F.M.L. Sheffield
Recent rapid expasion in horticulture, agriculture and forestry in East Africa has necessitated an increase in the importation from overseas of clones and cultivars of economic plants, both for local trial and selection and for breeding purposes. None of these importations is completely devoid of the risk that new pests and pathogens will be imported with them. It is therefore necessary to weigh these risks against the potential value of the imported material. This is particularly important in East Africa where importations were rare prior to the promulgation of importation regulations and, as a consequence, the countries of East Africa are relatively free from the more damaging pests and pathogens.

It may be necessary to take precautions to protect:

  1. Existing fields or plantations of established crops. For example, Citrus spp. carry many viruses but, so far as is known, these will affect only closely related genera.
  2. Other crops. Many ornamentals that are of little economic importance in East Africa can carry viruses such as 'Tomato Spotted Wilt' and 'Aster Yellows' which can cause severe infection in many important crop plants; several ornamental plants are alternate hosts of pine rusts and certain trees must be restricted for the protection of cocoa.
  3. Both the imported and other species. Pineapples can carry 'Tomato Spotted Wilt' and grape-vines could be infected with a virus capable of infecting legumes and other host plants. Apart from various fungal, bacterial and nematode diseases, the Irish potato is known to be susceptible to 46 viruses, many of which have wide host ranges among horticultural crops.
Sheffield, F.M.L. (1971). SECTION G - PLANT PROTECTION - THE CONTROL OF PLANT IMPORTATION. Acta Hortic. 21, 183-185
DOI: 10.17660/ActaHortic.1971.21.30

Acta Horticulturae