Crazy ant treatment

August 2004. Crazy ants were intercepted on clean containers that left Vanuatu some time ago. The company that handles the cleaning job in Vanuatu does not want the containers fumigated with methyl bromide as they intend to ship food items in them. Are there alternative chemical(s) that will get rid of the ants, but leave no residue?

If they are empty then steam would be a possibility; alternatively carbon dioxide. It would also be wise clearing the area where packing is occurring – boiling water is useful in killing ant nests. Are the ants coming from the yard where packing is occurring or are they coming in on produce? How long do the containers stay empty? Iis the packing inside or outside, on a concrete floor or wood?

It was also recommended that the container cleaner company treat the problem not the symptom. A baiting program around the cleaning facility (and if possible a buffer zone as well) would lower the likelihood of further container contamination from the surrounds, except for any nuptial flights that may end in the immediate vicinity of the cleaned/uncleaned containers. Baiting would be preferable over spraying, in that there is a greater chance of destroying the whole nest, including the queen, rather than those ants just forgaing on the surface. Drenching the nest with a suitable chemical can also acheive a good result, but relies on being able to find the nest entrance.

MB is generally not residual (unless using MB canisters with added chloropictan), but if you can avoid using this fumigant then so much the better. There are a number of commercial products with little of no residual activity that will kill the ants within the container, but as mentioned this will not get rid of the source of the ants, e.g., sprays with Pestigas (synergised pyrethrum with carbon dioxide as a carrier gas) at 4.4 g/m³ (within an airtight enclosure or fumigation cell) and hold for 10 minutes; or spray with ECO² Fume (phosphine with carbon dioxide as a carrier gas) to give a concentration of 700 ppm a.i./m³ and hold for 15 hours at a minimum air temperature of 15^oC.

Another method of control ants without using chemicals is to apply 2 tablespoons dishwashing soap, 2 tablespoons vegetable oil, 2 tablespoons salt and a few drops of white vinegar in one gallon water. This method of control kills any kind of ant in the CNMI.