Available Methods for Assessing Varietal Resistance to Sugarcane Stalk Borers

Sugarcane is semiperennial and produces considerable biomass, forming an ideal habitat for insects. Most insects do not affect crops, but some compete with humans for sugar and by-products. Sugarcane stalkborers are key pests of this crop worldwide because they feed directly on the vegetative tissues that store sucrose, allowing the introduction of micro-organisms that affect yield and quality. Conversely, the crop habitat permits the development of many beneficial arthropods that limit borers and keep other pests in check. The regular use of insecticides is often undesirable if natural enemies are to have maximum impact and other means have to be used to improve the control of borers. Varietal resistance might well be one of the most valuable methods for implementing an integrated pest management (IPM) strategy. For example, in the USA, predation and varietal resistance have been used with success for the management of the sugarcane borer Diatraea saccharalis (Bessin & Reagan, 1993). Similarly, this method is often favoured in studies carried out by the main sugarcane producing countries (Macedo et al.,1978; Leslie & Keeping, 1996; Allsopp et al., 1996; Mukunthan and Mohanasundaram, 1998; Kakakhel et al., 1999). This paper describes several methods for assessing varietal resistance, and results obtained by CIRAD entomologists with AVAILABLE METHODS FOR ASSESSING VARIETAL