Soil fumigation is the most drastic measure that growers can perform and is often a method of last resort. Fumigants are general biocides; they are effective against fungi, bacteria, nematodes, soil insects, and weed seeds. They have several serious drawbacks:
- Fumigants kill all organisms, even the beneficial ones that compete with or parasitize plant pathogens. They leave a biological vacuum which can be quickly reinfested with serious plant pathogens.
- Fumigants have a high acute inhalation toxicity and are carcinogenic. They represent a hazard to humans, wildlife, and the environment.
- Fumigants require specialized equipment and procedures to apply properly. They are usually applied by professional crop production services. Soil preparation, temperature, and rate of chemical will determine how effectively pests will be controlled.
Fall is the best time to fumigate. However, it can be very effective in spring with an appropriate post-treatment waiting period. Careful attention should be paid to soil temperature and moisture, as well as time of exposure as indicated on the product label. Plowing below the depth of treatment will mix non-treated and treated soil.
Read the label carefully before using fumigants and see the guidelines listed under Fumigants for Greenhouse Bench and Small Batches.
dichloropropene plus chloropicrin (Telone C-17) or dichloro-propene (Telone II): 5.0-40 gal/A. Controls certain soil insects, nematodes, and soil-borne fungi. Read and follow the instructions on the label carefully.
dichloropropene plus chloropicrin (InLine): 13.0-20.5 gal/A. Controls certain soil insects, nematodes, and soil-borne fungi. Read and follow the instructions on the label carefully.
sodium methyl dithiocarbamate (Vapam HL): 50.0-100.0 gal/A. Controls weeds, soil insects, nematodes and soil-borne fungi. Read and follow the instructions on the label carefully.