Insecticide resistance in the western flower thrips, Frankliniella occidentalis

摘要

The western flower thrips, Frankliniella occidentalis Pergande (Thysanopera: Thripidae) is a serious pest on a wide range of corps throughout the world. F.occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance to insecticides. Pesticide resistance can have a negative impact on integrated pest management programmes with chemical control as one of the components. Resistance to a number of different insecticides has been shown in many populations of F.occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity,and a haplodiploid breeding system. The mechanisms conferring insecticide resistance in insects can be divided into four levels. First, an altered behavirour can aid the insect to avoid coming into contact with the insecticide. Second, a delayed penetration through the integument will reduce the effect of the insecticide at the target site. Third, inside the insect, detoxification enzymes may metabolise and thereby inactivate the insecticide. Fourth,the last level of resistance mechanisms is alterations at the target site for the insecticide Knowledge of resistance mechanisms can give information and tools to be used in management of the resistance problem. Recently, studies have been carried out to investigate the underlying mechanisms conferring resistance in F.occidentalis. It appears that resistance in F.occidentalis is polyfactorial; different mechanisms can confer resistance in different populations and different mechanisms may coexist in the same population. Possible resistance mechanisms in F.occidentalis include: reduced penetration, detoxification by P450-monooxygenases, exterases and glutathione S-transferases, and alterations of acetylcholinesterase, the target site for organophosphate and carbamate insecticides. Target site resistance to pyrethroids (knockdown resistance) may also be a resistance mechanisms in F.occidentalis.