The Influence of Temperature On the Ability of Aphelenchoides Besseyi To Survive Dehydration

Abstract

Experiments with rice (Oryza sativa var. Taipei 309) florets and grains at the milk stage showed that, compared to the treatments at 20°-30° C, dehydrations at temperatures below 15° significantly reduced survival of the infecting Aphelenchoides besseyi. No difference in nematode survival was detected between the higher temperatures tested. However, in the treatments between 15°-5°, ability of the nematode to survive desiccation was progressively reduced with decreasing temperature. Investigations with nematode aggregates revealed that only the initial stages of dehydration were sensitive to chilling. Once desiccated to a certain extent at room temperature, the nematodes appeared to be no longer sensitive to subsequent dehydration at low temperatures. Nematodes in the hydrated condition were insensitive to chilling. It is suggested that lipids in the nematodes' membranes undergo phase transition which if accompanied by desiccation becomes irreversible resulting in loss of subcellular compartmentation.