Hatching activity, invasion rate and reproduction of Heterodera schachtii on oilseed rape cultivars
AbstractEffects of root diffusates of oilseed rape cultivars, Cobra, Global, K16 and Tower on hatching activity, rate of invasion and reproduction 0/ Heterodera schachtii were determined. Root leachates were obtained by drenching 50 day old plants with 500 ml distilled water, 5 ml of which was added to Petri dishes containing 50 cysts and kept at 20 °C for four weeks. Rate of penetration of H.schachtii was determined by inoculating 40 day old seedlings with 1200 juveniles and roots were examined at three days intervals. To measure the susceptibility of cultivars, 40 day old plants were inoculated with ca. 3400 juveniles of H. schachtii and harvested after two months in the glasshouse. Nematodes hatched in root leachates were 24.5, 17.4, 9 and 8% for Cobra,Global, K16 and Tower respectively. Beet cyst nematodes penetrated the roots of all rape cvs, invasion rate being 18% for K16, 15% for Tower, 13% for Global and 12% for Cobra. Adult females were produced on the roots of all cvs, with K16 being the most susceptible compared with the others.