Effect Toxic and Behavioral of Annona mucosa (Annonaceae) on the Tomato Leaf Miner

Abstract

Tuta absoluta (Meyrick) is considered a pest with high destructive potencial and its control depends mainly on successive applications of insecticides. Therefore, new alternatives for the control of the tomato leaf miner using plants with insecticidal potential have been examined. This study was aimed at evaluating the toxic effect of Annona mucosa extract on the developmental stages of T. absoluta. Larval survival bioassay was performed in which newly-hatched caterpillars were inoculated in tomato leaflets sprayed with A. mucosa extract in the LC50 and LC90 treatments and the insecticidal controls chlorfenapyr, methanol, and water. To identify the mode of action of the extract in caterpillars, histological analyzes of the integument and gut were carried out. To evaluate ovicidal activity and oviposition repellency, only the LC50 treatment and controls (water and methanol) were carried out. In the ovicidal bioassay 75 eggs/treatment were used, and for the oviposition repellency, 10 couples/treatment, with 10 replicates. In the larval survival bioassay, a significant difference among survival curves, and the crude extract of A. mucosa significantly reduced the survival of T. absoluta caterpillars. The mode of action of the extract occurred by contact and ingestion, as indicated by changes in the integument and gut. The extract of A. mucosa also interfered in the embryonic development of T. absoluta, with a viability of more than 90% of the eggs. Regarding the behavioral effect, the extract reduced oviposition rates of T. absoluta females. Thus, A. mucosa extract had toxic effects on the different stages of pest development.

Chitin Biosynthesis Inhibitors in Euschistus heros Fabr. (Hemiptera: Pentatomidae): Morphometric Alterations in Testes and Nuclei of Testicular Accessory Cells of Adults

“…Five testicles of each treatment fixed in Karnovsky's solution were dehydrated in a gradual sequence of ethyl alcohol and included and embedded in Leica HistoResin® (Leica) using protocol of Insect's Laboratory/Department of Histology/UEL. The cross sections (5 µm) were obtained and stained by HE, adapted of Bastos et al (2018). The sections were analyzed and photographed in the Axiophot® photomicroscope (Zeiss) coupled with a camera Moticam® 3.0 MP (Motic).…”