Safe chemical repellents to prevent the spread of invasive ants

The red imported fire ant, Solenopsis invicta, is one of the most dangerous invasive species in the world. Fire ants can spread by hiding among plant material and soil that are transported from infested areas in vehicles and vessels. Therefore, efficient repellents may be used to prevent fire ants from infesting transported goods. Although some fire ant repellants have been identified, novel, cost-effective and environmentally friendly materials for fire ant control are still needed. Recent studies with other model insects have suggested readily available, non-toxic alternatives (e.g., anthranilates) to commercial repellents.We measured the repellent effects of the food additives ethyl anthranilate and butyl anthranilate against nesting by fire ant workers, and the results demonstrated that extremely low concentrations of these compounds can prevent fire ant nesting in pots. The tested compounds remained active at concentrations < 100 µL/L, which is many times lower than the minimum active concentration of any other proposed compound, including the established insect repellent N,N-diethyl-3-methylbenzamide (DEET).These inexpensive chemicals are safely used by the food and cosmetics industries, and their high efficiency differentiates them as the most promising chemicals for use in preventing the spread of fire ants; thus, these chemicals should be evaluated for further potential applications. © 2018 Society of Chemical Industry.