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Report on a series of research and development technologies for prevention and treatment of "tree cancer" brown root disease-2

Taiwan Forestry Research Institute, COA, Executive Yuan R.O.C.
Chuen-Hsu Fu (Researcher)
Tel:886-2-2303-9978 ext. 2654

Use the best formula and the most suitable application method of urea-lime mixture to control tree brown root disease

        The most commonly used and currently legally registered agent for the prevention and control of tree brown root disease is Dazomet. In Taiwan, Dazomet is a fumigant that is legally registered, and can be used for tree brown root disease. However, some tree management units still have considerable doubts about pesticide residues and ecological impact. In addition, it is often unable for the imports of Dazomet to meet the demand. Based on the above two reasons, the Forest Research Institute has further studied, and found that urea-lime mixture can be used in combination to replace Dazomet for soil fumigation and disinfection, and good results have been obtained after repeated field tests.

        The use method and process of this technology are the same as those of Dazomet, except that Dazomet is replaced by a combination of urea lime for the convenience of use. The inspection and acceptance process required for prevention and control project is also the same, so its substitution of Dazomet is extremely high. At present, four companies have used this technology. For example, Taipei Zoo and some schools originally believe that the pesticide Dazomet might cause unexpected damage, and they are willing to use a urea lime formula to replace Dazomet to control tree brown root diseases. The acceptance or inspection marks of using this technology for the prevention work are the same as those of Dazomet, and the effect is also the same. With the gradual increase in the market sales price of Dazomet, plus the failure of Dazomet import volume to meet market demand, this technology has great potential for market development.


Treatment of endemic areas of tree brown root disease by flooding method


        Many science and technology are produced in response to user requirements. The most common and important tree disease in Taiwan is tree brown root disease. In order to effectively control the spread and infection of tree brown root disease, treatment of infected areas is necessary. At present, Dazomet is the most commonly used agent for prevention and treatment, and it is also currently recommended and legal registered. As many tree management units are unwilling to use pesticides or the import volume of Dazomet cannot meet the demand, the technology of “Using urea lime with the best formula and the most suitable application method to control the soil of tree brown root disease groups” was developed accordingly. However, the use of chemical urea is not allowed by some users of organic agriculture or natural farming methods or tree management units, then the flooding method is another prevention technology developed to meet the demand.

        In the early years, if tree brown root disease occurred in farmland, especially in areas where rice fields are converted to afforestation, farmers generally believe that it is uneconomical to use the subsidies for afforestation for the fumigation and disinfection of brown root disease. Hence, farmers would dig out the diseased roots of trees and burn them altogether before the paddy field farming mode was restored to avoid the occurrence of brown root disease. Some rural schools are also unable to fumigate and disinfect because of insufficient funds, and they have carried out another type of prevention and control work by converting the diseased areas to ecological ponds or wetland ecology areas after digging out the disease roots. However, some field trials and inspection steps are still needed to support this prevention method when it is really used in the brown root disease epidemic area where trees are still to be planted in the future.

        After conducting high-standard field tests, the Forestry Research Institute found that the effect of the flooding method is the same as that of the recommended agent Dazomet. In addition, in order to enable the control project to have an inspection and acceptance sequence, the adjustment of the acceptance and inspection procedures is also required for the control project to make the prevention and control project successful. At present, there is one operator that undertakes this technology. Although this technology is environmentally friendly, the operation technology is not problematic, and the cost is not high, the acceptance to its promotion does not seem to be high. In response to the current policy of pesticide reduction, the Forest Research Institute will continue to promote this technology to reduce the dependence on chemical substances.