KINETICS OF RECOVERY FROM ANHYDROBIOSIS IN PRATYLENCHUS-THORNEI, MERLINIUS-BREVIDENS AND HETERODERA-AVENAE FROM DRY FIELD SOILS AND DRY ROOTS OF THE HOST-PLANT

The behaviour of Pratylenchus thornei, Merlinius brevidens and Heterod era avenae in a distinctively dry soil environment of Southern Spain h as been studied after the summer season. Six times of recovery, up to 135 hours of rehydration plus migration, let to recover more than 95% of the Merlinius population. But for Pratylenchus, which seems to be t he predominant and most important nematode species there, after a whea t var. yecora, a quantitative recovery of 95% or more of its true popu lation density is only reached after twelve times, 279 hours, as far a s all the remaining wheat roots are considered and processed. Those Pr atylenchus that survive within dry wheat roots seem to be the cause of some until now unexplained losses of wheat yield. Heterodera avenae s eems to play a secondary role in this dry soil environment.