Interspecific competition between Heliothis virescens (F.) and Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in the chickpea crop (Cicer arietinum L.)

摘要

Systematic samplings were conducted in the chickpea varieties Nacional 29 and JP-94 in three production units of Las Tunas province, Cuba, with a weekly frequency during each crop growing season from 20082011. The relative abundance and frequency of Heliothis virescens (F.) and Spodoptera frugiperda Smith were evaluated on 50 plants per plot in each sampling. S. frugiperda populations were observed to decline in favor of H. virescens. The carrying capacity, the intrinsic rate of increase and the coefficient of competition of both species were determined using the Lotka-Volterra model of interspecific competition. The isoclines generated by the logistic model were determined. It was corroborated that the differences in the abundance of these species on the crop are a response to an interspecific competition for exploitation of resources. The results obtained were the base for the estimation of 0.5 to 1 larva per plant as a signaling index of H. virescens in chickpea.