The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is the main pest of sorghum, Sorghum bicolor L. Moench (Poaceae), in Mexico. To control this insect, farmers currently use synthetic chemical insecticides, which are toxic to humans and biodiversity. However, natural products are a promising potential source of safer alternative means to control different agricultural pests. The main objective of this study was to evaluate the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic and linoleic acids), the phytosterol ß -sitosterol, and the flavonoid rutin. The results showed that fatty acids were the most effective against M. sacchari ; the highest mortality rate (85%) was produced by linoleic acid and the LC 50 was 1,181 ppm, followed by stearic and palmitic acids with mortality percentages of 74 and 63%, respectively, at a concentration of 2,500 ppm at 72 h. The positive control, imidacloprid, had 100% mortality in 24 h and the tween 20 negative control exhibited 4% mortality in 72 h. Our results show that commercial fatty acids are effective against adults of M. sacchari , and can be considered an environmentally friendly alternative to the frequent use of synthetic chemical insecticides.

This study investigates updated information in different search engines on the distribution, phytochemistry, pharmacology, and toxicology of Brugmansia suaveolens (Solanaceae) using the extracts or chemical compounds at present. This plant has been used in traditional medicine in different cultures as a hallucinatory, analgesic, aphrodisiac, nematicide, sleep inducer, and muscle relaxant, as well as a treatment for rheumatism, asthma, and inflammation. The flowers, fruits, stems, and roots of the plant are used, and different chemical compounds have been identified, such as alkaloids, volatile compounds (mainly terpenes), coumarins, flavonoids, steroids, and hydrocarbons. The concentration of the different compounds varies according to the biotic and abiotic factors to which the plant is exposed. The toxic effect of the plant is mainly attributed to atropine and scopolamine, their averages in the flowers are 0.79 ± 0.03 and 0.72 ± 0.05 mg/g of dry plant, respectively. Pharmacological studies have shown that an aqueous extract exhibits the antinociceptive effect, at doses of 100 and 300 mg/kg i.p. in mice. On the other hand, the ethanolic extract at 1000 mg/L, showed a nematocidal activity in vitro of 64% against Meloidogyne incognita in 72 h. Likewise, it showed a 100% larvicidal activity at 12.5 mg/L against Ancylostoma spp. In another study, the lethal activity of shrimp in brine from an ethanolic extract showed an LC₅₀ of 106 µg/mL at double serial concentrations of 1000–0 (µg/mL). Although there are pharmacological and phytochemical studies in the plant, they are still scarce, which has potential for the examination of the biological activity of the more than one hundred compounds that have been reported, many of which have not been evaluated.

The insecticidal activity of the hexane extract and fractions of Ricinus communis leaves against the yellow sugarcane aphid ( Sipha flava ) was evaluated in adults using contact bioassays by fumigation. The n -hexane extract at a concentration of 10,000 ppm achieved the highest mortality rate (80%), the positive control exhibited 100% mortality and the negative control only presented 4% mortality over the 72-hour experimental time. By means a chemical fractionation of the hexanic extract of R. communis leaves, it was possible to obtain an F4 fraction with an aphid mortality of 92% at 10,000 ppm in 72 hours. F4 GC-MS identified linoleic acid as the major compound (84.5%). The extract of R. communis and linoleic acid could be considered for integrated pest control as a more ecologically friendly alternative to synthetic chemical insecticides.

The main objective of the study was to identify chemical compounds of extract of acetone of shell + almond (EACA) and nut of almond (EAA) of Jatrofa curcas and evaluate bioactivity against Copitarsia decolora in laboratory and greenhouse conditions. In ingestion experiments, extracts at 250, 500, 1,000, 1,500, and 2,000 ppm were mixed into artificial diet. Checks were artificial diet mixed with a botanical insecticide Margosom® 0.3% EC (active ingredient [AI] 250 ppm, azadirachtin), and diet plus only water. EAA at 250 and 1,000 ppm inhibited larval weight and prolonged larval development of C. decolora. EAA at 500 ppm and EACA at 1,500 ppm caused most deformation in pupae and adults. As many as 50% of C. decolora larvae occurred with EAA at 500-. EAA was the most active extract in laboratory tests and later evaluated at 250, 500, and 1,000 ppm applied to cabbage plants infested with C. decolora larvae in a greenhouse. Two checks were cabbage (Brassica oleracea var. capitata) plants without extract (water only) and pyrethroid insecticide (Alfadex® AI 21.29% cypermethrin) at 500 ppm. Gas chromatography-mass spectrometry (GC-MS) analysis of the acetonic extract of Jatropha curcas seed identified oleic acid as the major compound. EAA at 1,000 ppm and Alfadex were most effective at protecting cabbage plants from attack by larval C. decolora.

En esta investigación evaluamos la actividad insecticida de una fracción acuosa de tallos de Serjania schiedeana Schltdl. (Sapindaceae) (FASs), a concentraciones de 250, 500, 1,000, 1,500, y 2,000 ppm, en laboratorio e invernadero en plantas de maíz sobre larvas neonatas de Spodoptera frugiperda Smith (Lepidoptera: Noctuidae). Los resultados de los bioensayos de laboratorio mostraron que a los 14 días el FASs a 250 y 1,500 ppm inhibió 50 y 20% el peso larval del insecto. La FASs en todas sus concentraciones ocasionó una mortalidad larval superior a 50% y una mortalidad total de larvas + pupas del 100%, excepto a 500 ppm. En el invernadero, a partir del día siete las plantas de maíz asperjadas con FASs a 250 y 2,000 ppm disminuyeron el daño de las larvas en más del 18%. Un perfil fitoquímico de la FASs, resultó positivo para alcaloides, flavonoides y taninos, estos compuestos podrían tener relación con el efecto insecticida contra S. frugiperda. Los resultados demuestran que la FASs puede ser considerada para el desarrollo de nuevos insecticidas botánicos y posiblemente ser considerados en el control integrado de plagas.

Aphids (Hemiptera: Aphididae) are cosmopolitan generalist pests of many agricultural crops. Their ability to reproduce rapidly through parthenogenesis allows them to quickly reach population sizes that are difficult to control. Their damage potential is further exacerbated when they act as vectors for plant pathogens, causing diseases in plants. Aphids are typically managed through the widespread use of insecticides, increasing the likelihood of short-term insecticide resistance. However, for the past few decades, entomopathogenic bacteria have been used as an alternative management strategy. Entomopathogenic bacteria have demonstrated their effectiveness for biologically suppressing insect pests, including aphids. In addition to identifying bacterial species that are pathogenic to aphids, research has been conducted on toxins such as Cry, Cyt, Vip, recombinant proteins, and other secondary metabolites with insecticidal activity. Most studies on aphids have been conducted in vitro, exposing them to an artificial diet contaminated with entomopathogenic bacteria or bacterial metabolites for periods ranging from 24 to 96 h. The discovery of new bacterial species with insecticidal potential, as well as the possibility of biotechnological applications through the genetic improvement of crops, will provide more alternatives for managing these agricultural pests in the future. This will also help address challenges related to field application.