The exotic pests in the forest system of Eastern Africa: quarantine as a tool for excluding forestry pests in the region; a paper presented to the 9th meeting and scientific conference of the African association of the insect scientists.

Abstract

Many exotc species from temperate zones have been introduced to tropical highlands of Eastern Africa, owing to their relatively faster growth compared to the indigenous species. Although the bulk of industrial plantation crops are found in Kenya, currently, standing at about 165,000 ha of man made forests, the e~tire land mass stretching from Sudano - Sahelian belt to the heart of South Africa, (a distance of about 10,000 km) and from Eastern Zaire to Arabuko - Sokoke forests off the Indian Ocean on the East Coast of Kenya, ( a distance of 3,000 km), support large tracts of industrial plantations. With growing sophistication and affluence in external travel and trade, the danger of entry of alien organisms through commercial'. private. shipment of plant materials and travellers, has become a more pressing problem to forest managers in all parts of the world. Movement of vegetative material for propagation or seed which may be diseased or infested and clothing, soil, humus, peat, compost and lumber are important carriers of all stages and categories of plant enemies. Through movement of these materials, man has facilitated transcontinental spread of many pernicious pests and diseases. The dilemma between introducing beneficial foreign plants and the danger of introducing alien pernicious organisms has called for the introduction of quarantine systems and international co-operation phytosanitary services. The evolution of plant quarantine systems in East Africa is reviewed and the laws and phytosanitary regulations in Kenya are discussed. The paper summarises the major foreign pests found in Eastern and Southern Africa. While recognizing that foreign pests cannot be excluded fo ever, it is noted that delay of any duration in entry of any pernicious organism means that resources for con~rol are saved. In conclusion, the paper recommends: (a) the establishment of Eastern Africa Sub-Regional Plant Quarantine Services to promote uniform and common phytosanitary services for the countries of the region; (b) promotion of international co-operation on plant phytosanitary practices be supported by improved scientific liaison and information exchange on forest pests, their management, and the maintenance of constant surveillance of crops and phytosanitary inspection at points of exit and entry, to ensure valid phytosanitary guarantees and pedigree work of the exporting and receiving countries; (c) limiting exchange of plant material to seeds and budwood to be introduced through a quarantine station; (d) screening of materials carried by travellers, greater education of the travelling public and provision of cornprehensive appeals on the importance of providing honest declaration on imported plant materials etc.