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