Biological control of Fusarium Head Blight under greenhouse evaluation.

PALAZZINI J. M.; RAMIREZ M L; TORRES A. M.; CHULZE S.N.

Carlos Paz, Cordoba, Argentina

Congreso; Advances in research on toxigenic fungi and mycotoxins in South America ensuring food and feed safety in a myco-globe context.; 2006

Comision Europea-Universidad Nacional de Rio Cuarto

Fusarium Head Blight (FHB), primarily caused by Gibberella Zeae (anamorph = Fusarium graminearum), is a devastating disease that causes extensive yield and quality losses to wheat in humid and semi-humid regions of the world. This pathogen can produce on wheat grains mycotoxins such as zearalenone and trichothecens, becoming them unsuitable for human and animal consumption. A total of 354 bacterial strains were obtained from wheat anthers and screened for growth inhibition against six different G. zeae strains originally isolated from wheat cultivated in the main Argentinian wheat growing area. From the isolated strains 20 Bacillus spp. and 2 Actinomyces spp. were selected for greenhouse evaluation to determine their ability to reduce infection and colonization of G. zeae. Wheat seedlings (ProINTA Gaucho) 12 weeks old were coinoculated with a mixture of the bacterial inoculum (1 x 108 CFU/ml)  and G.zeae inoculum (1 x 105 conidia/ml). Five wheat heads were inoculated in the centrally located floret by treatment at anthesis stage. Wheat plants were maintained at 90% relative humidity for six days to ensure G. zeae infection and colonization, then humidity was reduced to 70% for ten days. After sixteen days wheat heads were visually evaluated to estimate FHB severity using a 0-to-100% scale. From the total strains evaluated 17 (77,2 %) were able to reduce G. zeae infection and colonization. Only three antagonist strains were able to control G. zeae infection and colonization in levels ranging from 51.2 % to 29 %.These strains were Bacillus spp. 166,218 and 263.