Distribution and abundance of the cocoa shield bug, Bathycoelia thalassina (Hemiptera: Pentatomidae) in Ghana
Bathycoelia thalassina occurs in all cocoa growing regions of Ghana and in high numbers where the Amazon varieties and hybrid selections of cocoa are grown. Using different sampling methods, the maximum population of B. thalassina was estimated at about 5500 per ha between September and November. Its abundance followed the cocoa cropping seasons with increased numbers when young pods were available from late February to April and a decline when mature pods were harvested in June-July. In late August when more young pods are produced, the population again built up and reached a peak in October-November before collapsing in December-January at the end of the harvesting period. Ninety-nine per cent of B. thalassina nymphs and adults occurred on pods, fans and the trunk. If spraying is necessary to control this pest it should be done only on the trunk and the inside branches of trees where most pods are found. B. thalassina aggregated mainly along the ten rows at edge of the farm bordering bush. It occurred under cocoa with a continuous canopy providing light intensities between 500 and 2150 lux beneath the trees. Insecticide treatments should therefore be carried out only in these areas
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| Format: | biblioteca |
| Published: |
1977
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| Subjects: | THEOBROMA CACAO, BATHYCOELIA THALASSINA, DISTRIBUCION NATURAL, EVOLUCION DE LA POBLACION, MUESTREO, METODOS, GHANA, |
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