Survival of merlinius Brevidens under desert conditions

Many plant parasitic and free living nematodes undergo anhydrobiosis. Under laboratory condition Merlinius brevidens (Allen, 1955), could stay die only under low temperature and high moisture conditions. It survived desiccation provided it was dried gradually. Drying of nematodes in a drop of water at 80% R.H. and 25°C, on a glass slide did not provide sufficient time for nematodes to undergo revivable resistant stage. Evaporation of nematode suspension at 80% R.H. and 30°C, on a filter paper was again, not slow enough for nematodes to become tolerant to moisture stress. Sudden change of relative humidities from 95%, 80%, or 60% to 0% did not support survival. On the other hand adult and larval stages of Pratylenchus thornei could survive desiccation under natural conditions and revived back when naturally infested dy roots were soaked in water. Under extreme dry and hot weather condiions of deserts M. brevidence does not maintain its inoclum in sandy soil because of anhydrobiotic characteristic but because of resistant unhatched larvae inside the eggs.