Leafminer resistance

Castor is a very hardy plant and in some areas an invasive weed. It is susceptible to numerous insect and microbial pests, but castor germplasm is available for resistance to many of these pests. One key to successful breeding is the ability to screen large numbers of plants quickly. In the case of leafminer resistance, Anjani et al. (2010) found that resistance was correlated with high phenolic content as reflected by purple leaf coloration. Over 100 castor plant accessions, of 1979 tested, proved to be resistant to Fusarium (Fusarium oxysporum f. Sp. ricini) wilt based on their limited susceptibility to wilting in a contaminated field (Anjani et al., 2014). 

Leafminers. A relatively recent case of resistance with serious implications for the floricultural and vegetable crops industries concerns the leafminer, Liriomyza trifolii. Over the past ten years there has been a dramatic rise in the importance of Liriomyza species as major pests of numerous ornamental and agricultural crops (29) and a world-wide extension of the geographic distribution of some of these insects, mainly through infested plant material. 

To summarize the resistance situation in broad terms, no key pest such as the codling moth, apple maggot, plum curculio has developed resistance to the OP azinphosmethyl, whereas a variety of secondary pests such as mites, aphid, leafhoppers, leafminers and their natural enemies have developed resistant strains thus azinphosmethyl has become more selective. The example cited later of management of cyhexatin resistance management in the spider mite... 

Anjani, K., Pallavi, M., Sudhakara Babu, S.N., 2010. Biochemical basis of resistance to leafminer in castor (Ricinus communis L.). Ind. Crops Prod. 31,192-196. 

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