 inches, they are found from sea level to 1700 feet and can nest on the ground or in trees.  They eat just about anything. They can remain up in the tree, or they may move up and down. They will also infest homes under carpets and along baseboards.

Control Measures
 For controlling LFA, researchers recommend a three pronged attack and a whole property approach; spot treating is inadequate. 
1.  Place ant baits in infested areas.  In general, this is done to control ground nests.  The ants will take the bait back to their nest and share it with others. Baits are the front-line tool for ant control.  This approach should be tried first. Wait a couple weeks before applying barrier treatments. 
2.  Barrier treatments – the application of insecticides (liquid or granular) around areas where ants need to be excluded.  As ants crawl over the treated areas they are killed. The more ground you treat, the better. However, if you want to limit your use of chemicals, treat those areas where you want the most protection, areas most used by people and pets.  
3.  Ants nesting in trees may not be controlled by bait applications. Therefore a foliar insecticidal spray, applied to infested trees and vegetation, is needed.

  •  Suitable baits for Little Fire Ants -For step 1  Amdro, Probait, Maxforce Complete, Extinguish Plus (reported as moderately attractive) and Tango, a new product recently registered in Hawaii. Even though the products Extinguish Pro and Esteem Fire Ant Bait are registered for use on many food crops, they are not highly effective; see website below. Tango, on the other hand, is registered for use on food crops and is very effective and safe.
  • Suitable barrier treatments For step 2  Products with the active ingredient bifenthrin (examples, Ortho Home Defence Max granules, Ortho Home Defence spray and others)
  • Suitable chemicals for foliar spraying and drenching potted plants –  For step 3   Look for the active ingredient carbaryl (examples, Eliminator            Bug Killer Sevin Concentrate, Gardentech Sevin Concentrate Bug Killer  and others)

If you suspect that you may have the LFA, coat a chopstick, or any small stick, with peanut butter and stick several in the ground around your property.  If any ants are caught on this bait, take them to the Hawaii State Department of Agriculture at 16 E. Lanikaula St. in Hilo for positive identification.

In addition to the information presented here and for more detailed information, I refer you to an excellent LFA website It was put together by Cas Vanderwoude, a researcher with the Hawaii State Department of Agriculture.   Furthermore, check out the latest research on Tango. Although this product is expensive, it is thought that applications of Tango may control ants well enough that steps 2 and 3 can be eliminated.  Tango is an insect growth regulator (IGR). This type of product works by preventing the insect larvae from completing their pupation process. It also slows down egg production by the queen. Information and directions for making the new gel bait (Tango) are on the website.