Effect of the aqueous extracts of the seeds of Talisia esculenta and Sapindus saponaria on fall armyworm

Abstract

The effect of aqueous extracts of Talisia esculenta (T.E.) and Sapindus saponaria (S.S.), were evaluated on the development and mortality of 8-14th day-life Spodoptera frugiperda, an important pest of maize. Corn leaves were dipped in the aqueous extracts (1% w/v) and offered as food to the caterpillars. The treated corn leaves with the extracts caused larval mortality (26.71%/T.E.; 63.3%/S.S.) and also showed effect on the larval weight (237.50 mg/T.E.; 86.65 mg/S.S.) when compared with the control (11.3% and 293.45 mg), mortality and larval weight, respectively. The electrophoresis with gelatin (0.1%) showed two very clear white areas (trypsin activity) in the caterpillars midgut of all the treatments. Only the caterpillar treated with S. saponaria presented significant differences, showing trypsin activity (10.59%). Sapindus saponaria appeared better than Talisia esculenta and showed good potential to be used as control agent for S. frugiperda.Este estudo procurou avaliar o potencial inseticida dos extratos aquosos de sementes de Talisia esculenta (St. Hil.) Radlk (Pitombal) e Sapindus saponaria L. (Saboneteira), ambas da família Sapindaceae, sobre Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), importante praga da lavoura de milho. As folhas de milho foram imersas nos tratamentos com extratos aquosos (1% p/v) e oferecidas como alimento para as lagartas. Os resultados do período larval tais como mortalidade e peso médio foram respectivamente: para S. saponaria 63,15%, 86,65 mg; para T. esculenta 26,71%, 237,50 mg e para o controle 11,3%, 293,45 mg. A eletroforese com gelatina 0,1% mostrou duas regiões brancas muito nítidas (atividade tríptica) no intestino médio das lagartas de todos os tratamentos. Somente as lagartas do tratamento S. saponaria, apresentaram diferenças significativas, com uma atividade tríptica 10,59% menor.

Keywords

• Talisia esculenta
• Sapindus saponaria
• Sapindaceae
• Spodoptera frugiperda
• natural insecticide