Host preference of the burrowing nematode, Radopholus similis populations from India*

Host specificity study of 28 populations of Radopholus similis was done. Designated 17 host differentials to identify races of R. similis. The host differentials are coconut (Cv. Laccadive Micro), arecanut (Var. Mangala), banana (Cv. Njalipoovan and Var. Robusta), black pepper (Var. Panniyur-1), nutmeg (Cv. Local), clove (Cv. Local), cardamom (Cv. Vazhukka), tea War. Ca-150), coffee (Cv. San Ramon), avocado (Cv. Furte), citrus (Cv. Musambi), pineapple (Cvs. Mauritius and Kew), sweet potato (Var. H-268) and sugarcane (Vars. Co. 449 and Co. 997). Ten races of R. similis in south India were identified among the 28 populations on the basis of their multiplication on the 17 identified host differentials. Citrus, clove, pineapple and sugarcane var. Co. 997 were immune to all the 28 populations. Race I multiplied on all the 11 susceptible differentials. Nutmeg was immune to race II and nutmeg and tea were immune to race III. Race IV did not multiply on avocado and nutmeg. Black pepper was immune to race V. Race VI did not multiply on banana Cv. Njalipoovan but it multiplied on tissue cultured banana Var. Robusta and nutmeg. In addition to banana Cv. Njalipoovan race VII did not multiplied on sugarcane Var. Co. 449, avocado, coffee and tea. Race VIII did not multiply on 4 differentials viz. black pepper, sugarcane, tea and nutmeg. Arecanut, tea and nutmeg were immune to race IX. In addition to arecanut and nutmeg, race X did not multiply on black pepper.