Melia azedarach L. Fruit Extract as a potencial candidate in controlling the Neuraeschna Hagen, 1867 (Odonata: Aeshnidae), predominant predators for fish fingerlings

Odonata larvae in fishponds prey on fish fingerlings and decrease the profits from production. With the goal of eliminating these larvae from fishponds, large quantities of pesticides are applied. These products are toxic to fish and have unpredictable effects on the food chain. The objective of this study is to evaluate the effect of the plant extract of fruits of Melia azedarach (CEE) and of methyl parathion (MP) adsorbed in silica in the control of Neuraeschna larvae (Odonata: Aeshnidae). The LC50-18h for CEE was 0.57 mg L-1, and for MP the LC50-12h was 0.17 mg L-1. Two compounds  with the highest concentration were isolated and identified from CEE, linoleic acid and melianone. The latter is a triterpene precursor of limonoids, compounds with insecticide properties. The substitution of synthetic pesticides for natural products is a path towards the sustainability of fish farming

Antifeedant and repellent activities of Melia azedarach L. fruit extracts on fall armyworm

The aim of this study was to evaluate the appetite suppression and insecticidal activity of Melia azedarach aerial component extracts on the larvae of Spodoptera frugiperda obtained from the maceration by solvent, ultrasound and supercritical CO2 extraction. Extracts of aerial components of M. azedarach were obtained by three different extraction methods (maceration, ultrasound and supercritical extraction) using different solvents (ethanol, n-hexane, ethyl acetate and CO2) for use in testing appetite suppression activity in S.  frugiperda (Lepidoptera: Noctuidae). Extracts were sprayed on third instar larvae, which were then placed on corn seedlings. Extracts prepared by ethanol maceration of the fruits and branches showed appetite suppression and repellent activity, extracts of fruits obtained with n-hexane solvent and supercritical CO2  resulted in significantly reduced leaf damage in the corn, with a result equivalent to the positive control (commercial insecticide). Regarding larvae mortality, the supercritical CO2 extract of fruits resulted in the highest S. frugiperda mortality among the tested extracts, equivalent to treatment with positive control. This extract appears to be the most promising for controlling this corn crop insect pest