Potenciais efeitos do herbicida glifosato nas características biológicas e reprodutivas de Spodoptera frugiperda e Chrysodeixis includens

Abstract

The herbicide products based on glyphosate are the champions of sales in Brazil, their effectiveness and low cost make them the ideal product for much of the agricultural sector of the country. However, theiruse is still very controversial forthe potential effects they may have on other non-target organisms. Soybean, corn, and cotton crops are the main targetsof these glyphosate products, especially in those regions where genetically modified plants with glyphosate resistance are grown. In addition, these crops have in common that they are often attacked by Spodoptera frugiperda and Chrysodeixis includens, (Lepidoptera: Noctuidae) two pest moths that cause millionaire economic losses in almost everything the world and are a threat to the food security of some regions. Thus, this work aimed to characterize the effect of the herbicide glyphosate on the biology of these two species of insect pests. For this, the study was carried out at the Laboratory of Molecular Entomology and EcoToxicology (M.E.E.T) of the entomology department of UFLA. Toxicology tests were performed on eggs, caterpillars, and pupae for each species using three treatments: 1) commercial product Roundup Original® at the recommended dose in the package insert, 2) the recommended dose diluted 20 times, and 3) only distilled water as a control group. The three solutions were applied directly with micropipettes on the eggs and caterpillars of the two species; pupae were dipped individually in each treatment. After exposure, the larvae and pupae were monitored and their survival and duration of each stage were monitored until the adult emergence. The effect on adults was assessed by evaluating the fertility and fecundity of couples and groups of couples in specialized cages until death. All experiments were carried out under controlled conditions of temperature (25±2°C), relative humidity (70±10%) and photoperiod (12:12 L: D). Our results showed significant negative effects of the use of glyphosate on the survival and reproduction of non-target pest organisms associated with crops of economic importance in Brazil.