THE EFFECTS OF MOISTURE ON THE THERMOSENSITIVITY OF GLOBODERA-ROSTOCHIENSIS (NEMATODA)

The sensitivity of Globodera rostochiensis second-stage juveniles in eggs inside cysts (encysted J2) to heat was evaluated over a range of temperature and moisture levels. Encysted J2 in air dried cysts incubated in dry sand were less sensitive to thermal stress than those maintained under moist conditions. Heating of moist cysts to 50°C for 20 minutes in wet sand resulted in death of the encysted J2. Presoaking air dried cysts for 48 hours in water prior to heating in dry sand did not increase the sensitivity of encysted J2 to heat. Thermal sensitivity of encysted J2 presoaked for 48 hours in water or glycerine and then heated to 51°C or 56°C indicated that both water and glycerine conducted heat to the J2. Hydrated (water soaked) encysted J2 were killed at lower temperatures and at shorter exposures than were anhydrobiotic (glycerine soaked) encysted J2. Presoaking cysts in potato root diffusate to initate hatching did not increase the thermal sensitivity of encysted J2. © 1990 Springer.