Biological control of striga hermonthica (Del.) benth using different formaulations of fusarium nygamai and fusarium (Abuharaz isolate) on sorghum bicolor (L.) monech

The efficacy of different granular formulation of Fusarium (Abuharaz isolate) and F. nygamai were evaluated in pot experiments in nursery at Abuharaz Faculty of Agriculture and Natural Resources, Wad Medani, Sudan. The tested formulation include: wheat-glutein matrix (pesta) and sodium alginate pillets amended with wheat, sorghum or yeast and some seed coating technique. The results obtained showed that both F. nygamai and Fusarium (Abuharaz isolate) controlled Striga effectively but Fusarium (Abuharaz isolate) was found better in controlling Striga. The application of Fusarium (Abuharaz isolate) using pesta technique was superior in reducing Striga emergence (up to 100%) and increasing sorghum plants height and dry weight by 70 and 213%, respectively. When alginate formulation of Fusarium (Abuharaz isolate) amended with yeast and sorghum as substrate, it reduced Striga incidence by 54 and 71 %, respectively. While F. nygamai formulated as alginate and amended with yeast and sorghum reduced Striga incidence by 46 and 50%, respectively. The seed coating techniques using fungal spores displayed non significant control level. To apply Koch postulates, Striga infected plants were investigated and showed numerous fungi including: Macrophomina spp., Asperigllus niger, Asperigllus flavus, Phoma spp., Alternaria spp., Curvularia spp., Hilmanthosporum spp. and Fusarium spp. But Fusarium species were the most dominant ones. To insure the safety of both isolate to sorghum seeds, harvested seeds of sorghum plants were investigated and revealed that Asperigllus niger, Asperigllus flavus, Rhizopus spp. and Penicillum spp. were present in both treated or untreated sorghum seeds but no Fusarium spp. was detected in the all tested sorghum seeds. In general, application of pesta formulation of Fusarium (Abuharaz isolate) gave the best Striga control and improved sorghum perfonnance. Therefore, the future work must focus on the using pesta for practical field work and should be integrated with other control measures