Desenvolvimento da Larva-Alfinete em Turfa e Vermiculita

Abstract

The Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) is an important pest for several crops. The purpose of this work was to improve the method of rearing corn rootworm in lab conditions. Four systems were compared for rearing larvae, two with transference and two without transferring the larvae, constituted by maize seedling kept in peat and vermiculite. The following biological parameters were assessed: duration and feasibility in the adult-larva period, pre-oviposition and oviposition periods, males and females longevity, fertility and feasibility, net reproduction rate (Ro), average duration of a generation in weeks (T), innate capacity to increase in number (rm) and increase finite rate (λ) of D. speciosa adults. Based on the results obtained, it could be noticed that there was no influence of the substrates and rearing techniques used in the pre-oviposition and oviposition periods, males and females longevity and also in the whole fertility. However, there was effect on larval feasibility, where a higher feasibility was obtained in the treatment without transferring and with transference when peat and vermiculite were used as substrates, respectively; a bigger duration of the adult-larva period when the insects were reared in vermiculite substrate, regardless the transference; and in the feasibility of the eggs, which was higher in the treatment without transference for the two substrates. The results of the fertility table indicated that the reproduction potential of the D. speciosa significantly increases when the larvae are reared in peat without transference and vermiculite with transference.