ARET, Annual Report 2001, p. 134-7.

Screening new chemicals for their efficacy on soil sterilization in tobacco seedbeds

ARET, Agricultural Research and Extension Trust, Lilongwe, Malawi
The effect of Methyl Bromide, Basamid (Dazomet), Telone II and Methan Sodium on nematodes and weeds in tobacco seedbeds is not known in Malawi although preliminary tests at Kandiya showed that Telone II was effective against nematodes and Methan Sodium was found effective against nematodes in Zimbabwe. The objective of this experiment was therefore to test sodium and Tellone II on the control of root-knot nematodes and weeds and other soilborne pests in tobacco seedbeds. The treatments were effected as follows: The land was cultivated to a tilth suitable for sowing and soil was watered for two weeks to field capacity to activate pathogens and weed seeds to grow in all the chemical treated beds except Methyl Bromide and the burning treatments in which watering was delayed by another two days. Two weeks later the soils on the seedbeds were loosened and Methan Sodium, Telone II, Basamid and Methyl Bromide were applied. Except for Telone II, the seedbeds treated with the other chemicals were covered with plastic sheets. Seven days later, plastic sheets were removed in the Methan Sodium and Basamid treated seedbeds and the soils were loosened again to release the gases an operation which was repeated three days later and then another three days the beds were left free before seeding was done. The results from this experiment showed that if proper procedures are followed in applying the chemicals, germination is not affected as shown by the seedling density. Basamid is a good alternative if not a replacement to Methyl Bromide because it was effective in reducing nematode population and weeds. Telone II only controlled nematodes and not weeds.