The ability of second-stage juveniles of Meloidogyne chitwoodi and M. Fallax to survive desiccation and osmotic stress
2010
Aslam, M. (Islamia Coll. Univ., Peshawar (Pakistan))
The effect of different relative humidities and osmotic stress on the survival of Meloidogyne chitwoodi and M. fallax second-stage juveniles (J2) was examined. Experiments were carried out at 25 degree C. J2 of M. chitwoodi and M. fallax could not survive desiccation when exposed to low relative humidities (RH) of 33 %, 59 % and 76 %. However, survival of individuals of both species was high at 98 % RH. Survival of M. chitwoodi J2 was better than J2 of M. fallax. J2 of both species were able to survive low relative humidities for periods of only 5 min. In order to assess the effect of osmotic stress on the J2 of M. chitwoodi and M. fallax, five solutions of different osmotic pressures were used for experiments. The results indicated that survival of J2 of both M. chitwoodi and M. fallax was minimum at high osmotic pressure of 807 mOsm / kg. After exposure to the different osmotic pressures the revival of J2 of both these species was minimal af ter exposure to high osmotic pressure of 807 mOsm / kg compared with revival from lower osmotic stresses, which means that J2 of M. chitwoodi and M. fallax either were killed or were moribund due to high osmotic stress.
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