For isolation, bluish-black-stained infected rubberwood pieces were collected from sawmills in the Thrissur District, Kerala State, India. Wood pieces were washed thoroughly in running water and cleaned with alcohol. Small pieces for inoculation were taken from the interior infected portion and surface-sterilized with 0.01% of HgCl2 for 50 s, washed thrice in sterile distilled water and dried. Inoculations were done on PDA medium [18] with streptomycin (300 mg/l) to avoid bacterial contamination and incubated at 28 ± 2 °C for 7 days. The isolated cultures were confirmed as L. theobromae by the morphological and microscopical descriptions provided [15]. Pure fungal cultures were isolated and maintained on PDA slants. The cultures of sapstain fungus (L. theobromae) thus obtained were used for further studies.