Control of Damping-off of Tobacco in Seedbeds by the Use of Gaseous Soil Fumigants

Abstract

The gaseous soil fumigants, methyl bromide and chloropicrin aerosol, have the following advantages for tobacco seedbeds: 1. They are more effective in the control of damping-off in Puerto Rico than fungicides previously recommended. 2. Their herbicidal properties eliminate the need for handweeding, an expensive and time-consuming operation. 3. Only one application is needed, and this is made before seeding the tobacco, thus eliminating the critical timing required for fungicide application. The emergence of seedlings was higher in beds treated with the soil fumigant. This increased emergence probably occurred because pre-emergence damping-off was controlled, and no hand-weeding was necessary, so that no seedlings were destroyed in the process of hand-weeding. The expense of the soil-fumigation method is greater than that of the fungicide drench. In addition to the fumigant it is necessary to purchase an applicator and gasproof covers. However, the gaseous soil-fumigation treatment eliminates the need for hand-weeding and gives better control of damping-off. Therefore the soil-fumigation method could be economically feasible.