Field resistance to nonfumigant nematicides in Xiphinema index and Meloidogyne incognita

Abstract

Populations of Xiphinema index and Mebidogyne incognita were sampled from three vineyard plots. Two had been treated with either carbofuran or phenamiphos. The third was an untreated control. In the fourth year al1 three plots were treated with carbofuran. Assessments in the first year of treatment indicated that carbofuran applications had reduced the X. index population to one, half of the control levels. In the fourth year, however, the X. index population levels from the carbofuran and phenamiphos-treated vines were significantly higher than numbers taken from the control plot. Nematode numbers from the carbofuran-treated vines were more than three times the levels from the control plot. In vitro bioassays indicated that nematodes from the carbofuran and phenamiphos-treated plots had a higher tolerance to nonfumigant nematicides.