Ecological studies on Pythium splendens braun in oil palm (Elaeis guineensis Jacq.) plantation soils

Summary The isolation of Pythium splendens Braun by a root-baiting technique showed that the infective propagules of the fungus were numerically 12 times as great in cultivated soil as in non-cultivated secondary forest soil.In cultivated oil palm nursery soil, the propagules of the fungus were found to be most abundant at a depth of between 15 and 30 cm below ground level. The recovery of the fungus from the soil around the roots of diseased oil palm seedlings was 4 times as great as that from around the roots of healthy seedlings. Farmyard manure increased the recovery of the fungus from naturally infested soil, whilst green manure reduced it.The recovery of the fungus from soil declined sharply with decrease in soil moisture content and also with the length of storage of air-dried soil.The recovery of the fungus from nursery soil was high in July–October and low in November–January and these variations corresponded with seasonal fluctuations in soil moisture content.