Resistance Monitoring And Mechanism Of Tobacco Aphids To Insecticides

Myzus persicae (Sulzer) , (Hemiptera: Aphididae), the peach-potato aphid, is an important pest of a number of agriculturally important crops, causing damage through feeding and virus transmission. Control is achieved primarily by the application of insecticides, often with multiple applications each year. This has led to the evolution of insecticide resistance conferred by three genetically independent mechanism (Devonshire et al, 1998). Tobacco aphid is one of important pest in tobacco-producing in Yunnan. Due to extensive and repeated use of insecticides, this species has developed insecticide -resistance to most insecticides, rendering all but a very few insecticides ineffective, which waste time and money and result in environmental problems. At least three different resistance mechanisms, known as esterase, MACE (Modified Acetylcholinesterase) and kdr (knockdown resistance) have been found in Myzus persicae. The first of those to be characterized was over-production of one of two closely related carboxylesterases (E4 and FE4) , Two types of target-site insensitivity conferring insecticide resistance have also been found in Myzus persicae. Individuals with modified acetylcholinesterase (MACE) show high levels of resistance to dimethyl carbamates such as pirimicarb and triazamate (Moores et al, 1994). The MACE phenotype has recently been shown to be associated with a single amino acid substitution (serine to phenylalanine, S431F) within the active site of the enzyme (Andrews et al, 2002; Nabeshirma et al, 2003).In this paper, the status quo, mechanism and development of resistance of tobacco aphid are studied, and the results are shown as follows.The aphids from Tongwei town, Weixi county, Diqing canton, was screened as susceptible strain, through monitoring the resistance level of tobacco aphids in these places where tobacco is planted for a short-term or non-tobacco-producing area, susceptible strain aphid are sensitive to endosulfan, methomyl, methamidophos, chlorphoxim, omethoate, deltamethrin, λ-cyholothrin. The diagnostic dose of these insecticides to tobacco aphid are respectively 5638.4 mg/kg, 1248.3 mg/kg, 579.7 mg/kg, 989.3 mg/kg, 1005.6 mg/kg, 19.3 mg/kg and 5.3 mg/kg.Detecting insecticides-resistance of tobacco aphids in 9 tobacco-planting areas in...