Using Azadirachtin to Transform Spodoptera frugiperda from Pest to Natural Enemy

Abstract

Spodoptera frugiperda and Rhopalosiphum maidis, as main pests, seriously harm the safety of maize. At present, chemical pesticides are mainly used to control these pests. However, due to residue and resistance problems, more green, environmentally benign, simple preventive control technology is needed. In this study, we reported the reason for the antifeedant activity of azadirachtin on S. frugiperda and proposed that S. frugiperda treated with azadirachtin would turn from pest into natural enemy. S. frugiperda showed an obvious antifeeding phenomenon to maize leaf treated with various azadirachtin concentrations (0.5~20 mg/L). It was found that maize leaf treated with 1 mg/L of azadirachtin has a stimulating effect on the antenna and sensillum basiconicum of S. frugiperda, and azadirachtin can affect the feeding behavior of S. frugiperda. Additionally, after treating maize leaves or maize leaves + R. maidis with 1 mg/L of azadirachtin, the predatory behavior of S. frugiperda changed from a preference for eating maize leaves to R. maidis. Moreover, the molting of R. maidis can promote the change of this predatory behavior. Our results, for the first time, propose that the combined control technology of azadirachtin insecticide and biological control could turn S. frugiperda from pest into natural enemy, which can effectively eliminate R. maidis and protect maize. This combined control technology provides a new way for pest management and has good ecological, environmental, and economic benefits.

Serotonergic Neurons in the Brain and Gnathal Ganglion of Larval Spodoptera frugiperda

“…The increased serotonin could alter activities in memory, learning, sleep, and locomotor, while the decreased serotonin reduce the peristalsis movements ( Oyarzabal-Armendariz et al, 2021 ). Therefore, the antifeedant and repellent effects of azadirachtin on S. frugiperda might be mediated by serotonin signal ( Lin et al, 2021 ; Oyarzabal-Armendariz et al, 2021 ). Here, we performed immunohistochemistry with antiserotonin serum to examine the distribution of serotonergic neurons in the central nervous system of larval S. frugiperda .…”

Two-way predation between larvae of Spodoptera frugiperda and Spodoptera litura

“…Furthermore, it is found that after S. frugiperda larvae reached 3rd instar, they exhibited aggressive behavior and equally preyed on their natural insect syrphid larvae with a Holling type III response . More interesting, S. frugiperda larvae can stop feeding on maize and prey on Rhopalosiphum maidis by applying a small amount of azadirachtin (Lin et al, 2021). These research results showed S. frugiperda larvae have a clearer competitive advantage over other insects and could compete with a variety of native insects.…”

The Effect of Botanical Pesticides Azadirachtin, Celangulin, and Veratramine Exposure on an Invertebrate Species Solenopsis invicta (Hymenoptera: Formicidae)

“…Botanical pesticides have emerged as prominent alternatives to conventional synthetic chemical pesticides, offering several advantages [ 1 , 7 , 8 , 9 ]. These alternatives are cost effectiveness, biodegradability, possessing multiple modes of action, being readily accessible, and exhibiting low toxicity toward nontarget organisms [ 3 , 10 , 11 , 12 ]. Essential oils derived from plants and similar products typically demonstrate acute toxicity levels exceeding 2 g/kg via ingestion and contact, while exhibiting nontoxicity to mammals, birds, and fish [ 12 ].…”

“…Despite the extensive testing of azadirachtin, celangulin, and veratramine on Lepidoptera, Hemiptera, and Diptera pests [ 11 , 14 , 21 ], their contact toxicity to pest ant species, specifically the red imported fire ant, has not been assessed. Therefore, this study aims to evaluate the contact toxicity, knockdown time, lethal time, and horizontal transmission toxicity of these three natural plant pesticides on RIFA.…”