During the last century, as the area of wheat grown under advanced grain husbandry has increased worldwide, so too has the importance of Fusarium ear scab (FES) (synonym, Fusarium head blight) caused by several specie...During the last century, as the area of wheat grown under advanced grain husbandry has increased worldwide, so too has the importance of Fusarium ear scab (FES) (synonym, Fusarium head blight) caused by several species of the fungus Fusarium. Yield losses due to FES can total 20%-40% and more depending on climatic conditions. During the last twenty years epidemics of FES in cereals have become chronic all over the world, including the United States and Russia. The most destructive of these were observed in 1982, 1986, 1990-1996 in USA and in the south of Russia in 1982, 1984, 1988, 1992. The harmful effect of FES is manifested not only in reduced grain yields, but also in the contamination of grains and grain products with mycotoxins, such as deoxynivalenol (DON) and its derivatives (3-alfa acetyl-DON, 15-alfa acetyl-DON), T-2 toxin and zearalenone. Standard means to control FES (cultural control methodologies, chemical pesticides, and FES 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 FES using biological preparations. The technique utilizes wheat seed pretreatment with a biofungicide “Mycol” in combination with spraying wheat plants during flowering with a yeast preparation. Technology for production of Mycol on the basis of Trichoderma asperellum strain GJS 03-35 (systematics by Samuels) has been developed. This strain shows hyperparasitic activity against a wide spectrum of plant pathogens, including Fusarium graminearum, a causative agent of FES 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) reliably reduces FES 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. An isolate of F. graminearum was used to insure adequate levels of disease development in greenhouse and field experiments. FES disease severity and incidence, as well as mycotoxin accumulation in wheat grains was studied for single or combination treatments with the biological preparations. Mycol (in concentrations 0.1, 0.5, 1.0, 2.0 kg/t of seeds) was used for wheat seed pretreatment. The yeast preparation EOD (2.0×107 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 FES 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 FES control. In field trials, Mycol treatments clearly reduced FES symptoms, apparently providing an immunizing effect against FES. Mycol reduced FES severity and enhanced yield of the wheat varieties used. The effect of Mycol used at a minimum test-dose (0.1 kg/t) was not so pronounced. The greatest reduction of FES development was observed at a dose of Mycol of 1.0 kg per 1 t of seeds used in combination with EOD spraying. Experimental results support the contention that the offered technology has good prospects in controlling wheat Fusarium ear scab.展开更多
Biological protection of plants: definition and objectives. Technologically, biological protection of plants (hereinafter bioprotection) is a high agricultural technology involving agricultural landscape approach and ...Biological protection of plants: definition and objectives. Technologically, biological protection of plants (hereinafter bioprotection) is a high agricultural technology involving agricultural landscape approach and basee on an ecological imperative, namely “use living beings against living beings”. In a wide sense, present-day bioprotection is a fundamental and applied field of knowledge providing harmless suppression of harmful agents during cultivation and storage of agricultural crops by use natural and (or) artificially constructed organisms (including genetically modified ones having pesticidal properties) and products of their live cycle. The overall objective of bioprotection consists in producing harmless, profitable and high-quality vegetative raw material, food, fodder. At the same time, bioprotection agrotechnologies are important environment forming and environment maintaining factors, steady and positively influencing the health of both rural ethnos, and agrosphere as a whole. Realization of integrated bioprotection approaches should provide minimum destruction of beneficial and non-target organisms, excluding the succession of harmful species and appearance of species resistant to biocontrol agents. 2. Theoretical foundation of bioprotection. The following postulates and imperatives of biosphere science, agrarian and social ecology make the scientific basis of bioprotection: “The Nature knows the how and why of things better”; Steady, balanced development of agrosphere (proceeding from a presumption of life support) is based on biocentrism and biosystem relations, or consortism of its consorbents; Control of the agrosphere by human beings could be effective only in case of primary realization of biocenotic regulation; Biocenotic regulation, dynamics of the number and species diversity of agrosphere is realized through trophically similar cenoconsorcia and tritrophic systems, that provides maintenance and preservation of trophically proved critical level of harmful species; Biotic and man-caused effects on argosphere are regularly registered and the degree of these effects on non-target biota is comprehensively estimated, operative measures to prevent its elimination are taken, if necessary. Thus, artificial agrocenoses and agroecosystems are immanent components of the agrospehere. Functioning of their bioresources meets the same laws of the Nature, as the functioning of the biota of natural ground ecosystems. When agrocenoses and agroecosystems make a single whole with the elements of preserved natural ecosystems, reproduction of bioresources, their protection against expansion of competitive and cosmopolitan species are realized at a level of steadily functioning agrocenoconsorcia, where “living beings protect living beings”. 3. Bioprotection and agrosphere. Present-day bioprotection is based on agrolandscape approaches. The major global function of the agrolandscape involves utilization of maximum quantity of solar energy. Modern geosystemic definition of the agrolandscape emphasizes not only its production abilities, but also its social and design-aesthetic functions: “... is an existing geosystem anthropogenically modified for agricultural use and formed with the purpose of the most effective and ecologically safe use of natural and anthropogenic resources for manufacturing economically and socially reasonable quantity of agricultural production and creation of the welfare and spiritual environment for harmonious development of humans” (A.V. Zaharenko, 2004) . The paradox is, that current plant growing (initially based on the use of gratuitous, inexhaustible solar energy and renewed resources of agrosphere) has turned in the most resource uneconomic branch of economy by the beginning of XXI century. Therefore agricultural technologies, including protection of plants, should mostly use renewable, instead of exhaustible resources and not renewable sources of raw material and energy, materialized in agrochemicals, chemical pesticides, oil展开更多
文摘During the last century, as the area of wheat grown under advanced grain husbandry has increased worldwide, so too has the importance of Fusarium ear scab (FES) (synonym, Fusarium head blight) caused by several species of the fungus Fusarium. Yield losses due to FES can total 20%-40% and more depending on climatic conditions. During the last twenty years epidemics of FES in cereals have become chronic all over the world, including the United States and Russia. The most destructive of these were observed in 1982, 1986, 1990-1996 in USA and in the south of Russia in 1982, 1984, 1988, 1992. The harmful effect of FES is manifested not only in reduced grain yields, but also in the contamination of grains and grain products with mycotoxins, such as deoxynivalenol (DON) and its derivatives (3-alfa acetyl-DON, 15-alfa acetyl-DON), T-2 toxin and zearalenone. Standard means to control FES (cultural control methodologies, chemical pesticides, and FES 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 FES using biological preparations. The technique utilizes wheat seed pretreatment with a biofungicide “Mycol” in combination with spraying wheat plants during flowering with a yeast preparation. Technology for production of Mycol on the basis of Trichoderma asperellum strain GJS 03-35 (systematics by Samuels) has been developed. This strain shows hyperparasitic activity against a wide spectrum of plant pathogens, including Fusarium graminearum, a causative agent of FES 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) reliably reduces FES 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. An isolate of F. graminearum was used to insure adequate levels of disease development in greenhouse and field experiments. FES disease severity and incidence, as well as mycotoxin accumulation in wheat grains was studied for single or combination treatments with the biological preparations. Mycol (in concentrations 0.1, 0.5, 1.0, 2.0 kg/t of seeds) was used for wheat seed pretreatment. The yeast preparation EOD (2.0×107 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 FES 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 FES control. In field trials, Mycol treatments clearly reduced FES symptoms, apparently providing an immunizing effect against FES. Mycol reduced FES severity and enhanced yield of the wheat varieties used. The effect of Mycol used at a minimum test-dose (0.1 kg/t) was not so pronounced. The greatest reduction of FES development was observed at a dose of Mycol of 1.0 kg per 1 t of seeds used in combination with EOD spraying. Experimental results support the contention that the offered technology has good prospects in controlling wheat Fusarium ear scab.
文摘Biological protection of plants: definition and objectives. Technologically, biological protection of plants (hereinafter bioprotection) is a high agricultural technology involving agricultural landscape approach and basee on an ecological imperative, namely “use living beings against living beings”. In a wide sense, present-day bioprotection is a fundamental and applied field of knowledge providing harmless suppression of harmful agents during cultivation and storage of agricultural crops by use natural and (or) artificially constructed organisms (including genetically modified ones having pesticidal properties) and products of their live cycle. The overall objective of bioprotection consists in producing harmless, profitable and high-quality vegetative raw material, food, fodder. At the same time, bioprotection agrotechnologies are important environment forming and environment maintaining factors, steady and positively influencing the health of both rural ethnos, and agrosphere as a whole. Realization of integrated bioprotection approaches should provide minimum destruction of beneficial and non-target organisms, excluding the succession of harmful species and appearance of species resistant to biocontrol agents. 2. Theoretical foundation of bioprotection. The following postulates and imperatives of biosphere science, agrarian and social ecology make the scientific basis of bioprotection: “The Nature knows the how and why of things better”; Steady, balanced development of agrosphere (proceeding from a presumption of life support) is based on biocentrism and biosystem relations, or consortism of its consorbents; Control of the agrosphere by human beings could be effective only in case of primary realization of biocenotic regulation; Biocenotic regulation, dynamics of the number and species diversity of agrosphere is realized through trophically similar cenoconsorcia and tritrophic systems, that provides maintenance and preservation of trophically proved critical level of harmful species; Biotic and man-caused effects on argosphere are regularly registered and the degree of these effects on non-target biota is comprehensively estimated, operative measures to prevent its elimination are taken, if necessary. Thus, artificial agrocenoses and agroecosystems are immanent components of the agrospehere. Functioning of their bioresources meets the same laws of the Nature, as the functioning of the biota of natural ground ecosystems. When agrocenoses and agroecosystems make a single whole with the elements of preserved natural ecosystems, reproduction of bioresources, their protection against expansion of competitive and cosmopolitan species are realized at a level of steadily functioning agrocenoconsorcia, where “living beings protect living beings”. 3. Bioprotection and agrosphere. Present-day bioprotection is based on agrolandscape approaches. The major global function of the agrolandscape involves utilization of maximum quantity of solar energy. Modern geosystemic definition of the agrolandscape emphasizes not only its production abilities, but also its social and design-aesthetic functions: “... is an existing geosystem anthropogenically modified for agricultural use and formed with the purpose of the most effective and ecologically safe use of natural and anthropogenic resources for manufacturing economically and socially reasonable quantity of agricultural production and creation of the welfare and spiritual environment for harmonious development of humans” (A.V. Zaharenko, 2004) . The paradox is, that current plant growing (initially based on the use of gratuitous, inexhaustible solar energy and renewed resources of agrosphere) has turned in the most resource uneconomic branch of economy by the beginning of XXI century. Therefore agricultural technologies, including protection of plants, should mostly use renewable, instead of exhaustible resources and not renewable sources of raw material and energy, materialized in agrochemicals, chemical pesticides, oil
