1901 ENTOMOLOGICAL SOCIETY. 



working hard on this subject, and, from the progress which has aheady been made, it is probable 

 that before long their careful experiments (which it is of the utmost importance should be con- 

 tinued) will give results by which the danger of injuring the trees by inexperienced workers 

 will be reduced. Crude petroleum may with care be applied to healthy peach trees as strong as 

 20 or 25 per cent, of a mechanical mixture with water, but it is very difticult to mix properly, 

 and if applied carelessly or by reckless or inexperienced men there is great risk of the trees 

 being killed. It is not always easy to detect when a tree is enfeebled, and injury may some- 

 times result to trees which are apparently healthy, but which on examination will be found to 

 have suflfered fiom some other cause. In applying crude petroleum, experience seems to show 

 that one great difficulty is to get a pump which will always throw the exact percentage of oil 

 that is shown by the oil gauge. A perfect pump has never yet been produced and this has 

 always been a difficulty. When in Ohio recently, the speaker was much pleased to hear the 

 London Spramotor Co. pump spoken of in the highest terms, but even this is susceptible of 

 considerable improvement. Another danger may arise from the operator going over his work 

 twice, and of course in that way depositing on the tree twice the percentage of oil necessary. 

 Mr. Fisher's plan is to use not more than one tjuart of crude oil costing 2 or 3 cents to each tree. 

 The crude petroleum has two great ad van' ages over other remedies if experiments will show us 

 how we can use it without danger to the trees. It is exreedingly cheap, and it leaves a deposit 

 on the trees even after the volatile portion has evaporated. This deposit is vaseline and has 

 the double advantage of showing clearly on the trees what parts have been sprayed and at the 

 same time rendering the bark unsuitable for the young scales to settle upon. 



[Some striking examples were here exhibited of bark taken from the two sides of a badly 

 sprayed tree, one showing plainly the residue of the petroleum and no living scales, the othtr 

 showing no sign of oil and thickly caked over with living scale insects. One piece of bark had 

 on one side of it masses of dead scales as far as the oil had reached and beyond that, where there 

 was no oil, a thick coating of living scale insects.] 



Crude petroleum, therefore, is an effective remedy, but great care must be exercised 

 in using it. The great danger will be next year. Carefully watched over and helped 

 by Prof. Webster and his assistants in Ohio and by Mr. Fisher and his assistants in 

 Ontario, remarkably good results have been obtamed by some fruit growers ; very little 

 harm has been done to peach trees and none at all to apple, pear and plum trees. 

 This state of afiairs might probably engender a spirit of recklessness, and the speaker was afraid 

 that next year there would be much loss from fruit growers using the crude oil recklessly or 

 carelessly. There was no doubt at all that many who had even purchased crude oil this year 

 had abstained from using it, for fear of injuring their trees, but had watched the outcome of 

 their neighbours' experiments. As no cases of injury had occurred, a great many trees would 

 be treated next year. It was therefore most important to advise caution. 



(3) Fumigation. The most effective remedy is fumigation with hydrocyanic acid gas, which 

 will destroy every living insect, but which if applied as recommended will do no harm at all 

 to the trees. For small trees this has proved very useful, but for large trees the necessary tents 

 and apparatus are expensive and there are difficulties which have yet to be overcome in the way 

 of getting the gas equally diffused beneath the tents. 



Summing up what he had brought before the meeting. Dr. Fletcher claimed that, 

 notwithstanding the great danger which still exists from the presence of the San Jose 

 scale in Canadian orchards, the experiments of entomologists had provided remedies which 

 were as practicable and as effective as those which were used foi many other injurious insects, 

 and that by their regular use trees could be kept in health and in a bearing condition. 

 He would not believe that the extermination of the San Jose scale from Canadian orchards was 

 an impossibility. What could be done on one tree could be done on many. Combination, and 



