Influence of root-knot nematodes on yield of tobacco in northern New South Wales

Abstract

Root-knot nematode galling and yield of tobacco were measured in six nematicide trials in northern New South Wales. There were significant differences in the average galling indices of treatments in all trials. Treatment yields differed significantly in only one trial. Straight-line regression analyses of plot yield on plot galling index showed a significant correlation in four trials. These analyses indicate yield losses of 2.6-9.4% for increments of 10 in galling index. [Index = 1.25 X (sum of gall scores for 20 plants), where scores range from 0 (no galls) to 4 (75- 100% of root galled).]