Tuesday, September 09, 2008 Colting: Biofumigation gaining world acceptance By Dr. Rogelio Colting Research for Development (R4D) Corner
(Jennyline S. Tabangcura and Grace T. Bengwayan guest write today's R4D Corner)
THE phasing out of methyl bromide for soil fumigation under the Montreal Protocol indicates to the world that pesticides that damage the environment will no longer be tolerated.
According to Wikipedia, the Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer. It has focused on the cause of ozone depletion, thus it has mandated the phasing out of substances believed to be responsible for ozone depletion.
The treaty or agreement has been adopted the world over. Former UN Secretary General Koffi Atta Annan said it is "perhaps the single most successful international agreement to date." The treaty has been revised seven times, until its final version in 1999.
Methyl bromide (CH3Br), on the other hand, is a colorless, poisonous gas used as solvent, refrigerant and fumigant. It is a recognized ozone-depleting chemical.
The soil fumigation is a practice of freeing the soil of bad microorganisms. It is done to reduce the incidence of diseases. Chemicals like methyl bromide are usually used for this purpose. Scientists have looked into bio-fumigation as a possible alternative.
To this effect, international conferences on bio-fumigation have been held. One is the third International Bio-fumigation Symposium in Csiro Discovery Centre, Canberra, Australia last July. This was attended by Dr. Luciana Villanueva, faculty member of the College of Agriculture and director of the Semi-Temperate Vegetable Research and Development Center (STVRDC).
The Center was established through the Vlaamse Inter Universitaine Raad (VLIR) Philippine Institutional University Cooperation Programme (PIUC).
According to Dr. Villanueva, bio-fumigation is the use of bioactive brassicaceous plant products for pests, disease and weed control.
An example of brassicas being used as soil fumigant is mustard. The phenomenon has been recognized for centuries, but has gained increasing interest in recent years due to the phase-out of synthetic soil fumigants and a general interest in more environmentally conscious plant production systems worldwide.
The concept is upon capturing benefits from the bioactive products of the glucosinolate-myrosinase system in plants which originally evolved as part of the plant's own defense system.
Dr. Villanueva presented her paper co-authored by Ms. Nordalyn Pedroche titled: "Organic amendments and host resistance as components of integrated disease management strategy for root knot nematode, Meloidogyne incognita in lettuce." The symposium aimed to showcase and exchange ideas from around the world on fundamental research in aspects of bio-fumigation.
She said majority of the papers presented showed that many bio-fumigant products suppress nematodes more effectively than fungal pathogens and obligate pathogens more so than facultative pathogens, which can utilize organic matter as food source.
Bio-fumigation could be another method of shifting into organic agriculture. It needs to be considered as a broader concept, which accounts for all the physical, chemical and biological changes that occur in the soil to achieve crop production and improve soil health.
