title: Crop rotation effects on population densities of ectoparasitic nematodes.
abstract: The influence of rotation crop species on population densities of ectoparasitic nematode species common to soybean and corn fields of the North-Central region of the USA was studied for 5 years in 16 field blocks rotated to corn, soybeans, oats, wheat, and forage mixtures. Each block was sampled each year between mid-July and mid-August. High populations of Helicotylenchus pseudorobustus were maintained in all crops, especially corn. Tylenchorhynchus martini and Xiphinema americanum also developed with all crops, but a second year of corn depressed densities of both species. Paratylenchus projectus densities were high on soybeans and on forage consisting primarily of legumes.
authors.forename: V R
authors.initials: VR
authors.lastname: Ferris
authors.forename: R L
authors.initials: RL
authors.lastname: Bernard