From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás an... more From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás and Tocantins states, Brazil, a collection of 230 monosporic isolates of Trichoderma spp. was established using TSM selective media. In order to select efficient isolates for biological control, dual culture tests were carried out on PDA media at 20 ºC for Sclerotinia sclerotiorum and at 25 ºC for Fusarium solani f.sp. phaseoli. From the whole collection, 50 isolates presented antagonism against F. solani and 111 isolates to S. sclerotiorum. The antagonism against both pathogens was found in only 10% of the isolates. Scanning electron microscopy assessments with seven in vitro selected isolates showed that not all promoted hyperparasitism on the pathogens, suggesting the existence of other mechanisms of antagonism, as antibiosis or competition.
The objective of this work was to evaluate the effects of crop cover, using Brachiaria ruziziensi... more The objective of this work was to evaluate the effects of crop cover, using Brachiaria ruziziensis mulch, Trichoderma harzianum 1306 spray treatment and of the interaction between these methods in reducing the density of Sclerotinia sclerotiorum inocula, in white mold incidence and in soybean yield. The evaluations were done from 2006 to 2008 in Jataí (Goiás State, Brazil), in a commercial crop with an average of 136.08 sclerotia m-2. In March and October 2006, 0, 0.5, 1 and 1.5 L ha-1 of T. harzianum 1306 (2x109 viable spores mL-1) were sprayed on plots cropped with B. ruziziensis or not. After controlling brachiaria with glyphosate (2,5 L ha-1) and sowing soybean 'M-Soy 6101' onto 10.1Mg ha-1 of its straw, 98% less apothecia were found in these treatments. The treatments with straw and 0.5 and 1 L ha-1 of T. harzianum presented 72.1 and 84.1% more parasited sclerotia respectively. 'M-Soy 6101' soybean yield in 2006/2007 was inversely proportional to the apothecia p...
From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás an... more From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás and Tocantins states, Brazil, a collection of 230 monosporic isolates of Trichoderma spp. was established using TSM selective media. In order to select efficient isolates for biological control, dual culture tests were carried out on PDA media at 20 ºC for Sclerotinia sclerotiorum and at 25 ºC for Fusarium solani f.sp. phaseoli. From the whole collection, 50 isolates presented antagonism against F. solani and 111 isolates to S. sclerotiorum. The antagonism against both pathogens was found in only 10% of the isolates. Scanning electron microscopy assessments with seven in vitro selected isolates showed that not all promoted hyperparasitism on the pathogens, suggesting the existence of other mechanisms of antagonism, as antibiosis or competition.
The objective of this work was to evaluate the effect of cropping systems and crops cultivated pr... more The objective of this work was to evaluate the effect of cropping systems and crops cultivated previously to common beans (Phaseolus vulgaris L.) on soil density and soil populations of Rhizoctonia spp. and Fusarium spp. Previous crops included the following legumes: Cajanus cajan,Stylosanthes guianensis cv. Mineirão and Crotalaria spectabilis; and the following grasses: Pennisetum glaucum (cv. BN-2, millet), Sorghum bicolor (cv. BR 304), Panicum maximum cv. Mombaça, Brachiaria brizantha cv. Marandu and a consortium of corn (Zea mays) and B. brizantha. Previous crops were planted in Brazil summer seasons (wet) of 2002, 2003 e 2004, and bean crop (cv. BRS Valente) was planted in the correspondent subsequent winters (dry) of 2003, 2004 and 2005, irrigated by central pivot. Crop residues were incorporated to the soil, in conventional tillage, and kept on the surface, in no tillage management. In general, soil populations of Fusarium spp. and Rhizoctonia spp. were higher in no tillage cropping system. Higher populations of Rhizoctonia spp. were found in heavier soils. Legume crop residue increased soil populations of Rhizoctonia spp. and Fusarium spp. and, therefore, Leguminosae should be avoided as previous crops to common beans, in both cultivation systems. Generally, Gramineae previous crops are supressive to soil populations of Rhizoctonia spp. and Fusarium spp.
Acanthospermum australe, a frequently weed infesting bean crops in the State of Goiás, Brazil, wa... more Acanthospermum australe, a frequently weed infesting bean crops in the State of Goiás, Brazil, was found infected by T. cucumeris under natural field conditions. Plants were severely affected and may be an important reservoir of inoculum for infection of cultivated crops. Pathogenicity of T. cucumeris in both A. australe and Phaseolus vulgaris was confirmed by Koch´s postulates.
From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás an... more From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás and Tocantins states, Brazil, a collection of 230 monosporic isolates of Trichoderma spp. was established using TSM selective media. In order to select efficient isolates for biological control, dual culture tests were carried out on PDA media at 20 ºC for Sclerotinia sclerotiorum and at 25 ºC for Fusarium solani f.sp. phaseoli. From the whole collection, 50 isolates presented antagonism against F. solani and 111 isolates to S. sclerotiorum. The antagonism against both pathogens was found in only 10% of the isolates. Scanning electron microscopy assessments with seven in vitro selected isolates showed that not all promoted hyperparasitism on the pathogens, suggesting the existence of other mechanisms of antagonism, as antibiosis or competition.
The objective of this work was to evaluate the effects of crop cover, using Brachiaria ruziziensi... more The objective of this work was to evaluate the effects of crop cover, using Brachiaria ruziziensis mulch, Trichoderma harzianum 1306 spray treatment and of the interaction between these methods in reducing the density of Sclerotinia sclerotiorum inocula, in white mold incidence and in soybean yield. The evaluations were done from 2006 to 2008 in Jataí (Goiás State, Brazil), in a commercial crop with an average of 136.08 sclerotia m-2. In March and October 2006, 0, 0.5, 1 and 1.5 L ha-1 of T. harzianum 1306 (2x109 viable spores mL-1) were sprayed on plots cropped with B. ruziziensis or not. After controlling brachiaria with glyphosate (2,5 L ha-1) and sowing soybean 'M-Soy 6101' onto 10.1Mg ha-1 of its straw, 98% less apothecia were found in these treatments. The treatments with straw and 0.5 and 1 L ha-1 of T. harzianum presented 72.1 and 84.1% more parasited sclerotia respectively. 'M-Soy 6101' soybean yield in 2006/2007 was inversely proportional to the apothecia p...
From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás an... more From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás and Tocantins states, Brazil, a collection of 230 monosporic isolates of Trichoderma spp. was established using TSM selective media. In order to select efficient isolates for biological control, dual culture tests were carried out on PDA media at 20 ºC for Sclerotinia sclerotiorum and at 25 ºC for Fusarium solani f.sp. phaseoli. From the whole collection, 50 isolates presented antagonism against F. solani and 111 isolates to S. sclerotiorum. The antagonism against both pathogens was found in only 10% of the isolates. Scanning electron microscopy assessments with seven in vitro selected isolates showed that not all promoted hyperparasitism on the pathogens, suggesting the existence of other mechanisms of antagonism, as antibiosis or competition.
The objective of this work was to evaluate the effect of cropping systems and crops cultivated pr... more The objective of this work was to evaluate the effect of cropping systems and crops cultivated previously to common beans (Phaseolus vulgaris L.) on soil density and soil populations of Rhizoctonia spp. and Fusarium spp. Previous crops included the following legumes: Cajanus cajan,Stylosanthes guianensis cv. Mineirão and Crotalaria spectabilis; and the following grasses: Pennisetum glaucum (cv. BN-2, millet), Sorghum bicolor (cv. BR 304), Panicum maximum cv. Mombaça, Brachiaria brizantha cv. Marandu and a consortium of corn (Zea mays) and B. brizantha. Previous crops were planted in Brazil summer seasons (wet) of 2002, 2003 e 2004, and bean crop (cv. BRS Valente) was planted in the correspondent subsequent winters (dry) of 2003, 2004 and 2005, irrigated by central pivot. Crop residues were incorporated to the soil, in conventional tillage, and kept on the surface, in no tillage management. In general, soil populations of Fusarium spp. and Rhizoctonia spp. were higher in no tillage cropping system. Higher populations of Rhizoctonia spp. were found in heavier soils. Legume crop residue increased soil populations of Rhizoctonia spp. and Fusarium spp. and, therefore, Leguminosae should be avoided as previous crops to common beans, in both cultivation systems. Generally, Gramineae previous crops are supressive to soil populations of Rhizoctonia spp. and Fusarium spp.
Acanthospermum australe, a frequently weed infesting bean crops in the State of Goiás, Brazil, wa... more Acanthospermum australe, a frequently weed infesting bean crops in the State of Goiás, Brazil, was found infected by T. cucumeris under natural field conditions. Plants were severely affected and may be an important reservoir of inoculum for infection of cultivated crops. Pathogenicity of T. cucumeris in both A. australe and Phaseolus vulgaris was confirmed by Koch´s postulates.
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