Articles
CHEMICAL ALTERNATIVES TO METHYL BROMIDE FOR SEEDBED FUMIGATION
Article number
635_21
Pages
165 – 173
Language
English
Abstract
For many years methyl bromide fumigation has been the standard treatment used for control of nematodes, weeds and soil-borne diseases in tobacco seedbeds.
However, its proposed withdrawal has necessitated the need to find alternative chemicals to replace it, and a number of possible replacements of methyl bromide have been tested over the past four years at the Tobacco Research Board.
The standard seedbed recommendation of 50 g/m2 of methyl bromide was compared with the alternative treatments of 65% 1,3-dichloropropene (1,3-D) plus 35% chloropicrin and combinations of metham sodium and ethylene dibromide (EDB). 1,3-D and chloropicrin are old chemicals, which have been tested and used in Zimbabwe as soil fumigants for many years.
However, the mixture of these two chemicals had not been tested for its efficacy in nematode and weed control, and its effect on tobacco seed germination and seedling growth.
Investigations on metham sodium were suspended in the late 1980s, because methyl bromide was readily available and provided good and cost effective control of nematodes, weeds and soil-borne diseases.
However it has become necessary to revisit work on this chemical.
Metham sodium at 35 ml/m2 gave adequate weed control and good tobacco seed germination and seedling growth.
Although nematode pressure was low in the experimental site, metham sodium applied on its own was not able to provide adequate control of root knot nematodes.
When 35 ml/m2 metham sodium was combined with 21 ml/m2 of EDB, nematode control comparable to that obtained with methyl bromide was achieved.
A combination of 1,3-D with 35% chloropicrin applied at the rate of 35 ml/m2 of the mixture provided good weed control and improved tobacco germination and growth.
All treatments gave control of root knot nematodes comparable to that obtained with the standard methyl bromide treatment.
However, its proposed withdrawal has necessitated the need to find alternative chemicals to replace it, and a number of possible replacements of methyl bromide have been tested over the past four years at the Tobacco Research Board.
The standard seedbed recommendation of 50 g/m2 of methyl bromide was compared with the alternative treatments of 65% 1,3-dichloropropene (1,3-D) plus 35% chloropicrin and combinations of metham sodium and ethylene dibromide (EDB). 1,3-D and chloropicrin are old chemicals, which have been tested and used in Zimbabwe as soil fumigants for many years.
However, the mixture of these two chemicals had not been tested for its efficacy in nematode and weed control, and its effect on tobacco seed germination and seedling growth.
Investigations on metham sodium were suspended in the late 1980s, because methyl bromide was readily available and provided good and cost effective control of nematodes, weeds and soil-borne diseases.
However it has become necessary to revisit work on this chemical.
Metham sodium at 35 ml/m2 gave adequate weed control and good tobacco seed germination and seedling growth.
Although nematode pressure was low in the experimental site, metham sodium applied on its own was not able to provide adequate control of root knot nematodes.
When 35 ml/m2 metham sodium was combined with 21 ml/m2 of EDB, nematode control comparable to that obtained with methyl bromide was achieved.
A combination of 1,3-D with 35% chloropicrin applied at the rate of 35 ml/m2 of the mixture provided good weed control and improved tobacco germination and growth.
All treatments gave control of root knot nematodes comparable to that obtained with the standard methyl bromide treatment.
Authors
Z. Sibanda, J. Way
Keywords
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