72 THE REPORT OF THE No. 19 



Scotch, Jack, and Dwarf Mugho, and also on the Norway and White Spruce. 



Remedies. — As a rule, there is no need of resorting to any remedy to con- 

 trol this scale as it is seldom sufficiently abundant to do much damage. If, 

 however, it should be found in such numbers as to injure perceptibly trees 

 in a lawn, kerosene emulsion can be used, but this would be impracticable, 

 nf course, in any place where there were a very large number of trees to treat. 



Parasites. — About one-third of the scales examined this year were found 

 to have been parasitised, apparently by a Chalcid fly. A species of mite was 

 also found preying upon them. Thus it is probable that we owe much of our 

 security again.st the rapid increase of this insect to these parasites.' 



THE LIME-SULPHUR WASH. 

 By L. Caesar, Ontario Agricultural College, Guelph. 



From time to time during the last two years questions have arisen in 

 connection with the lime-sulphur wash which have made the Entomological 

 department feel that there was need of a further study of this important 

 mixture in order that they might be able to give fuller and more definite in- 

 formation to fruit-growers. Accordingly Dr. Bethune and Mr. Jarvis, not 

 having an opportunity themselves to devote their attention to this subject 

 on account of the mass of other work to which they have to give their time 

 and energy, asked me to begin the investigation this year. 



After reading the best literature I could find on the subject and get- 

 ting valuable suggestions in this way, I began to make the mixture on a small 

 scale in the chemical laboratory, where I could use glass vessels and see 

 the different phases passed through, so far as there was any physical evidence 

 of these. It was my intention at first to attempt to study the chemistry of 

 the wash, but I soon found that this wovild make a whole season's work and 

 that in any case the field experiments were necessary first to show what chemi- 

 cal problems there were. This autumn Professor Harcourt of the Chemical 

 department informed me that his department intended, if possible, this win- 

 ter to study the chemical side of the wash. He asked me to let him have a 

 list of any chemical problems that had occurred to me in connection with 

 my work on it during the season. 



After some laboratory experiments I began my field experiments. Any 

 experiments, however, made at Guelph alone would be inadequate, because 

 we have no San Jose scale here, and because we are also free from a number 

 of plant diseases that are very troublesome in the more truly fruit-grow- 

 ing districts of the province. Hence, I determined to make a trip to the 

 Niagara district in the spring when the wash was being applied to the trees, 

 and again in the fall to see the results, and to interview the best fruit-grow- 

 ers to find out their experience with the wash. I tried, moreover, where- 

 ever possible, to supplement my own experiments by visiting particular or- 

 chards in other districts or communicating with men who were using the 

 spray. In these ways considerable information about the wash has been 

 obtained, although I am aware that it will require further experiments for 

 two or three years longer before we shall know all that we should about this 

 mixture. 



I shall not attempt to give any account of the details of the experiments 

 made, but rather will discuss the different points of interest in succession. 

 Before proceeding to deal with these points, I should say that it was not 



