|Schisler, David - Dave|
Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 10/1/2004
Publication Date: 11/1/2004
Citation: Kolombet, L.V., Sokolov, M.S., Chuprina, V.P., Schisler, D.A., Samuels, G.J. 2004. Combination of biological products to control fusarium head blight in wheat [abstract]. Proceedings of the International Scientific and Practical Conference. Biological Plant Protection as a Basis for Stabilizing Agroecosystems. Krasnodar, Russia. Book 3, p. 217-218. Interpretive Summary:
Technical Abstract: Concomitant with the increase in wheat cultivation across the globe has been a rise in the importance of Fusarium head blight (FHB) caused by several species of the fungus Fusarium. Destructive epidemics of this disease have recently occurred in 1982, 1986, and 1990-1996 in the United States and in the south of Russia in 1982, 1984, 1988, and 1992. Not only does FHB reduce grain yields, but the causal agent can also produce mycotoxins such as deoxynivalenol (DON) and its derivatives (3-As-DON, 15-As-DON), T-2 toxin and zearalenone which can contaminate grains and grain products. Standard means to control FHB (cultural control methodologies, chemical pesticides, and FHB resistant varieties) have little effect or are not practical and rarely reduce the accumulation of mycotoxins in grain. We have developed a new technique to reduce FHB using biological preparations. Wheat seeds are pretreated with a biofungicide "Mycol" in combination with spraying wheat plants during flowering with a yeast preparation. The active agent in Mycol is Trichoderma asperellum strain GJS 03-35. This strain shows hyperparasitic activity against a wide spectrum of plant pathogens, including Fusarium graminearum, a causative agent of FHB in wheat. Experiments conducted in the United States demonstrated that spraying wheat plants during flowering with the patented yeast Cryptococcus nodaensis OH 182.9 (NRRL Y-30216) consistently reduces FHB development. Tests of the Mycol preparation and the yeast OH 182.9 (EOD) have been performed on the spring wheat "Ivolga" in greenhouse conditions (the Moscow region) and on the winter wheat "Kupava" in field trials in the North Caucasian region. The effect of single or combined biological treatments on FHB disease severity and incidence, as well as mycotoxin accumulation in wheat grains was studied. Mycol (in concentrations 0.1; 0.5; 1.0; 2.0 kg / 1 metric ton of seeds) was used for wheat seed pretreatment. The yeast preparation EOD (2.0x10**-7 cfu/ml) was applied by spraying wheat plants during flowering. Chemical pesticides (Raxyl, TMTD) and a biological preparation Agat-25K were used as alternative control seed treatments. In greenhouse experiments, inoculations of heads with either biological preparation 4 h prior to inoculation with conidia of F. graminearum significantly reduced FHB severity. Application with Mycol reduced DON in wheat grains by 6- to 11-fold. EOD alone or, to a lesser extent, in combination was also highly effective in reducing DON content. For treatments consisting of Mycol and EOD, 1000 grain weights were equivalent or higher than for control plants (both infected, and not infected). Wheat seeds obtained from the plants protected by these biological preparations germinated rapidly and possessed high germination rates compared to the FHB control. In field trials, Mycol treatments clearly reduced FHB symptoms, apparently providing an immunizing effect against FHB. Mycol reduced FHB severity and enhanced yield of the wheat varieties used. The effect of Mycol used at a minimum test-dose (0.1 kg / 1 ton) was not so pronounced. The greatest reduction of FHB development was observed at a dose of Mycol of 1.0 kg per 1 ton of seeds used in combination with EOD spraying. Experimental results support the contention that this technology holds promise for reducing Fusarium head blight.