Insecticidal Potential of Pure Commercial Molecules against the Sugarcane Aphid, Melanaphis sacchari (Zehntner)1

Sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), is now the main pest of sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Mexico. Several ecologically friendlier alternatives were studied to control the pest, including use of pure commercial molecules. The main objective of the study was to evaluate insecticidal potential of four pure molecules (squalene, xylitol, myristic acid, and quercetin) by fumigation in vitro against apterous M. sacchari adults. Results showed that myristic acid had the strongest insecticidal effect (79%) against M. sacchari, followed by squalene at 2,500 ppm with 56% during 72 hours. Xylitol and quercetin had weaker insecticidal effects. Positive check imidacloprid killed 100% within 24 hours, and the negative check, Tween 20, killed only 4% during 72 hours. Results showed commercial myristic acid and squalene were effective against M. sacchari and could be an environmentally friendly alternative to frequent use of synthetic insecticides.