Relationship of Yield and Pratylenchus spp. Population Densities in Superior and Russet Burbank Potato.

Number of Pratylenchus spp. (primarily P. penetrans) were recorded at planting in experimental potato plots over a 9-year period at one location on Prince Edward Island. Tuber yields of 'Superior' and 'Russet Burbank' potatoes in plots treated with aldicarb were compared with yields in adjacent untreated plots. There was a linear relationship between the number of root lesion nematodes at planting and tuber yield increases after treatment for Superior, but not for Russet Burbank (P < 0.05). When counts of root lesion nematodes were greater than 500/kg dry soil, however, the tuber yields of Russet Burbank increased in treated plots. Additional trials at other locations and the inclusion of other cultivars are needed to make numerical relationships of this type available to a nematode advisory service.