Biological control of toxigenic fungi: current knowledge and mycored contribution

KOLH J; ACHLEITNER, D; BANDYOPADHYAY, R; CHULZE, , S.N; MORETTI, A

Martina Franca

Congreso; ISM MycoRed International Conference Europe 2013. Global Mycotoxin Reduction Strategies; 2013

International Society of Mycotoxicology

Biological control of plant diseases is o sustainable olternative or complement to chemicalcontrol. The number of registered biological control products in Europe increosed during the last years. The woridwide market share of biological control products for crop protection Is estimated by 3.5 %. The current annual growth rata of the biocontrol market is estimated by 14 %. This results in an increasing demand for economically viable biocontrol Solutions for exploitation by the growing biocontrol industn/. Biocontrol agents potentially ca n be used in the integrated pest nnanagement (IPM) of toxigenic plant pathogens with the objective to reduce the risk of mycotoxin contamination in food or feed. For example, onfagonists ca n reduce pathogen populations in soil and crop residues or ca n protect crops from infectlon by the pathogens. In the EU project MycoRed, biocontrol options for control of toxigenic Fusarium spp. and Aspergillus spp. were investigated In several cropping systems. Fusarium spp. can cause ear rot in cereals including maize resulting in losses in yield and quality due to contamination of the grain with deoxynivalenol (DON) and other mycotoxins. Two biological control strategies were investigated in MycoRed: Treatments of stubble of maize and wheat to reduce the amount of primary inoculum in the fieId and the application of onfagonists to ears during flowering. Significant reduction of Fusarium colonization of wheat stubble was achieved by spray applications of tw o Clonostachys rosea isolates in triáis carried out in Argentina during two years at two locations. Applications of the same onfagonists on maize stubble in experiments in The Netherlonds and Itaiy were not effective. In triáis in Argentina, formulated products of the yeasts Bacillus subfiUs RC 218 a nd Brevibacillus sp. RC 263 were applied to wheat ears during anthesis. Disease severity was reduced significantly by 50%. No DON was detecte d in harvested groin ofter biocontrol treatments, but more than >1000 \jg/kg DON were found in the control treatments. Control of toxigenic Aspergillus flavus was achieved by application of Aflasafe containing atoxigenic A. flavus isolates. In a huge series of fieId trials in Nigeria, aflatoxin concentration in maize and groundnut was reduced at harvest and afterstorage by 60-96 %. This consistent effect of competitive exclusión of toxigenic strains by atoxigenic strains was carried over in the fieId from one season to the next. Promising results were olso achieved by applications of anfagonists against Aspergillus section Nigri in grapes and A.flavus in groundnut in fieId trails in Argentina. For commercial applications, anfagonists must fulfill many more criterio besides their pofentiol to control diseoses. For a set of the onfagonists used in MycoRed, the economic feosibility of large scale production ond of lounching the biocontrol ogents to the market has been evaluated.