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favour of the supposition that we owe oar 4 green coffee bug ' (Lecan- 

 ium viride) to Western Africa. Aspidiotus cydonise, Chionaspis biclavis 

 and Mytilaspis citricola, were originally described from America. As- 

 pidiotus camelliae. A. cyanophylli, Chionaspis aspidistrae, and 

 Dactylopius citri, are all well known on the continent of Europe. 

 Aspidiotus aurantii and Pnlvineria psidii have their home in Australiasia. 

 Our former coffee pest, the 1 brown bug 1 (Lecanium coffeae) might per- 

 haps be quoted as an exception to this rule, as it was first recorded from 

 Ceylon. But this insect is now considered to be merely a local variety 

 of Lecanium hemisphaericum, an insect found all over the world, and 

 whose origin is uncertain. On the other hand, not a single undoubtedly 

 native speoies has attracted any notice as an insect pest in Ceylon. 



We have only to recognise these facts to appreciate the importance 

 of a properly conducted system of quarantine for all imported plants 

 and fruit. Our insular position in Ceylon, with but one main port of 

 entry, gives us a peculiar advantage in carrying out such a system. A 

 single quarantine station, with a single fumigatorium, will be sufficient 

 in our case to deal with the whole importations of the island. It is true 

 that, in spite of quarantine regulations, particular pests have found their 

 way into protected countries. In such cases failure must be attributed 

 to luoom^eteness of execution. And, though some few pests may have 

 evaded all precautions, how many others must have been refused entry? 

 The records of existing quarantine establishments give long lists of 

 dangerous insects detected on arrival and destroyed before they have 

 had the chance of obtaining a footing in the new country. 1 believe it 

 is the custom at most quarantine stations to examine imported plants 

 and fruit, and, if thay appear to be free from blights, to pass them with- 

 out treatment. But I maintain that not even the most experienced 

 entomologist could guarantee a plant as absolutely free from insect life. 

 Minute larvae and eggs may lurk beneath bud-scales, in the axils of 

 leaves, or in unnoticed crevices of the bark. To be really effective, 

 quarantine must be complete. Every live plant and fresh fruit should 

 be subjected to treatment, whether it appear to be free from disease or 

 not. 



The only sure way of reaching every hidden insect is by fumiga- 

 tion. If properly conducted, there is little danger of permanent injury, 

 to the plant. Even though some few delicate plants may be injured, or 

 actually killed by the process, this is a very small consideration in com- 

 parison with the damage that may be effected by a single imported pest. 

 What, for instance, must have been the pecuniary loss to the colony 

 from the ravages of the ' green bug ' — a loss that in all probability 

 might have been prevented. And compare this loss with the value of 

 all the delicate plants that have ever been imported into Ceylon ! But, 

 for such tender plants, it is possible to employ other treatment than is 

 recommended for hardy shrubs and trees. 



For wholesale fumigation of plants and fruit there is nothing to 

 i eq a il hydrocyanic acid gas, generated by mixing cyanide of potassium, 

 water, and sulphuric acid in certain proportions. This treatment is 

 cheap and effectual. The gas is of the most deadly nature, and will 

 penetrate every crack and crevice, and do its work thoroughly. The 

 application is quite simple. All that is required is a close fitting 



