Natural rubber id a versatile industrial raw material which provides numerous uses to human beings.Its social implications are critical due to the fact that over twenty million people are dependent on rubber and rubber based industries.However,Corynespora leaf fall disease(CLFD) has emerged as a serious threat to the industry,destroying thousand of hectares in many rubber growing countries like Sri Lanka,Malaysia,Indonesia and Thailand.During the initial period,C.cassiicola was considered as a weak pathogen capable of attracking only the nutrient deficient seedlings(Newsam 1961).During its worldwide epidemic in the 1980's two prestigiousclones,RRIC103&RRIM725 were wiped out from the major rubber growing countries.Since then,this pathogen has become a grave threat to the industry,attacking many high yielding clones which were considered as resistant or moderately resistant during the first epidemic.This sudden susceptibility of most of the leading clones which contribute to more than 60% of the natural rubber production has raised serious concern among the stakeholders.