Corbat420
Well-Known Member
What are Trichoderma?
Trichoderma spp. are fungi that are present in nearly all soils and other diverse habitats. In soil, they frequently are the most prevalent culturable fungi. They are favored by the presence of high levels of plant roots, which they colonize readily. Some strains are highly rhizosphere competent, i.e., able to colonize and grow on roots as they develop. The most strongly rhizosphere competent strains can be added to soil or seeds by any method. Once they come into contact with roots, they colonize the root surface or cortex.
View attachment 2116314
(Fig. 1: Cultures of Trichoderma harzianum strain T-22 (KRL-AG2) growing on potato dextrose agar. The white areas do not contain spores, while the green areas are covered with dense masses of spores (conidia).)
In addition: Trichoderma attack, parasitize and otherwise gain nutrition from other fungi. Since Trichoderma grow and proliferate best when there are abundant healthy roots, they have evolved numerous mechanisms for both attack of other fungi and for enhancing plant and root growth.
Pathogens controlled: So far as the author is aware, different strains of Trichoderma control every pathogenic fungus for which control has been sought. However, most Trichoderma strains are more efficient for control of some pathogens than others, and may be largely ineffective against some fungi. The recent discovery in several labs that some strains induce plants to "turn on" their native defense mechanisms offers the likelihood that these strains also will control pathogens other than fungi.
Pesticide susceptibility: Trichoderma possess innate resistance to most agricultural chemicals, including fungicides, although individual strains differ in their resistance. Some lines have been selected or modified to be resistant to specific agricultural chemicals. Most manufacturers of Trichoderma strains for biological control have extensive lists of susceptibilities or resistance to a range of pesticides.
Plant growth promotion: For many years, the ability of these fungi to increase the rate of plant growth and development, including, especially, their ability to cause the production of more robust roots has been known. The mechanisms for these abilities are only just now becoming known.
Some of these abilities are likely to be quite profound. Recently, we have found that one strain increases the numbers of even deep roots (at as much as a meter below the soil surface). These deep roots cause crops, such as corn, and ornamental plants, such as turfgrass, to become more resistant to drought.
Perhaps even more importantly, our recent research indicates that corn whose roots are colonized by Trichoderma strain T-22 require about 40% less nitrogen fertilizer than corn whose roots lack the fungus. Since nitrogen fertilizer use is likely to be curtailed by federal mandate to minimize damage to estuaries and other oceanic environment (there are a number of other sites on the web dealing with this topic, search for sites dealing with the ‘dead zone’
the use of this organism may provide a method for farmers to retain high agricultural productivity while still meeting new regulations likely to be imposed.
View attachment 2116362
(Enhanced root development from field-grown corn and soybean plants as a consequence of root colonization by the rhizosphere competent strain T. harzianum T22. Enhanced root development probably is caused by a combination of several of the mechanisms noted above.)
General References:
There are a number of references that provide a wealth of information about these fungi. Some of these are listed below.
Books:
Kubicek, C. P. and Harman, G. E. 1998. Trichoderma and Gliocladium. Vol. 1. Basic Biology, Taxonomy and Genetics, Taylor & Francis, London. 278 pg.
Harman, G. E. and Kubicek, C. P. 1998. Trichoderma and Gliocladium, Vol. 2, Enzymes, Biological Control and Commercial Applications. Taylor & Francis, London. 393 pg.
Chet. I. 1987. Innovative Approaches to Plant Disease Control. Wiley-Interscience, New York, 372 pg.
Lumsden, R. D. and Vaughn, J. L. 1993. Pest Management: Biologically Based Technologies. Am. Chem. Soc., 435 pg.
Chet, I. 1993. Biotechnology in Plant Disease Control. Wiley-Liss, New York, 373 pg
Published Papers:
Altomare, C., Norvell, W. A., Björkman, T., and Harman, G. E. 1999. Solubilization of phosphates and micronutrients by the plant-growth promoting and biocontrol fungus Trichoderma harzianum Rifai 1295-22. Appl. Env. Microbiol. 65:2926-2933.
Elad, Y., and Kapat, A. 1999. The role of Trichoderma harzianum protease in the biocontrol of Botrytis cinerea. Eur. J. Plant Pathol. 105:177-189.
Copywright and Publication Rights Held by Cornell University.
^ Written by cornell, compiled by me.
do you have any questions? be free to ask
Trichoderma spp. are fungi that are present in nearly all soils and other diverse habitats. In soil, they frequently are the most prevalent culturable fungi. They are favored by the presence of high levels of plant roots, which they colonize readily. Some strains are highly rhizosphere competent, i.e., able to colonize and grow on roots as they develop. The most strongly rhizosphere competent strains can be added to soil or seeds by any method. Once they come into contact with roots, they colonize the root surface or cortex.
View attachment 2116314
(Fig. 1: Cultures of Trichoderma harzianum strain T-22 (KRL-AG2) growing on potato dextrose agar. The white areas do not contain spores, while the green areas are covered with dense masses of spores (conidia).)
In addition: Trichoderma attack, parasitize and otherwise gain nutrition from other fungi. Since Trichoderma grow and proliferate best when there are abundant healthy roots, they have evolved numerous mechanisms for both attack of other fungi and for enhancing plant and root growth.
Pathogens controlled: So far as the author is aware, different strains of Trichoderma control every pathogenic fungus for which control has been sought. However, most Trichoderma strains are more efficient for control of some pathogens than others, and may be largely ineffective against some fungi. The recent discovery in several labs that some strains induce plants to "turn on" their native defense mechanisms offers the likelihood that these strains also will control pathogens other than fungi.
Pesticide susceptibility: Trichoderma possess innate resistance to most agricultural chemicals, including fungicides, although individual strains differ in their resistance. Some lines have been selected or modified to be resistant to specific agricultural chemicals. Most manufacturers of Trichoderma strains for biological control have extensive lists of susceptibilities or resistance to a range of pesticides.
Plant growth promotion: For many years, the ability of these fungi to increase the rate of plant growth and development, including, especially, their ability to cause the production of more robust roots has been known. The mechanisms for these abilities are only just now becoming known.
Some of these abilities are likely to be quite profound. Recently, we have found that one strain increases the numbers of even deep roots (at as much as a meter below the soil surface). These deep roots cause crops, such as corn, and ornamental plants, such as turfgrass, to become more resistant to drought.
Perhaps even more importantly, our recent research indicates that corn whose roots are colonized by Trichoderma strain T-22 require about 40% less nitrogen fertilizer than corn whose roots lack the fungus. Since nitrogen fertilizer use is likely to be curtailed by federal mandate to minimize damage to estuaries and other oceanic environment (there are a number of other sites on the web dealing with this topic, search for sites dealing with the ‘dead zone’
the use of this organism may provide a method for farmers to retain high agricultural productivity while still meeting new regulations likely to be imposed.View attachment 2116362
(Enhanced root development from field-grown corn and soybean plants as a consequence of root colonization by the rhizosphere competent strain T. harzianum T22. Enhanced root development probably is caused by a combination of several of the mechanisms noted above.)
General References:
There are a number of references that provide a wealth of information about these fungi. Some of these are listed below.
Books:
Kubicek, C. P. and Harman, G. E. 1998. Trichoderma and Gliocladium. Vol. 1. Basic Biology, Taxonomy and Genetics, Taylor & Francis, London. 278 pg.
Harman, G. E. and Kubicek, C. P. 1998. Trichoderma and Gliocladium, Vol. 2, Enzymes, Biological Control and Commercial Applications. Taylor & Francis, London. 393 pg.
Chet. I. 1987. Innovative Approaches to Plant Disease Control. Wiley-Interscience, New York, 372 pg.
Lumsden, R. D. and Vaughn, J. L. 1993. Pest Management: Biologically Based Technologies. Am. Chem. Soc., 435 pg.
Chet, I. 1993. Biotechnology in Plant Disease Control. Wiley-Liss, New York, 373 pg
Published Papers:
Altomare, C., Norvell, W. A., Björkman, T., and Harman, G. E. 1999. Solubilization of phosphates and micronutrients by the plant-growth promoting and biocontrol fungus Trichoderma harzianum Rifai 1295-22. Appl. Env. Microbiol. 65:2926-2933.
Elad, Y., and Kapat, A. 1999. The role of Trichoderma harzianum protease in the biocontrol of Botrytis cinerea. Eur. J. Plant Pathol. 105:177-189.
Copywright and Publication Rights Held by Cornell University.
^ Written by cornell, compiled by me.
do you have any questions? be free to ask
