The mean yield of field beans grown for three consecutive years on a site infested with migratory nematodes was 1540 kg grain/ha in untreated soil and 1870 kg/ha in soil treated with dazomet.
Fertilizer nitrogen in amounts up to 250 kg N/ha decreased yield to 990 kg in untreated soil but increased it to 2220 kg in soil treated with dazomet. Fertilizer nitrogen did not affect nematode numbers or root blackening but decreased nodulation and increased mycorrhizal infection by Endogone sp. in untreated soil. Dazomet greatly decreased migratory nematodes of the genera Tylenchorhynchus and Trichodorus and eliminated Pratylenchus. It had little effect on root blackening in the top 10 cm of soil but decreased it in the next 10 cm. Infection with Endogone was almost eliminated.