Distribuição espacial de lysiphlebus testaceipes (cresson) (hymenoptera: aphidiidae) em algodoeiro cultivado em sistema adensado.

Abstract

This research aimed to evaluate the effects of "ultra narrow row cotton”, as an innovative technology, on the population structure of natural enemies. There was difference on the occurrence of: Chrysoperla externa, Cycloneda sanguinea, Scymnus sp., Toxomerus sp. and Orius insidiosus between the spacing adopted. The models were applied to the natural enemy Lysiphlebus testaceipes, because the most abundant. The parameter "b" of the Taylor’s equation was significantly greater than unity in spacing: 0.40 meter and 1.60 meter, whereas on the 0.80 meter, the value "b" was significantly lower than unit (1). Therefore of L. testaceipes in conditions 0.40 and 1.60 m showed agregativity, however the population are uniform on the 0.80 m. Iwao’s model showed that for spacings of 0.80 m and 1.60 m there is a tendency for repulsion of the individuals, because the values of the constant "a" were <1. Good fit of Nachamann’s model was observed only for data population cotton grown in 0.80 m between rows, so for cotton handled in this system, plans aimed at estimating the population level of the parasitoid L. testaceipes can be based only on observations of presence / absence, rather than counting the insects individually. Results of this study are of capital importance for release strategies and especially conservation of L. testaceipes.