171: P.. C. Entomoi.ogicat, Soc^ET^■ 



a very limited knowledge of Botany myself, I have found that little of 

 immense value in my collecting trips, and have often been puzzled by an 

 attempted description of some plant on which other collectors have per- 

 chance taken rare specimens. Hence I have ventured to bring to the 

 notice of this Society the value of some Botanical knowledge, so that 

 we may remind ourselves that (excuse the paraphrase) "it is never too 

 late to learn." 



EFFECT OF FUMIGATION ON CERTAIN INSECTS 



By W. H. Lyxe, Vancouver, B. C. 



The danger of nursery stock cari-ying objectionable insects from one 

 country to another might be entirely overcome if the stock could survive 

 the treatment necessary to destroy the insects. 



Fortunately the San Jose Scale (Aspidiotus perniciosus), is one of 

 the species of insects hydrocyanic acid gas will kill without injury to the 

 trees or shi-ubs exposed tp the fumes. Provided, of course, the correct 

 formula and exposure arte used. This, of course, has reference to the 

 ordinary application of the gas not applied under vacuum pressure. 



It is, of course, understood that the San Jose Scale, being ovovivi- 

 parous, there are no eggs to contend with, simply the old or young insects, 

 both of which are affected by the gas and so the extermination is com- 

 plete ; unless a very unique instance with which I happen to be familiar 

 may be taken as an exception. On one occasion, after fumigating some 

 apple trees infested with San Jose Scale, I examined a well developed 

 female specimen witli my liand lens and noticed a newly born specimen 

 almost attached to the old one. Within lialf an hour an examination 

 was made under the microscope and we were very much surprised to 

 discover three newly born specimens all alive. The old female was appar- 

 ently dead, but the young ones lived for several hours. There were 

 several other specimens on the same tree, but all were dead aftei- exposure 

 to the gas. 



Other species of Aspidiotus scale insects giving birth to living young 

 include ostreaeformis and hederae, on which the hydrocyanic acid gas 

 should be just as effective as with Aspidiotus perniciosus. 



Egg-Producing Scale Insects 



Aspidiotus aueylus and forbesi, Diaspis, Chionaspis, Mytilaspis and 

 Lecanium, from which the young hatch from eggs deposited by the female, 

 present another problem. The mother scale may be killed by the gas, 

 but the eggs are liable to survive its effect. 



Under the circumstances the only recourse is that of dipping the stock 

 in a caustic solution, such as lime sulphur, whale oil, soap and nicotine 

 or distillate oil emulsion. The hardy nature of the stock would suggest 

 the best formula to use. 



