42 THE KEPOPiT OF THE Xo. 36 



hopper and the blast passage. It seems necessary also to apply it to the trees when 

 they are moist. Another defect is that the dust does not adhere nearly so well as 

 the liquid lime-sulphur especially on glossy fruits and foliage. This is somewhat 

 counteracted by the fact that one can use the dust on fruit a short time before 

 picking w^ithout fear of staining, but cannot do this with the liquid. 



I believe that some tests on Pear Psylla at Burlington, probably with hydratod 

 lime, have proved successful. 



I am also told that some tests in New York, possibly with tobacco dust, 

 promise well against aphids. 



Should the hopes of the advocates of the dusting n\ethod of spraying be realized 

 Ave can see a great field of usefulness for it not only on fruit trees, especially large 

 fruit trees, but also on valuable shade trees in cities and parks. It should be a 

 great boon in tlie control of the Elm Leaf-beetle, Tussock Mofh, Tent Caterpillars, 

 and many other biting insects. Leaf diseases on shade trees could also in some 

 cases be controlled. I believe it has already been t-ested on the Leaf -spot or Leaf- 

 blight of the horse chestnut. 



It should not be at all difficult to improve the outfit so that even the tallest 

 trees could easily be reached. 



Father LEoroLD: May I ask Prof. Caesar what is the cost of your spraying 

 outfit, that is, for the blower alone? 



Prof. Caesar: The total cost for engine, blower and hopper was $260; it 

 will be a little higher this next year, probably $275. Probably $150 or $140 would 

 be the price for the blower and the hopper; I think you could get the engine for 

 ' about $100. 



A Member: What horse-power engine did you use? 



Prof. Caesar : Two and one-half horse-power.. 



Prof. Brittain : Did you have anyone here contract lead poisoning from the 

 use of that dust mixture? 



Prof. Caesar: There would be a possibility of injury from the dust if you 

 were reckless and tried to spray against the breeze, but the spraying should always 

 be done, if possible, on a calm day, and you should spray at right angles to. any 

 little wind there may be. 



Prof. Brittain : I have been told of one experimenter who contracted a very 

 bad case of lead poisoning from using the dust spray. 



Prof. Caes<xVr : I sprayed a good many days this year, and I consider that the 

 danger from the dust amounts to practically nothing both to the eyes and to the 

 lungs. I should say, liowever, that I wore goggles part of the time. 



Prof. Brittain: I should think that the great weakness with this dust spray 

 would be that it does not control sucking insects successfully. Where scale insects 

 and sucking insects like Capsids are very abundant, that w^ould be a very serious 

 drawbacks 



Prof. Caesar : In a large part of Ontario we do not need to spray for Aphids 

 and our Capsids,, though they are bad in a few orchards, are very seldom bad 

 enough to necessitate spraying for them. 



Mr. Dearness: I' understood Prof, Caesar to say that the spraying for Scab 

 was done at an exceptionally favourable time, and I wish to ask what time that 

 was. 



Prof. Caesar: The Apple Scab is of course one of the interesting things 

 from the standpoint, of plant pathology. I found in our experiments— and I have 

 been spraying for Apple Scab for eight years — that the great danger period for 

 Apple Scab is either the period from the time the blossoms begin to b.urst on to 



