Sitophilus oryzae and Sitophilus zeamais are among the main pests of stored grains worldwide, they are very similar species and have great destructive potential, causing numerous damages to grain production. The control of these insects occurs, in general, through chemical insecticides such as the agrochemicals pirimiphos-methyl, an organophosphate, and bifenthrin, a pyrethroid, which are widely used to prevent infestation. Four strains of these two species were exposed to the two classes of agrochemicals mentioned. The polyacrylamide gel electrophoresis technique was used to identify the esterase patterns of the species and eight esterases were identified for S. zeamais, of which four cholinesterases, two carboxylesterases, one acetylesterase, and one arylesterase; and seven esterases for S. oryzae, being four cholinesterases, two carboxylesterases, and one acetylesterase. After exposure to agrochemicals, through dose-response bioassays, the LC₅₀ was determined for each strain, with the SoB strain of S. oryzae being the most resistant to bifenthrin, the SzB strain of S. zeamais being the most resistant to pirimiphos-methyl and the SoA strain of S. oryzae was the most sensitive to both compounds. Analysis of the esterase patterns of insects exposed to these agrochemicals revealed the inhibition and probable involvement of carboxylesterases and cholinesterases in the detoxification processes of organophosphates and pyrethroids.

米象虫和玉米象虫是世界范围内储粮的主要害虫之一，它们的种类非常相似，具有很大的破坏潜力，给粮食生产造成了巨大的损失。通常通过化学杀虫剂来控制这些昆虫，例如农用化学品甲基嘧啶磷（一种有机磷酸酯）和联苯菊酯（一种拟除虫菊酯），广泛用于预防侵染。这两个物种的四个品系暴露于上述两类农用化学品。采用聚丙烯酰胺凝胶电泳技术对玉米淀粉酶进行了鉴定，鉴定出8种酯酶，其中胆碱酯酶4种，羧酸酯酶2种，乙酰酯酶1种，芳基酯酶1种；米酵母有七种酯酶，即四种胆碱酯酶、两种羧酸酯酶和一种乙酰酯酶。暴露于农用化学品后，通过剂量反应生物测定，确定了每个菌株的LC _{50 ，其中}米链霉SoB 菌株对联苯菊酯最具耐药性，玉米链霉SzB 菌株对甲基嘧啶磷耐药性最强米霉SoA 菌株对这两种化合物最敏感。对接触这些农用化学品的昆虫的酯酶模式的分析揭示了羧酸酯酶和胆碱酯酶在有机磷酸酯和拟除虫菊酯的解毒过程中的抑制和可能的参与。