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Environmentally and Worker Friendly and Low Cost Fumigation Methods for Fumigating Tea Nurseries
By Admin | July 1, 2009
Nurseries are focal points of spread of soil born pathogens such as fungi, bacteria, nematodes and weed seeds to hitherto uninfested areas which will cause future economic damage in agricultural crops. Hence, sterilization of nursery soils and nursery premises are of paramount importance.
Chemical treatment of soil is the most effective means of eradicating these pests. Amongst, agrochemicals, the fumigants are hazardous chemical groups known to cause biological and environmental degradation and worker and animal health.
We fine tuned the methodology of the existing tea nursery fumigation recommendation with Basamid and Metham Sodium in view of assuring reduced non-target effects. The rates of application were brought to half through strengthening the methodology.
The new method resulted in comparatively lower effects on the soil microbial activity and no phytotoxic effects on the plating materials proven through seed germination. The release of the chemical compounds to the environment was minimized and thus reducing the worker and animal exposure. Moreover, the time period for fumigation process was brought from 42 days to 22 days which results in savings on cost, labor and space. Record keeping, displaying sign boards and fumigation schedule were made compulsory.
Although the soil fumigants do not leave any residues in the final food produce, we imposed a Restricted Entry Interval (REI) of 8 days in view of worker and animal safety. The current recommendation is highly beneficial for the small holder and cooperate sector tea growers who practice large scale nurseries. Also, the new certification systems such as Global GAP, Forest Garden Alliance, Natural, Fair trade, ISO, Organic and Biodynamic etc. requesting worker, environment and product safety will be aided tremendously by this the new fumigation methodology.
The method developed for tea could be well adopted in other agricultural nurseries for more benefits.
Keerthi Mohotti, Nissanka Navaratne, D. D. Liyanage, Deepthi Amarasena, Ajith Prematunga, U. B. Herath, G. P. Udamulla and P. K. Jayawickrema
Entomology and Nematology Division, Tea Research Institute, Talawakele, Sri Lanka
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