Long-term dry preservation of viable mycelia of two mycoherbicidal organisms

The production of large amounts of fungal spores for preservation and formu lation are considered constraints to effective use of fungal biocontrol age nts. Few successful attempts have been made to store fungal mycelia alone. Late log-phase liquid fermenter cultured isolated mycelia of two Fusarium s pp. specific to the parasitic broomrapes (Orobanche spp.) from fermenters w ere formulated in alginate beads or in 'Stabileze' (starch, sucrose, corn o il, and silica) and air-dried. 'Stabileze' formulations exhibited <30% loss of mycelial viability for >9 months and retained pathogenicity to the weed for over a year, while mycelia harvested earlier, and conidia from liquid culture exhibited >40% loss of viability. Mycelia from liquid culture yield ed >20 times more colony forming units (cfu) of F. arthrosporioides and >2 times more cfu of F. oxysporum than spores at late log phase. Efficient for mulation of mycelia should significantly change the economics of biocontrol . (C) 2000 Elsevier Science Ltd. All rights reserved.