PATHOGENICITY TEST OF LASIODIPLODIA THEOBROMAE ISOLATES FROM SIX HOST PLANTS ON RUBBER AND THEIR PHYLOGENY ANALYSIS

Abstract

Stem cankers caused by the fungus Lasiodiplodia theobromae on rubber plant ( Hevea brasiliensis Muel Arg.) is a new disease and has not yet been reported in Indonesia. L. theobromae is a polyfag fungus and has a wide host range. The fungus is able to live as a saprophyte on leaves, dead wood, plant debris, and can also be parasitic on some plants. The variability of disease symptoms and host range of the fungus indicate the probability that this species has several strains. The strains have different virulence levels and symptoms on each host. There has been no information whether a strain of the fungus L. theobromae from any particular host plant can infect rubber plant. This study was carried out to determine the symptoms caused by the fungus L. theobramae from several hosts on rubber plants and phylogenetic analysis of L. theobramae from several host plants. The results showed that the six isolates inoculated on rubber plants i.e isolates from mango, banana, guava, avocado, rubber and citrus produced the disease symptoms and there are no differences in symptoms except for the isolate from rubber, where the disease severity appeared to be higher and it caused the death of the inoculated branch. Keyword: Lasiodiplodia theobromae, Hevea brasiliensis , canker disease, phylogeny analysis, pathogenicity