Pyrethroid resistance

Interestingly, it appears that earlier selective pressure by dichlorodiphenyl trichloroethene (DDT) raised the frequency of kdr genes in the population before pyrethroids came to be used. Thus, some pyrethroid resistance already existed before these insecticides were applied in the field. 

The other major mechanism of pyrethroid resistance found in some field strains of Heliothis virescens was enhanced detoxication due to a high rate of oxidative detoxication, mediated by a form of cytochrome P450 (McCaffery 1998). Some strains, such as PEG 87, which was subjected to a high level of field and laboratory selection, possessed both mechanisms. Other example of pyrethroid resistance due to enhanced detoxication may be found in the literature on pesticides. 

Golenda, C.F. and A.J. Forgash. 1989. The distribution and metabolism of fenvalerate in pyrethroid-resistant and susceptible house flies. Pestic. Biochem. Physiol. 33 37-48. 

The issue of pyrethroid resistance in houseflies and mosquitoes and the countermeasures are described below. 

By topical application, Katsuda et al. determined LD50 values of natural pyrethrins and several pyrethroids against the pyrethroid-susceptible CSMA strain and the pyrethroid-resistant Hiroyama strain of M. domestica. The resistant strain was originally collected in 1996 from a hog farm in Hiroyama, Niigata Prefecture. Their resistance ratios, R/S, are shown in Table 3. 

Table 3 Pyrethroid resistance against Musca domestica (tested in 1997)...

Until recently, the resistance of mosquitoes to pyrethroids has not been taken as a serious issue. In Japan, C. p. pallens and Aedes albopictus (Skuse) are the main species living around houses. Although mosquito coils have utilized natural pyrethrins as insecticidal ingredients for about 50 years and then allethrin for about 50 years, there has been no report on resistance development. The reason for this is considered to be the short active time of 4-5 months per year for C. p. pallens. Yasutomi et al. [50] reported in 1989 the presence of pyrethroid-resistant Culex tritaeniorhynchus in Okinawa, but Japanese encephalitis transmitted by C. tritaeniorhynchus decreased markedly after 1992 and disappeared. 

Yasutomi K, Takahashi M (1989) Insecticidal resistance of Culex tritaeniorhynchus in Chinen, Okinawa Prefecture, with special reference to the mechanism of pyrethroid-resistance. Jpn JSanitZool 40 315-321... 

Kasai S, Komagata O, Itokawa K, Kobayashi M, Tomita T (2010) Mechanisms of pyrethroid resistance in adult Aedes aegypti. Med Entomol Zool 61(Suppl) 46... 

Lee SH, Soderlund DM (2001) The V410M mutation associated with pyrethroid resistance in Heliothis virescens reduces the pyrethroid sensitivity of house fly sodium channels expressed in Xenopus oocytes. Insect Biochem Mol Biol 31 19-29... 

Sparks, T.C., Leonard, B.R., and Graves, J.B., Formamidine metabolism and pyrethroid interactions in pyrethroid resistant tobacco budworms, 1989 Proceedings of the Beltwide Cotton Production Research Conference, National Cotton Council of America, 1989, p. 330. 

In resistant populations, the frequency of resistance alleles can be very high. For example, using the real-time PCR amplification of specific allele (rtPASA) method, Kim et al. (2007) showed that the frequency of the pyrethroid resistance allele (Leu-Phe mutation in... 

Sequestration in insects This is another resistance mechanism in which GSTs were found to be involved in pyrethroid resistance. Kostaropoulos et al. (2001) have reported that GST confers protection against deltamethrin by binding to the insecticide in the yellow mealworm ijenebrio monitor). 

Yu and Nguyen (1996) showed that selection of a strain of diamondback moth (Plu-tella xylostella) with permethrin for 21 generations resulted in over 600-fold resistance to permethrin in this strain. The resistant strain was also cross-resistant to all pyrethroids tested, including bifenthrin, fenvalerate, esfenvalerate, A.-cyhalothrin, fluvalinate, and tral-omethrin. However, it remained susceptible to organophosphate, carbamate, cyclodiene, neonicotinoid, avermectin, and microbial insecticides tested. Biochemical studies indicated that pyrethroid resistance observed in this strain was most likely due to decreased target site sensitivity. 

He, H., Chen, A.C., Davey, R.B., Ivie, G.W., and George, J.E., Identification of a point mutation in the para-type sodium channel gene from a pyrethroid resistant cattle tick, Biochem. Biophys. Res. Commun., 261, 558,1999. 

Kim, H.J., Hawthorne, D.J., Peters, T., Dively, G.P., and Clark, J.M., Application of DNA-based geno-typing techniques for the detection of kdr-like pyrethroid resistance in field populations of Colorado potato beetle, Pestic. Biochem. Physiol., 81, 85, 2005. 

Kim, H., Baek, J.H., Lee, W.J., and Lee, S.H., Frequency detection of pyrethroid resistance allele in Anopheles sinensis populations by real-time PCR amplification of specific allele (rtPASA), Pestic. Biochem. Physiol., 87, 54, 2007. 

Plapp, F.W., Jr., Campandhola, C., Bagwell, R.D., and McCutchen, B.F., Management of pyrethroid-resistant tobacco budworms on cotton in the United States, in Pesticide resistance in arthropods, Roush, R.T. and Tabashnik, B.E., Eds., New York Chapman and Hall, 1990, p. 237. 

Vontas, J.G., Small, G.J., and Hemingway, J., Glutathione S-transferases as antioxidant defence agents confer pyrethroid resistance in Nilaparvata lugens, Biochem. /., 357, 65,2001. 

Pyrethroids are widely used to control many agriculturally and medically important insect pests. Due to intensive use of pyrethroids in pest control, many pest populations have developed resistance to these compounds. One major mechanism of pyrethroid resistance, conferred by the knock down resistance gene (Mr), is reduced target site (sodium channel) sensitivity to DDT and pyrethroids. Studies on the molecular basis of Mr and Mr-type resistance in various insects are enhancing our understanding of the structure and function of insect sodium channels and the molecular interaction between insect sodium channels and pyrethroids. In this chapter, I will review recent advances in... 

These include amitraz (110), prepared from 54, a member of the form amidine class, active against mites and ticks, that have replaced organophosphorus compounds. Notably, amitraz is active against newer strains of pyrethroid-resistant ticks. The reaction of diphenylamine (8) with sulfur in the presence of iodine as catalyst yields the anthelmintic (worming agent) phenothiazone (phenothiazine) (111) (Scheme 24). It is too toxic for human use, though it is an intermediate in the production of antipsychotic drugs. 

Forrester, N.W., Bird, I..J. and I dryland, J.K. (1993). Management of pyrethroid and endosulfan resistance in UeiicoveriHi arm gem (Lepidoptera Noctuidne) in Australia. Section 10. Pyrethroid resistance resistance breaking pyrethmids. Bull. Entomoi. Res. (supplement l. September), 132 pp. 

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