An improved procedure for assaying hatching activity of potato root diffusates towards globodera rostochiensis

A bioassay for cyst nematode hatching activity is described which is applicable to purification research on hatching factors. Using an easily-constructed incubation unit, based on a 96-well microtitre plate, cysts were suspended, via ″ thimbles″ of wire mesh, in test samples. The use of size-graded cyst samples reduced inter-replicate variability with respect to total egg content and hatching rate. The optimised bioassay procedure used 340 μl test volumes and replicate sizes of five cysts, and the cumulative number of juveniles hatching per cyst after 5 days was closely positively correlated with final hatch (after 31 days). This procedure significantly reduces the labour, time and space requirements of hatching bioassay.