EFeito dos extratos aquosos de Alibertia sessilis e Alibertia intermedia (Rubiaceae) sobre a preferência alimentar de Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae

Abstract

Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) is one of the main pests responsible for causing damage to Brassica crops. Chemical methods are still the most commonly used management alternative for this pest. This insect has developed resistance to over 101 cataloged products. The high level of resistance of this insect is due to its adaptive capacity and genetic elasticity. In order to reduce the damage caused by chemical insecticides, botanical extracts have emerged as an alternative for less environmentally aggressive control methods. Thus, the aim of this study was to evaluate the effect of aqueous extracts of Alibertia intermedia (Mart.) (Rubiaceae) and Alibertia sessilis (Vell.) K. Schum (Rubiaceae) on the feeding preference of P. xylostella with a choice. Both extracts were prepared at concentrations of 10%. Two cabbage discs were immersed for 40 minutes and then placed in an equidistant cross shape. After this, the discs were placed in Petri dishes containing filter paper, and one P. xylostella larva was placed in the center of each dish, then covered with plastic wrap and perforated for O2 passage. After 48 hours, the discs were scanned to evaluate the consumption area using ImageJ software. The results showed a feeding deterrent effect on P. xylostella feeding. The leaf area consumed in the A. sessilis extract was approximately three times greater in the control discs than in the extract-treated discs. In the A. intermedia extract, it was approximately nine times greater in the control discs when compared to the extract-treated discs. Therefore, botanical extracts are effective for pest control, providing a less aggressive alternative for the environment, reducing the environmental impacts caused by synthetic insecticides, and ensuring ecosystem preservation.