USE OF BAITS AGAINST THE WILD ANT NYLANDERIA FULVA (MAYR) (HYMENOPTERA: FORMICIDAE)

Abstract

Due to the high populations of the "crazy ant", Nylanderia fulva (Mayr) (Hymenoptera: Formicidae-Formici­nae), which cause serious social, eco­nomic and ecological problems, mainly in the coffee-growing region of the Tequendama (Cundinamarca), it was necessary to find an efficient and envi­ronmentally safe control measure, Toxic baits are those which meet best the above-mentioned features since the searching habits of the insect are used to accumulate the lethal dosage, applying in this way a minimum of poison to the environment. The diet of the ant has composed of two parts: a solid one, obtained from ani­ma! protein, and a liquid one, which is procured mainly by ..he honeydew of different sucking ínsects of the order Homoptera. On bases of this knowledge, at the vi­Ilage "Patio Bonito", Municipio de Anapoima (Cundinamarca) during 1980 and 1981, different combina­tions of carriers, attractants and poi­sons, accepted by the ants were tested to obtain an adequate bait to decrease the problems caused by N. fulva. After a series of field trials, a toxic bait for the use of coffee plantations was obtained. This bait, applied atter the rainy season, at the rate of 12 kg/ ha, in coffee plantations without weeds, in bands distanced 10 m, re­presents a solution of the problem of the crazy ant. Comparing this control method with conventional ones, it can be conclu­ded, that it is safer in the environment, specific and more economic, since on­ly 0,112 kg a.i./ha of carbaryl or 0,0825 kg. a.iJha of lindane is used against the conventional dosage of 1,0 to 1,5 kg. a.ilha of the first insec­ticide and 1,0 kg. a.i./ha of the second one, which means a reduction of 8,93 to 13,39 times of carbaryl and 12 Times of lindane applied to the environ­ment. This of course results in a more economic way of control. Regarding specificity, this bait is only attractive to ants with similar feeding habits to those of the crazy ant, being therefore noninjurious to the benefi­cial fauna. According to the LD50 of carbaryl (510 to 850 gr. a.i./kg. weight) and of lindane (88 to 91 gr. a.i./kg. weight), the bait neither would affect domestic animals if they should feed on it.