Host plant resistance to insect pests of cruciferous crops with special reference to flea beetles feeding on canola - a review

摘要

Several insect pests of cruciferous vegetable and oilseed crops are economically important. Chemical control has been the most common method of control of these pests. Although this method of control has been effective against many insects, it has serious drawbacks and a continued reliance on insecticides is not a sustainable pest control strategy. Integrated Pest Management is the most desirable approach for insect pest management, and host plant resistance is considered to be a major component ofIPM. Development of suitable methodologies, understanding the mechanisms of resistance and identification of resistance sources and traits are some of the important steps involved in all host plant resistance programmes. In crucifers, all three types ofinsect resistance modalities (antixenosis, antibiosis and tolerance) are known to impart resistance to various insect pests. Cruciferous plants exhibit enormous variation in the level of resistance to insects. Resistant sources and traits have been identified for a number of insects. Genetic engineering and biotechnology offer great potential in the identification and transfer of resistance genes from distant relatives or even unrelated plant species. Studies are in progress to produce transgenic cruciferous crops with genes to produce Bacillus thuringiensis toxins and proteinase inhibitors, and to alter waxiness and glossiness characteristics to make the plants resistant to insect attack. Crop resistance has a number of advantages, one of them beingits excellent compatibility with IPM. It helps to promote the stability of the IPM system and to reduce the amount of pesticides used. Crop resistance has some limitations but there are ways to overcome a number of them. Plant breeders and biotechnologists should include insect resistance as a component of their crop improvement programme. Even partial resistance to insects will bring significant benefits, particularly when it is combined with other IPM components. In fact, when durability of resistanceis considered, partial resistance is preferable to total resistance. With greater collaboration and commitment from plant breeders, biotechnologists and entomologists, crop resistance could play a major role in the Integrated Pest Management of insect pests of cruciferous crops. Particular reference is made to Phyllotreta cruciferae and P. striolata feeding on canola [rape] in Canada and the USA.