Vertical and Horizontal Distribution of Virus-Vector Nematodes and Implications for Sampling Procedures

The vertical distribution of virus-vector nematodes was investigated in 37 fields in Eastern Scotland. Longidorus elongatus was most abundant in the top 10 cm while populations of Xiphinema diversicaudatum and of trichodorid nematodes were more numerous at greater depths. The horizontal distribution of the nematodes was studied in eleven fields using Taylor's Power Law. L. elongatus was found to have a less aggregated distribution than trichodorid nematodes. The knowledge gained of the spatial distribution of the nematodes was used to investigate the effectiveness of different sampling strategies. Taylor's Power Law index of aggregation was used to produce optimum transformation constants for the nematodes.