Phytophthora palmivora in cocoa plantation soils in the Solomon Islands
The most efficient of several soil-baiting methods for the detection of Phytophthora palmivora in soil proved to be the incubation of plugs of cocoa-pod tissue half-submerged in flooded soil in open Petri dishes. Negative dishes often gave positive results on a second baiting. In open-topped vials or in covered Petri dishes Pythium vexans frequently overran and obscured the presence of P. palmivora. Soil populations of P. palmivora scarcely diminished with increasing distance from the trunks of the cocoa trees and direct microscopic observation of propagules inoculated into soil in the field or in Petri dishes, suggested that propagules remain dormant in the soil under the influence of fungistasis. No P. palmivora was detected in soil from a disease free young plantation about to mature its first crop but in a plantation with a long history of black pod disease, P. palmivora was detected in over half the soil samples tested 2 months after felling. Populations persisted at low levels for 34 months. Fallen cocoa leaves were shown to be a potential source of splash-dispersed inoculum as were the fallen leaflets of the shade tree Leucaena leucocephala. Phytophthora palmivora was also isolated readily from "tents" of the ant Technomyrmex detorquens on cocoa pods
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| Format: | biblioteca |
| Published: |
1977
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| Subjects: | THEOBROMA CACAO, PHYTOPHTHORA PALMIVORA, ENFERMEDADES FUNGOSAS, SUELOS DE CACAO, EVOLUCION DE LA POBLACION, PROPAGULOS, INOCULACION, PLANTAS DE SOMBRA, LEUCAENA LEUCOCEPHALA, AISLAMIENTOS, ISLAS SALOMON, |
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