Biologia e tabela de vida de fertilidade de Helicoverpa armigera (Lepidoptera: Noctuidae) criada em diferentes hospedeiros

Abstract

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a polyphagous species that has caused damage to several crops, such as cotton, soybean, wheat, beans, tomatoes, corn and weeds in several Brazilian states. So that there is an effective control of H. armigera in production systems, based on the Integrated Pest Management (IPM), conducting bio-ecological studies of this pest is required. The objective of this work was to study the biology and the parameters Helicoverpa armigera fertility life table when their larvae were fed on cotton plants, corn, soybeans, wheat and artificial diet. Cotton seed, soybean, corn and wheat were sown at home-a greenhouse at Embrapa Agropecuária Oeste (Dourados-MS) for the production of vegetative and reproductive structures that were offered as food the H. armigera caterpillars. Leaves and reproductive soybean structures, wheat, cotton, corn, as well as artificial diet were provided from the first instar of the pest and kept under controlled environmental conditions (temperature: 25 ± 1 ° C, RH: 70 ± 10%, photoperiod: 14 h). Larvae were individually placed in plastic petri dishes (60 x 15 mm) and kept at this setting until pupation container and subsequent adult emergence. The width and length of larvae and pupae were measured using a digital caliper. The experimental design was completely randomized, with 170 individual / treatment caterpillars, with each replicate consisting of 10 tracks, totaling 17 repetitions for each treatment (host plants and artificial diet). Adults were kept individually in cages consist of PVC pipes covered with tulle 100 mm tissue type in which the moths performed postures. We used a couple per cage (repeat), totaling 20 repetitions / treatment. Were recorded daily number of eggs / female and mortality of males and females from the different treatments. Biology and the parameters of H. armigera life table when fed on different host plants and artificial diet were subjected to analysis of variance (ANOVA) and when found significant effect of treatment, the means were compared by Tukey test at 5% probability. The total cycle of H. armigera was higher for insects fed wheat (52.7 days) and soybeans (52.2 days). The average weight of female pupae was not influenced by different hosts used as food. Regarding the pace of posture, the insects fed on soybeans and cotton, had a more uniform oviposition pattern in reproductive period than those fed with artificial diet, wheat and corn. For emergency rate of H. armigera adults, it was found that most insects emerged to eleven days, the protandry phenomenon is not observed. Cotton hosts, soy and artificial diet have higher variability of the stages of development, adult female survival rate in the reproductive period and fecundity compared to other hosts, showing, these to be most suitable food for the development of populations of H. armigera.