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Castor bean (Ricinus communis) seeds contain ricinine, an alkaloid with insecticidal and insectistatic activities. Elicitation with salicylic acid (SA) has proven to stress R. communis and might modify the ricinine concentration. The aim of this study was to evaluate the concentration of ricinine in the bagasse of seeds from R. communis elicited with exogenous SA under greenhouse conditions. Plants were grown and divided into five groups, which were sprayed with SA and drench with 50 mL 60 days after sowing with concentrations of SA (0, 100, 300, 600 and 900 µM). Clusters were mixed and separated according to the treatment, and dried. The seeds were ground, the oil was extracted by Soxhlet with hexane, and then the bagasse was extracted with methanol. Ricinine was determined by HPLC. Elicitation did not change the plant height or diameter, the control group had 9.17 µg mL−1 of ricinine, and the concentrations followed a hormesis curve with the peak at 300 µM of SA that had a ricinine concentration of 18.25 µg mL−1. Elicitation with SA might be a cost-effective technique to increase ricinine from R. communis bagasse.

Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), infests more than 80 crop species and is the principal pest of maize (Zea mays L. (Poaceae) in Mexico. Although insecticides are used to control the pest, they can cause environmental damage and negatively affect human health. Essential oils are an alternate for managing the insect. The aim of this study was to investigate insecticidal and insectistatic activities of essential oil of salvia (Salvia keerlii Benth, Lamiaceae) against larval and pupal S. frugiperda. The oil at 400, 600, and 1,000 mg liter-1 killed 65, 55, and 85% of larvae, respectively, with estimated LC50 of 590.2 mg liter-1, but did not adversely affect pupae. Insectistatic activity at concentrations of 600 and 1,000 mg liter-1 delayed larval development as many as 13.8 days (compared to a negative check). The main compounds of essential oil of S. keerlii were identified by GC-MS as 2-pentanone,4-hydroxy-4-methyl, caryophyllene oxide, and 1,8-cineole. The 1,8-cineole at concentrations of 600 and 1,000 mg liter-1 killed all S. frugiperda larvae, with an estimated LC50 of 249.4 mg liter-1.

Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) (fall armyworm) is a pest native to the Americas that affects a variety of crops. Its control is based on chemical insecticides. However, this practice has been associated with changes in the susceptibility of pests to various insecticides. The use of plant products represents an eco-friendly alternative. The objective of this work was to evaluate the larvicidal activity of the chloroform extract of Senna crotalarioides (Kunth) H.S. Irwin & Barneby (Fabaceae) to control S. frugiperda. The chloroform extract of S. crotalarioides caused significant larval mortality, and reduced pupal weight and adult emergence. The analysis by gas chromatography coupled with mass spectrometry (GC-MS) revealed the presence of 22 compounds in the chloroform extract of S. crotalarioides leaves, with the straight-chain aliphatic fatty alcohol 1-octacosanol as the main component. This study revealed that the leaves of S. crotalarioides synthesize long chain alcohols, which increased the mortality of S. frugiperda in its larval stage, including the pupal stage. The extract also caused a decrease in the S. frugiperda pupal weight. The potential use of the chloroform extract obtained from S. crotalarioides and its principal chemical constituent is proposed as a promising alternative to control S. frugiperda.