EVALUATION OF PHYLLOPLANE , CAULOPLANE AND RHIZOSPHERE BACTERIA FOR MULTIPLE ANTAGONISM AGAINST FIVE MAJOR PATHOGENS OF RUBBER (HEVEA BRASILIENSIS)

Abstract

Bacteria associated with phylloplane, cauloplane and rhizosphere of rubber (Hevea brasiliensis, clones RRII 105and PB 260) from six rubber growing regions in south-western India were isolated during monsoon, post-monsoon and summer seasons. These isolates were evaluated for antagonism against five major pathogens of rubber viz. Corynespora cassiicola, Colletotrichum acutatum, Phytophthora meadii, Corticium salmonicolor and Phellinus noxius.  Out of the 118 isolates screened, 11   showed antagonism against all the five and 18 against a minimum of four of the pathogens tested. Among these, three phylloplane isolates (B24, B54 and B61) showed high inhibition of at least three pathogens. The mechanism of antagonism included production of volatile compounds, HCN and siderophores. In vivo evaluation of the three selected isolates for protection against leaf diseases caused by C. cassiicola and    C. acutatum on young rubber plants (clone RRII 105) grown in polybags confirmed their efficacy. Prior inoculation of the antagonistic bacterial isolates was more effective in reducing disease intensity.