and approximately 10 u03bcl of the suspension are used to inoculate the plant seed head the plants are then cultivated under conditions of near 100 relative humidity conducive to infection by the fungus for a period of about 3 days after a period of time sufficient for noticeable development of the disease usually at least about 2 weeks post inoculation microbes used to treat seed heads that do not develop visible symptoms of fhb are selected for subsequent evaluation organisms selected in the plant bioassay described above are optionally subjected to a second more highly replicated plant seed head bioassay similar to the first the organisms are again grown on a suitable medium until sufficiently expanded for use in the bioassay however in this second plant bioassay it is preferable to grow the strains in liquid culture since this practice is widely used in industry and antagonists must show bioefficacy when grown under liquid culture conditions colonized broth containing cells of individual strains and a conidial suspension of f graminearum are used to inoculate seed heads as previously described the cells and conidial suspension may be precombined prior to inoculation as in the first plant bioassay microbes used to treat seed heads that do not develop visible symptoms of fhb are selected as candidate antagonists confirmation of antagonist efficacy in controlling f graminearum can be made in scaled up greenhouse studies or in field studies in which flowering plants are treated with cells of the test strains before during or.