DIFFERENTIAL HATCHING OF THE POTATO CYST NEMATODES GLOBODERA-ROSTOCHIENSIS AND GLOBODERA-PALLIDA IN ROOT DIFFUSATES AND WATER OF DIFFERING IONIC COMPOSITION

The hatching differences of Globodera rostochiensis and G. pallida were assessed in potato root diffusate (PRD) of cv . Bintje, cv. Elkana and clone ZB35-29. G. pallida hatched better in the PRDs than G. rostochiensis. It was shown that the experimental test conditions strongly influenced the hatching results. The water type used in the hatching tests had a significant discriminating effect on the species; G. rostochiensis reached hatch percentages of 60 to 90% in demineralized and tap water, whereas G. pallida never exceeded the 15%. These differences were independent of the various batches that were used or the different years the tests were carried out. Silver sand percolate had a inhibiting effect on the hatching of both nematode species. Boron and a high electrical conductivity may be responsible for this. The results are discussed from an ecological point of view as well as for research consequences.