Diet and life cycle of the fall armyworm Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in maize treated with the homeopathic preparation Silicea terra

Abstract

The objective of the present study was to assess the diet and life cycle of Spodoptera frugiperda fed with maize plants treated with the homeopathic preparation Silicea terra applied through different methods. We applied the dynamizations 12, 36, 60, and 84 CH were applied to the corn plants by the methods through of spraying (a), irrigation (b), and seed treatment (c). We kept individual third-instar caterpillars in test tubes under controlled laboratory conditions and fed them daily with leaf sections of maize plants that reached stage V6. We assessed consumption and use of food by caterpillars, formation and sex ratio of pupae and adults, fertility, fecundity, adult lifespan, and food preferences in a free-choice test. We observed that S. frugiperda fed with leaf sections of maize, which were sprayed or irrigated with Silicea 36 CH, showed lower consumption and lower use of the food, as well as a larger number of deformed pupae and adults, and shorter oviposition and post-reproductive periods, smaller number of egg mass, eggs per oviposition, and eggs per female. The results show that the caterpillar S. frugiperda has difficulty to feed on maize plants sprayed or irrigated with the homeopathic preparation Silicea 36CH, but when it does, the preparation affects its fertility and fecundity.