Imidacloprid resistance

Recently, resistance to imidacloprid became a serious problem for crop protection. Comparative studies of other neonicotinoids revealed a high crossresistance to acetamiprid and thiamethoxam against imidacloprid-resistant strains [22]. However, bioassays exhibited that 4a has good activity against imidacloprid-resistant strains of brown planthopper (Table IV), showing very low cross-resistance to imidacloprid, as shown in Table V. 

Table IV. Bioassays of IPP against sensitive and imidacloprid-resistant strains ofbrown planthopper (Nilaparvata lugens).

Table V. Cross-resistance of imidacloprid-resistant strains on 4a.

Karunker I, Morou E, Nikou D, Nauen R, Sert-chook R, Stevenson BJ, Paine MJ, Morin S, Von-tas J (2009) Structural model and functional characterization of the Bemisia tabaci CYP6CMlvQ, a cytochrome P450 associated with high levels of imidacloprid resistance. Insect Biochem Mol Biol 39 697-706... 

Roditakis E, Morou E, Tsagkarakou A, Riga M, Nauen R, Paine M, Morin S, Vontas J (2011) Assessment of the Bemisia tabaci CYP6CMlvQ transcript and protein levels in laboratory and field-derived imidacloprid-resistant insects and crossmetabolism potential of the recombinant enzyme. Insect Sci 18 23-29... 

In a recent study, resistance to the neonicotinoid insecticide, imidacloprid, in the brown plant hopper, Nilaparvata lugens, was found to be due to a point mutation at a conserved position in two nAChR subunits. As a result, it reduced the receptor binding of imidacloprid (Liu et al., 2005). 

Liu, Z., Williamson, M.S., Lansdell, S.J., Denholm, I., Han, Z., and Millar, N.S. A nicotinic acetylcholine receptor mutation conferring target site resistance to imidacloprid in Nilaparvata lugens (brown planthopper), Proc. Natl. Acad. Sci. USA, 102, 8420, 2005. 

The extinction process, when the CS is delivered alone, can also be used to indicate potential effects of toxic compounds. The acquisition phase shows the ability of treated animals to learn the temporal relation between the US and the CS, whereas the extinction phase indicates their resistance to extinguish the response to a CS no longer associated with a reward. Ingestion of dicofol [34], endosulfan [35, 46], imidacloprid, and hydroxy-imidacloprid [48] significantly reduced the level of conditioned responses in both acquisition and extinction phases. By contrast, the response level was not reduced in bees conditioned prior to an exposure to permethrin... 

Fig. 28.4.3. Efficacy of spiromesifen 8a against whitefly strains resistant to (a) imidacloprid and (b) pyriproxyfen (Taken from Guthrie et al., 2003.)...

The EU ban on neonicotinoids from December 2013 means that seed dressings containing clothianadin, imidacloprid and thiomethoxam can no longer be used for the control of cabbage stem hea beetle (CSFB) or the peach-potato aphid, a vector of turnip yellows virus. Fohar apphed pyrethroids ate now the only control for CSFB, but resistance is now widespread. 

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