Topical Toxicity of Esenbeckia pumila Extracts on Leaf-Cutting Ants Atta laevigata and Acromyrmex balzani

The aim of this study was to evaluate the topical toxicity of the Esenbeckia pumila plant extracts on workers of the Atta laevigata and Acromyrmex balzani. Five leaf fractions E. pumila were drawn viz., the hexane, ethanolic, dichloromethane, ethyl acetate and methanolic extracts, as well as the ethanolic fruit extracts. Further, the phytochemical leaf extract exploration was performed, and the secondary compounds detected were as follows: flavonoids, anthraquinones, coumarins, cardioactive heterosides and tannins. The different leaf and fruit extract fractions were first diluted in 70% ethyl alcohol, and different doses were topically applied to the A. laevigata and A. balzani workers. All the fractions extracted exhibited formicidal effects and this effect was greater to A. laevigata rather than to A. balzani. Only a small percentage of the workers succumbed within the first few hours of application of the different extracts in comparison with the workers which died only after a longer exposure time (72 h) implying a delayed effect of E. pumila extracts.