1907 - ENTOMOLOGICAL S0CIP:TY. 73 



merely a few trees that were sprayed with the mixture at Guelph; almost 

 600 gallons of the spray were put on. Each tree was carefully done but 

 was only sprayed once. 



What Formula Shall We Use? 



One of the first points of interest is to determine what formula is most 

 satisfactory. While this is an important matter, yet there is room for a 

 considerable amount of freedom. In countries like California and some 

 other American States where there is very little rain, a weaker mixture 

 than will suit our conditions may be used with good results. I found that 

 the chief objection to using a formula as weak as 15 lbs. lime, 12 lbs. sul- 

 phur and 40 gallons water was that the spray was washed off the twigs too 

 quickly by the spring rains. It is very important, however, that the spray 

 should remain on all parts of the tree as long as possible. The lowest for- 

 mula that seemed to me satisfactory, from my own experiments and those 

 I observed elsewhere, was 20 lbs. lime, 15 lbs. sulphur and 40 gals, water. 

 This formula has given excellent results. For instance, Mr. W. H. Bunt- 

 ing, of St. Catharines, one of the most successful fruit-growers, has used it 

 for some years, and though the San Jose scale has been in his orchards for 

 a long time and is very bad in neighboring orchards, he keeps it under com- 

 plete control with lime-sulphur of the above strength. Many farmers, how- 

 ever, prefer to use a slightly stronger wash. The majority of those I met 

 in the St. Catharines district used 22 lbs. lime, 18 lbs. sulphur and 40 gals, 

 water. This is also about the average strength used at Grimsby, Winona 

 and Fruitland. There is no trouble whatever in spraying a mixture as 

 strong as this or even stronger, as I myself proved. New nozzles of the type 

 of the "Friend" allow such mixtures to be put on in a fine mist without 

 any trouble from clogging. There can be no objection then to a fruit-grower 

 using a mixture of this strength or even stronger except that where spray- 

 ing is done every year 20 lbs. lime, 15 lbs. sulphur and 40 gals, water give 

 practically as good results and the expense is considerably less. 



First Steps in Boiling. 



Having decided then that 20 lbs. lime, 15 lbs. sulphur and 40 gals, water 

 shall be the minimum strength, let us next consider the best way to go about 

 making the wash. After testing several ways, I found none more satis- 

 factory than the following : put about 13 gals, (about one-third of the total 

 40 gals.) of boiling water into the barrel. Turn off the steam and at once 

 put the 20 lbs. of lime into the water. (Care must be taken to use only fresh 

 unslaked lime). When the lime has begun to slake vigorously add the sul- 

 phur, which should have been made into a thick paste with boiling water 

 before the lime was added. The whole should now be stirred as well as the 

 boiling will permit. When the boiling begins to slacken, turn the steam on 

 again. Stirring should be repeated every five minutes or so in order that any 

 little lumps of sulphur may be more readily broken up and go into combin- 

 ation. Boiling must always be vigorous, so vigorous as to keep the contents 

 of the barrel in constant commotion and cause the liquid to splash up to the 

 top. 



How Long to Boil. 



One set of experimenters used to say that boiling should be continued 

 until the deep green color came, others said to boil until the orange or am- 

 ber shade was reached. When Prof. Harcourt and I visited the St, Catha- 



