Growth chamber trials were performed to investigate optimal conditions for the small scale production of isolate M12-4A of Fusarium oxysporum on substrate materials that are locally available to subsistence farmers in West Africa. Field trials were conducted in Mali to evaluate the effectiveness of F. oxysporum for the control of Striga hermonthica and to determine the host range of F. oxysporum. F. oxysporum grew and colonized substrates over a range of temperatures (24, 28 and 32 C). Chopped sorghum straw pieces, straw fibres, and glumes supported abundant mycelial growth. Full colonization of the substrates was observed within 10 days. Production of infective propagules (microconidia and macroconidia) was optimum at 28 C. Optimum wetness of the substrates was obtained by soaking straw or glumes overnight. In field studies, the incorporation of 2.6 g of dried ground straw inoculum per sorghum seed pocket (120 cm$ sp2$), at a depth of 5 or 10 cm, resulted in a 60% reduction of emerged S. hermonthica 82 days after sowing. At harvest, biomass of Striga was also reduced by 70% and sorghum grain yield was almost doubled compared with the control. Sorghum, millet, maize, rice, fonio, cotton, cowpea, groundnut, okra and sorrel were immune to isolate M12-4A.

Fusarium oxysporum M12-4A fungus is being evaluated for the biocontrol of Striga hermonthica, a parasitic weed of African cereal crops. The production of M12-4A inoculum was assessed in four Malian villages using local technology and substrates. A delivery system using arabic gum to temporarily glue inoculum powder onto the crop seed was tested. In controlled conditions, coating of sorghum seeds with arabic gum and inoculum powder did not affect seed germination or inoculum viability. However, one week at 40°C significantly decreased the viability of the inoculum by 31%. Fungus growth and chlamydospore germination were also reduced by temperatures of 34 and 36°C. M12-4A was susceptible to the fungicide thiram (ED50 = 38.5mug). Field trials were conducted in Mali to evaluate the large-scale efficacy of the seed coating technology. F. oxysporum M12-4A was detected from some S. hermonthica tissue and soil samples using specific primers and Real Time PCR.

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Thesis (M.Sc.). / Written for the Dept. of Plant Science. Title from title page of PDF (viewed 2008/12/10). Includes bibliographical references.

Thesis (Ph.D.)--Flinders University, School of Biological Sciences. / Typescript bound. Includes bibliographical references: (p. 237-268) Also avaialable online.

Thesis (M.S.)--Ohio State University, 1986. / Includes bibliographical references (leaves 102-106). Available online via OhioLINK's ETD Center