The Forest Resource of Ghana and Research on Hypsipyla robusta (Moore) (Lepidoptera: Pyralidae) Control in Mahogany Plantations in Ghana

摘要

The forestry sector is a major contributor to the national economy of Ghana, employing some 75 000 people and contributing between 6percent and 8percent of the Gross Domestic Product. Over-exploitation of the timber resource, particularly from the unreserved forests, has led to severe depletion of the highly desirable, traditional mainstays of the Ghanaian timber trade such as Pericopsis elata (Harms) van Meeuwan ('Aformosia'), Milicia spp. ('Odum' or 'Iroko') and the Meliaceae. Previous management policy promoted the sustained supply of forest produce for the timber industry. There are currently 50 000 ha of plantations in Ghana, of which nearly 90percent are exotic species, mainly Tectona granis L., Cedrela odorata L. and Gmelina arborea Roxb. Attempts by the Forestry Department to establish indigenous tree species in open plantations have failed for several reasons, including poor tending operations, poor seed sources, fire, and pests and diseases. Overall success rates in all plantations were poor, ranging from 20-58percent, but were particularly so among native Meliaceae, of which only 9percent survived, largely as a result of damage by the shoot borer Hypsipyla robusta (Moore). With a projected increase in demand for wood and increasing interest in plantation development among individuals and private companies, there is an urgent need for an effective method of control of H. robusta. This paper outlines past and current research on H. robusta in Ghana, and discusses future research strategies that could help to reduce shoot borer impact on plantations of native Meliaceae in Ghana and the rest of West Africa.