Efficacy of CLO-1 biofungicide in suppressing perithecial production by Gibberella zeae on crop residues

Fusarium head blight (FHB), caused by Gibberella zeae (anamorph: Fusarium graminearum), is a destructive disease of cereals. Previous studies demonstrated that Clonostachys rosea strain ACM941 is an antagonist of G. zeae that parasitizes the pathogen and reduces FHB severity in wheat. The objective of this research was to evaluate the efficacy of CLO-1, a formulated product of ACM941, for reducing perithecial production on various crop residues in comparison with the registered fungicide Folicur (tebuconazole) under field conditions. When applied on G. zeae inoculated corn, soybean and wheat residues in the spring of 2009 and 2010, CLO-1 significantly inhibited perithecial production on all crop residue types, reducing daily perithecial production (DPP) by 93.1% on corn residue, 94.4% on soybean residue and 84.0% on wheat residue, compared with the untreated control. When applied on naturally infected wheat residues in the autumn of 2009 and 2010, CLO-1 significantly reduced DPP in the following growing season by 72.3% on peduncles, 51.0% on spikelets and 57.2% on stems. These effects were numerically better but not significantly different from those achieved by Folicur fungicide used as a positive control in the same experiments. Results from this study suggest that CLO-1 is a promising biofungicide against G. zeae and may be used as a control measure to reduce the initial inoculum of FHB in an integrated FHB management programme.