EFFICIENCY INCREASE OF METHYL BROMIDE SOIL FUMIGATION BY ADMIXTURE WITH METHYL CHLORIDE OR AMELIORATED TARPS

Since methyl bromide became criticized, both for application hazards and residues of the compound itself and the generated bromide, real substitution of the product by another was not possible.
On this base it was desirable to promote the penetration and distribution of methyl bromide by using more gas tight tarps or by addition of other compounds.
Both of the possibilities should allow to reduce the total input of active material.

Experimental data include diffusion monitoring of methyl bromide in the presence of methyl chloride or under different plastic seals, and results of biological tests for diffusion and bromide residue analysis in crops grown on treated soil.

It was shown that the choice of a good plastic tarp is of primordial importance allowing lower application doses but residues in crops were as high as before.
The admixture of methyl chloride used under LDPE (low density polyethylene) allowed much lower methyl bromide doses.

Another positive effect of methyl chloride is the longer persistence of methyl bromide in the soil gas phase.
This results in a longer pesticidal action and a stronger volatilization of the methyl bromide after removal of the tarp.
Combination of gas tight tarps such as Waloplast Combi XX, with the addition of methyl chloride masks the effect of the admixed compound.
A much lower dose of methyl bromide is possible for successful disinfestation with a good plastic tarp, but bad overlapping, holes or tears may annul the efficiency.

II International Symposium on Soil Disinfestation

E. VAN WAMBEKE

https://doi.org/10.17660/ActaHortic.1984.152.13