Vásquez-Castro Javier A, De Baptista Gilberto C, Trevizan Luiz R P, Gadanha Casimiro D
Department de Entomología, University Nacional Agraria La Molina, Lima, Peru.
Neotrop Entomol. 2009 May-Jun;38(3):405-9. doi: 10.1590/s1519-566x2009000300017.
Insect-pest mobility can influence insect susceptibility to the insecticides used to control them. The objective of this work was to evaluate the flight activity of Sitophilus oryzae (L) and Sitophilus zeamais Motsch populations reared on corn and wheat grains, and its relationship with insecticide susceptibility. Unsexed adult insects with ages between 10 and 20 days were placed on a plastic tray. A 40-watt incandescent light bulb was positioned at a 50 cm height relative to the tray. Flight activity was evaluated during 30 min. In the LC50 estimation bioassays, the insects were exposed to dry residues of the organophosphorus insecticide fenitrothion and of the pyrethroid insecticide esfenvalerate on the internal surface of glass vials. Mortality was evaluated 24 h after installation of the experiments. Sitophilus zeamais showed greater flight activity when compared with S.oryzae; likewise, insects reared on corn had greater flight activity than those reared on wheat. Sitophilus oryzae was less susceptible to the insecticides studied than S. zeamais. Adults reared on wheat were more susceptible to the insecticides than those reared on corn. This study demonstrates that the lower flight activity of S. oryzae is related to its greater tolerance to insecticides.
害虫的移动性会影响其对用于防治它们的杀虫剂的敏感性。本研究的目的是评估在玉米和小麦籽粒上饲养的米象和玉米象种群的飞行活动，以及其与杀虫剂敏感性的关系。将10至20日龄的未分性别的成虫放置在一个塑料托盘上。在托盘上方50厘米处放置一个40瓦的白炽灯泡。在30分钟内评估飞行活动。在半数致死浓度（LC50）估计生物测定中，将昆虫暴露于玻璃小瓶内表面上的有机磷杀虫剂杀螟硫磷和拟除虫菊酯杀虫剂乙氰菊酯的干燥残留物中。在实验设置24小时后评估死亡率。与米象相比，玉米象表现出更高的飞行活动；同样，在玉米上饲养的昆虫比在小麦上饲养的昆虫具有更高的飞行活动。米象对所研究的杀虫剂的敏感性低于玉米象。在小麦上饲养的成虫比在玉米上饲养的成虫对杀虫剂更敏感。本研究表明，米象较低的飞行活动与其对杀虫剂的更高耐受性有关。
