Studies on Pathogenicity of Potato cyst Nematode, Globodera rostochiensis and G. pallida on Potato

The pot culture experiments were conducted under polyhouse condition to study the pathogenicity of potato cyst nematode, Globodera rostochiensis and G. pallida on potato cv. Kufri Jyoti at different inoculum levels of 0, 10, 100, 1000 and 10,000 J2 per plant. The results revealed that, the potato cyst nematode Index was 4.0 at inoculum level of 10,000 J2/plant and 1.75 at 10 J2 per plant. However, the reproduction factor was highest 215.61 with the lowest inoculum level of 10 J2/ plant where as 118.42, 47.71 and 22.02 respectively with the initial inoculum levels of 100, 1000 and 10,000 J2 / plant. A gradual increase in the nematode inoculum levels declined the plant growth parameters progressively from 100 to 10,000 second stage juveniles (J2) per plant. The highest reduction in plant growth was recorded at a level of 10,000 J2/plant and the minimum was recorded at a level of 100J2/plant, where as 1000 J2/plant recorded as an Economic Threshold Level. Inoculation of 1000 J2/plant showed 40.60, 32.00, 40.07 and 70.20 per cent reduction in plant height, fresh weight, dry weight and yield per plant compared to uninoculated control. The maximum of 87.35 % yield reduction was recorded, at an inoculum level of 10,000 J2/plant followed by 70.20 and 27.00 % at a levels of 1000 and 100 J2/plant respectively.