Potential of botanical materials as protectants against Sitophilus zeamais Motschulsky (Coleoptera:curculionidae) on stored maize

Doutoramento em Engenharia Agronómica - Instituto Superior de AgronomiaLaboratory studies were carried out in order to evaluate the effects of some formulations from Mentha pulegium L., Lonchocarpus sericeus (Poir.) Kunt, Daphne gnidium L., Laurus nobilis L., Momordica charantia L., Nerium oleander L. and Ptaeroxylon obliquum (Thumb.) Radlk against adult insects of Sitophilus zeamais Motsch. on stored maize. The dusts from leaves of L. nobilis at 30% w/w provided 86% of mortality and reduced F1 progeny emergence up to 68%. At same concentration, dusts of pink flowers from N. oleander and leaves from L. sericeus reduced the F1 progeny up to 57% and 70%, reduced the developmental index and prolonged the developmental period by four and six days, respectively. The suspensions (2,0% v/v) from M. charantia, N. oleander and P. obliquum reduced the F1 progeny emergence up to 58%, 91% and 94% and the number of holes in grains by 75%, 91% and 97%, respectively. The methanol extracts were more effective than n-hexane extracts and affected the F1 progeny emergence and the developmental index. The essential oils of L. nobilis at 1,592μl/cm2 and 3,185μl/cm2 revealed 96% and 100% mortality, respectively. M. pulegium provided of 100% mortality at 0,159μl/cm2 and inhibited completely de F1 progenies. The oils of M. pulegium diluted in methanol at the 1:10 v/v provided 100% mortality (LC50 = 0,014μl) and at 1:100v/v reduced de F1 emergence and the developmental index. The diluted oils of L. nobilis in methanol and n-hexane did not affect any of the parameters studied