36 DISSEMINATION OF PARASITIC FUNGI 



exist, from infected areas to neighbouring districts, is largely independent of 

 nursery trade. Hence there is not the same inducement to keep nurseries only 

 engaged in internal tiade free from infection, as there is when dealing with 

 nurseries which trade with countries which the parasites can only reach if 

 carried with the host plant. Naturally it is (or ought to be) the interest of 

 every nursery not to sell diseased stock in the country, but it need not be 

 the same pre-occupation of Government to keep up the good name of a nursery 

 engaged in internal trade, as with an exporting nursery where the trade must 

 inevitably cease under the international regulations when the stock for export 

 becomes infected. An exception should be made with new diseases on their 

 first appearance. Any nursery found infected might well be quarantined in 

 such a case, and as it is often not in any way the fault of the nursery that it 

 becomes infected, the question of compensation would arise. But once the 

 disease has got a footing in several different parts of the country or has 

 extended widely in a particular district, it seems to me that the Govern- 

 ment service should concern itself chiefly with keeping exporting nurseries 

 free from infection. 



The control of transport and packing is probably less important (or perhaps 

 it would be better to say, its effect is less accurately known) in the case of 

 fungus diseases than with insect pests. In a general way there is relatively 

 little danger of a fungus parasite, in a reasonably well packed consignment, 

 escaping during transport. When it is present in the neighbourhood during 

 packing (not necessarily on the plants packed), there is probably a danger of 

 the packings becoming contaminated. Unfortunately there is little informa- 

 tion on this point, but it seems undoubtedly to be possible. When the con- 

 signment is unpacked, spores thus carried might sometimes get loose. Hence 

 it would be a wise precaution to pack and unpack away from gro\ving plants 

 or their debris, and preferably in sheds or other enclosed spaces, and also to 

 burn all used packings very carefully. 



The notification of disease can very easily be overdone, and there ought 

 to be less lather than more need for it as time goes on. This is because at 

 present many States require certificates stating that a particular disease does 

 not exist near the locality from which the plants have come, whereas for all 

 plants subject to the Convention nothing of the kind can well be demanded by 

 one adhering State fiom another. In the discussions during the meeting at 

 which the Convention was signed, it seems to have been generally recognised 

 that the certificates should be passports to free entry (provided naturally that 

 they are not found to have been -wTongly given), and it might be advisable 



