The cumulative build-up of Pasteuria penetrans spores in field soil and pots over three crop cycles was investigated after re-incorporation of roots of cucumber and tomato plants infested with root-knot nematodes parasitised by P. penetrans. ln a pot experiment re-incorporation of tomato roots infected with root-knot nematodes parasitised by P. penetrans increased the spore population to a level at which nematode invasion was prevented. ln the field experiment, the second stage juveniles extracted from the soil after three crop cycles of cucumber had a mean number of eight spores attached. Neither spore attachment nor development of the parasite was affected if spores of P. penetrans were exposed to four commonly used fungicides.
Giannakou, I.O.; Gowen, S.R.; Melki, K.C.; Pembroke, B. The cumulative build-up of Pasteuria penetrans spores in root-knot nematode infested soil and the effect of soil applied fungicides on its infectivity. Fundamental and applied nematology (1998) 21 (6) 679-683.