Resíduos de frutos de pequizeiro no controle de Spodoptera frugiperda e Agrotis ípsilon

Abstract

This work was carried out to study the possibility of using the residue of the pequi fruit to control Spodoptera frugiperda and Agrotisipsilon. Pequi fruits peel were used in the preparation of a compound which was prepared from the mixture with sugarcane straw and cattle manure. The compound was evaluated on the S. frugiperda and A. ipsilon pre-pupae and pupae 24 hours old in the proportion of 5 g /L, 10g/L, 20g/L, 30g/L, 100% and one control. Assays were set in randomized block design with six treatments and 50 replications. The pupal duration and mortality, pupal and adult deformation were evaluated. The Pequi fruit peels was evaluated as for the development of A. ipsilon and S. frugiperda using aqueous extracts. Concentrations of 0.3% to 2.5% of the aqueous extract from the addition of different proportions of Pequi peels powder were prepared. These concentrations were added to artificial diet of caterpillars to replace water from your preparation. Assays were performed in RBD with six and five treatments for A. ipsilon and S. frugiperda, respectively, plus the controls. Each treatment had 50 repetitions. We evaluated mortality and larval and pupal duration, male and female pupae weight and pupae and adults deformation. Aqueous extracts of Pequi were also evaluated on the field in order to control the infestation of S. frugiperda larvae in corn. The extracts were pulverized in maize plants at the concentrations of 0.8%, 2.5%, 5.0% and 10.0%. The experimental design was in randomized blocks, everyone represented by five treatments and five repetitions. The sprayed maize plants had their leaves collected 24 hours after the first application of the extract, to be evaluated in the laboratory on the S. frugiperda development. The leaves were cut, placed in glass tubes, where a newly hatched S. frugiperda caterpillar was placed. We evaluated the duration and larval and pupal mortality, male and female pupae weight, pupae and adults deformation. Assays were carried out in randomized block design, with four treatments plus the control each treatment had 50 replications. The compound of pequi when in contact with S. frugiperda and A. ipsilon pre-pupae and pupae caused lengthening of the pupal stage, increased pupae mortality and pupae and adults deformation. Intake of diets containing pequi extract concentrations from 0.8% to 2.5% caused total mortality of S. frugiperda caterpillars. For A. ipsilon, intake of artificial diet containing pequi extract caused high larval mortality, lengthening the duration of larval and pupal phase, pupal mortality, reduced pupal weight and adult deformation. The extract sprayed on the maize plants reduced the infestation of S. frugiperda caterpillar. Intake of corn leaves pulverized with the aqueous extract by the S. frugiperda caterpillars lengthened the duration of the larval and pupal stages. All evaluated pequi extract concentrations caused higher larval mortality than control.