Resumen

BERTORELLI, M.V.; MONTILLA, J  y  HERNANDEZ, J. Defoliation effect caused by leaf-cutting ants (Formicidae:Attini) on cassava (Manihot esculenta CRANTZ) yield. Rev. Fac. Agron. [online]. 2006, vol.23, n.3, pp.310-318. ISSN 0378-7818.

Leaf-cutting ants cause severe damage in cassava crops especially in the plantation establishment phase; however, there is little information about the species that attack the crop and the effect on cassava yield. With the purpose of identifying leaf-cutting ants species in the studied crop and their effect on the yield, 6 experimental plots of "Venezuela 7", a commercial clone, were established at INIA experimental field, El Tigre, Anzoátegui state, Venezuela. Two treatments were applied in the trial (treated plots with insecticides and no-treated plots) each with three replications. Insecticides were applied to all active nests, which were numbered and identified. The plots were evaluated every 21 days from June 2001 to May, 2002, and the number of damaged plant in each replication was registered. The results determined the presence of Acromyrmex landolti F., and Atta sexdens L. in the evaluated plots. From the total nest located in the non-treated plots 73% belongs to Atta sexdens species and 27% to A. landolti. A. sexdens was the most abundant in the studied area and the only one that caused defoliation in the crop. In relation to the number of damaged plants, significant differences between treatments were observed with a greater damage in the non-treated plots which caused 55% lost in the yield of the crop.

Palabras clave : Leaf-cutting ants; Atta; yield; Manihot esculenta.