STUDIES ON THE INTEGRATED CONTROL OF MAGROPHOMINA PHASEOLINA (TASSI) GOID

The sclerotia of Macrophomina phaseolina increased in soil planted under cotton, Okara or sunflower. Sunflower showed high susceptibility (100%) followed by Okara (69%) and cotton (47%). Number of sclrotia declined by 51% in cotton-Iucerne-cotton, 54% in cotton-wheat-cotton, 36% in cotton-mustard-mung-cotton, 34% in cotton-wheat-dhaincha-cotton, 47% in cotton-garlic-cotton, 33% in cotton-onion-cotton and 27% in cotton-wheat-ginger-cotton rotations as compared to 19-23% reduction in dry fallow. Paddy cultivation in Macrophomina infested field showed promise in the inactivation of sclerotia from soil since number of sclerotia declined by 83% at Karachi and were eliminated at Lahore after 12 weeks sampling. Use of green manure @ 1% w/w was more effective in reducing number of sclerotia by 46% in dhaincha, 35% in moth and 43% in berseem. Similarly addition of dry organic substrate @ 5% w/w reduced number of sclerotia by 50% in kallar grass and 37% in saw dust amendment. Control of Macrophomina infection on sunflower observed was 69% in sawdust and 45% in kallar grass amendments. Amendment of soil with fertilizers @ 10% w/w showed a rduction in number of sclerotia within 2 weeks in higro (100%), plant food (91%), fish meal (95%) and bone meal (73%). Complete control of Macrophomina infection was observed when higro, fish meal or plant food were used. The reduction in population of M. phaseolina and its infection on mung seedlings may be due to greater proportion of actinomycetes in higro, fish meal and plant food\ud \ud Microbial antagonists multiplied on wheat straw applied in furrows @ 0.1% w/w reduced Macrophomina infection on mung by 86% in Paecilomyces lilacinus, 53% in Streptomyces sp. , 43% in Aspergillus Candidus and Rhizobium leguminosarum as compared to control. Organic amendments with kallar grass previously inoculated with microbial antagonists were more effective than used alone and Macrophomina infection on sunflower reduced by 52% in Arachniotus sp., 50% in Bacillus sp., and 54% in Streptomyces sp. Sunflower stem or root pieces previously colonized by Macrophomina phaseolina and treated with Trichoderma harzianum, Gliocladium virens or Paecilomyces did not survive after 1 week burial in soil showing greater competitive ability of the antagonists. Coating seeds with microbial antagonists give promising results against Macrophomina infection on mung, sunflower, okara, cotton, gram and mustard both under laboratory and field conditions. Complete control of Macrophomina infection was observed where T. harzianum and Streptomyces sp., were used on gram and mustard., Aspergillus candidus on gram; Rhizobium sp., on okra were effective under field conditions. It pot experiment bacterization of seeds with Rhizobium Japonicum reduced infection by 60% mung, 47% on okara and 38% on sunflower; R. leguminosarum by 48% on sunflower and 57% on mung; R.meliloti by 71% on mung seedlings as compared to untreated control\ud \ud A 7 day mulching treatment proved to be the most effective method to eradicate the sclerotial propagules from soil with 100% control of Macrophomina infection on test plants. The sclerotia of M. Phaseolina which survived at 20cm depth showed greater vulnerability to antagonistic micro-organisms, where reduction in population was 40% in Streptomyces sp., and 25% in Bacillus sp., as compared to 20% in control and eliminated when brought back to the surface followed by another 4 or 7 day mulch treatmen