Distribution of Heterodera carotae and Meloidogyne hapla in Michigan Carrot Production.

During 1986 and 1988, selected farms in all of the major carrot-growing counties of Michigan were surveyed to determine the extent of infestation by Heterodera carotae and Meloidogyne hapla. Both species were found in all eight counties surveyed, but not on all farms. Heterodera carotae was recovered from 67.4% of the fields surveyed. Meloidogyne hapla was detected in 24.8% of the samples and from 69.8% of the fields. In most cases, H. carotae and M. hapla occurred in the same field.