Evaluation of screening methods against Corynespora leaf fall disease of rubber (Hevea brasiliensis).

摘要

Identification of resistant clones is a major strategy in the management of Corynespora leaf fall disease (CLFD) of rubber. Several methods to identify resistance/susceptibility were examined in this study. There were significant variations in the mean lesion scores of different clones when evaluated by laboratory based in vitro assays. When screened in a bud wood nursery, the lesion types agreed with the symptoms observed in field plants. Analysis of results of clones screened under natural conditions showed that 85% of the clones in the Rubber Research Institute of Sri Lanka (RRISL) recommendation list can be ranked as resistant. The results of this investigation suggest that laboratory based in vitro screening methods should be used only for preliminary data. Field experiments, though dependable, take a considerably longer period. As such the bud wood nursery experiments which takes a much shorter time can be recommended to screen planting material for resistance or susceptibility to CLFD.