246 EXPERIMENTAL FARMS 



1-2 EDWARD VII., A. 1902 



extent that the owner of an infested orchard may hold the scale measurably within 

 control and that at the same time the trees can by thorough treatment every year ba 

 kept in a condition to bear paying crops of fruit. 



Whale-oil soap and crude petroleum, applied carefully as recommended below, will 

 kill 90 per cent of the scales, and fumigation with hydrocyanic acid gas will, at a 

 moderate expense, kill every scale on trees small enough to be covered by tents, barrels, 

 boxes, or other tightly closing structures, of which the cost of manufacture and hand- 

 ling is not so great as to make the operation impracticable. What is possible on a few 

 trees, will in time be done on many if it can only be shown that it is a paying opera- 

 tion. Since experiment has shown that with the below described remedies a larger pro- 

 portion of the insects can be destroyed than are produced naturally every year, it is 

 only a logical conclusion that the trees will year by year become freer and freer from 

 this most pernicious enemy. I feel sanguine that with constant treatment, such as is 

 year after year practised for some other crop pests, even orchards infested by the San 

 Jose Scale may before long be rendered free of that pest. But regular annual treat- 

 ment is absolutely necessary while there are any living scales on a tree. Where in- 

 fested trees have been neglected for only a single summer, they have quickly become 

 coated over again with the scales so as to be almost, or quite as bad, as they were be- 

 fore they were treated. 



The three remedies which have been proved to be the best in Ontario and northern 

 Ohio are the same which were mentioned in my last report, but further experiments dur- 

 ing the past summer have added to our knowledge, as to the best way to apply them : — 



1. Whale-oil soap. — This is a trade name for a potash fish oil soap which can 

 either be made at home or purchased from firms in Canada, who have made a specialty 

 of manufacturing it, with only the required amount of moisture and with the proper 

 amount of potash. Two of the brands made in the United States, which have given 

 good satisfaction to those who have used them in Canada, are those of W. H. Owen, 

 of Catawba Island, Ohio, and Good & Co., of Philadelphia, Pa. To be efficient, these 

 soap washes must be made of the strength of 2£ pounds of the soap to the imperial 

 gallon of water, and to dissolve the soap thoroughly it is necessary to use hot water ; 

 the mixture to be applied in the form of a spray before it cools if possible. This, how- 

 ever, is not necessary, because owing to the soap being made with an excess of potash, 

 10 or 12 per cent, the mixture will remain liquid when it cools, even at the above 

 strength. The best time to spray the trees is just before the buds burst in spring. 

 Although, as a general statement, orchards treated with this soap wash in Ohio were 

 not so free of the scale as those which had been sprayed with a crude petroleum mix- 

 ture, still it is a significant fact, that the two cleanest orchards of all those examined 

 in an area of 35 miles across, which had been at one time infested and had been sub- 

 sequently in a certain measure cleaned up, had been brought to their present good 

 condition by the use of whale-oil soap. No very bad trees could be found in those 

 orchards, and it was only with difficulty that any scales could be seen. For peach 

 trees this remedy is decidedly the safest to use. Its only drawback is the cost of the 

 material. In large quantities it can be purchased or made for about 3| cents a pound, 

 and, of the strength above advised, it would require one and a half gallons of mixture 

 containing 3| pounds of soap to an average-sized full grown peach tree, making about 

 12 cents for material for each tree. The great advantage is that there is no danger 

 of injuring the trees, and, further than this, the amount of potash in the soap makes 

 it a decidedly beneficial application for the trees. There is good evidence that whale- 

 oil soap is an excellent remedy for the fungous disease known as the Peach Curl 

 {Exoascus deformans, Tul.) which for many years has caused much loss in Ontario 

 peach orchards. It is also useful against many other insects than the San Jose Scale, 

 particularly several kinds of scale insects, the Pear Psylla and others, which pass the 

 winter hidden beneath scales of the bark of fruit trees. 



2. Crude petroleum, where it ha3 been thoroughly applied, has had a decidedly 

 quicker and more fatal effect upon the scale insects than the whale-oil soap, but it i* 



