Gas dispersion of cyanide fumigation in the sheet covered on the tea bushes was tested with calcid duster or pot method.
1. The best result was obtained when two rows of bushes were covered with a double vinyl sheet(white and black)and the insecticide was scattered by a duster from either end between the rows.
2. The pot method proved that the gas dispersion, decreasing rate of gas density were better than the duster fumigation but the operation was somewhat troublesome.