178 * Technologies To Maintain Biological Diversity 



Table 7-1.— Crops and Trees Commonly Prohibited Entry by Quarantine Regulations in 125 Countries 



Percentages of 



Number of countries Percentages of countries countries prohibiting: 



in wfiich crops/genera that name one or more Plants Plants Seeds 



Crops and trees are prohibited pests or pathogens only^ and seeds only 



Forest crops: 



Maple 14 43 100 



Chestnut 34 23 76 24 



Conifers'' 27 26 100 



Hawthorn 14 86 100 



Walnut 21 48 100 



Poplar 27 44 93 7 



Oak 25 47 92 8 



Willow 22 45 100 



Ash 24 58 96 4 



Elm 32 47 94 16 



Fruit crops: 



Citrus 62 45 55 45 



Coconut 28 32 29 64 7 



Strawberry 20 55 65 35 



Banana 39 39 54 46 



Pome fruits'^ 37 68 85 15 



Prunus (cherry, plum, etc.) 37 68 85 15 



Currant 16 38 69 31 



Grapevine 41 41 90 10 



Vegetable crops: 



Sweet potato 23 35 61 39 



Potato 41 41 90 10 



Other crops: 



Coffee 49 31 24 57 18 



Cotton 52 23 25 61 14 



Sunflower 15 40 20 80 



Rubber 28 50 29 71 



Tobacco 26 31 35 58 7 



Oil palm 16 38 56 44 



Rice 33 42 21 61 18 



Rose 22 41 100 



Cacao 43 42 19 79 2 



Tea 20 45 45 55 



Sugarcane 40 10 63 37 



^Includes plants as well as any parts for vegetative propagation. 

 '^Specifically, ttie genera PIcea, Larix. Pinus. and Abies. 

 ^-Includes tfie genera Chaenomeles. Cydonia. Malus. and Pyrus. 



SOURCE; R,P. Kafin, "Technologies To Maintain Biological Diversity: Assessment of Plant Quarantine Practices." OTA commissioned paper, 1985. 



tibodies to pathogens provide rapid results but 

 may not detect all forms of a particular patho- 

 gen (60). Molecular techniques to detect the 

 genetic material of pathogens are available, but 

 these may require better-equipped laboratories 

 and greater expertise than is available in many 

 quarantine programs. Identifying the presence 

 of a pathogen can thus be difficult because a 



negative result may be due to inadequate tech- 

 nology. It is essential, therefore, that the limits 

 of any technology be understood. Basic re- 

 search on the biology of pathogenic organisms 

 and the technologies used to detect them is 

 needed to improve testing procedures, develop 

 them for other pests and pathogens, and un- 

 derstand the limits. 



STORING SAMPLES 



Storage technologies aim to preserve an ade- 

 quate amount of plant germplasm, sustain its 

 viability, and preserve its original genetic con- 



stitution (81). Plants can be maintained offsite 

 in a number of forms and w^ith a number of tech- 

 nologies (table 7-3). They may be maintained 



