1907 ENTOMOLOGICAL SOCIETY. 79 



amples that could easily he given from any farmer who has carefully used 

 this wash against the scale. The fact is that wherever a man says he has 

 not got good results against the San Jose scale from the use of lime-sulphur, 

 it will turn out on close investigation to have been due to some fault in pre- 

 paration or manner of application. The wash is at present the cheapest 

 and most effective remedy for the San Jose scale in Ontario. 



The Oyster-Shell Scale. 



If we take Ontario as a whole we shall probably find that more injury 

 is being done at present to fruit-growing by the Oyster-shell scale than by 

 the San Jose, simply because the former is abundant in almost every orchard 

 while the latter is limited to only a few districts. Consequently a good 

 remedy against the Oyster-shell scale would be a great boon to the province. 

 Whether one year's experiments are enough to decide this question is a 

 matter of some doubt. I have endeavoured to make my experiments suffi- 

 ciently extended to draw accurate conclusions. I have also visited several 

 apple orchards in different parts of the province to compare results. It has 

 been more difficult, however, to determine the effect of the wash definitely 

 than one would have thought. The reason for this is, that owing to the 

 cold, backward spring and the unfavorable weather which followed soon after 

 the hatching of the eggs a very large proportion of the young scales, even 

 on unsprayed trees, died before reaching maturity. When there were so 

 many dead scales it naturally required much more careful work to determine 

 accurately the effects of the wash. I found that on the trees that were 

 sprayed before the middle of April almost all the eggs hatched out; on those 

 sprayed about the middle of April much fewer, and on those sprayed in 

 May when the buds were bursting, only a small percentage hatched. In 

 other words wherever the wash remained well on the tree and covered it, 

 there were very few eggs hatched compared with the cases where it washed off 

 before the hatching season. Not all the eggs, however, on any tree were 

 killed. I found practically the same results in other orchards. But some 

 farmers, whose orchards I had not a chance to visit, reported that the wash 

 had been useless. I think the majority of fruit-growers who have tried lime- 

 sulphur only once or twice for the Oyster-shell scale have not been satisfied 

 with the results. I believe the reason for this is largely that they sprayed 

 too early in the spring and did not cover the trees so thoroughly as they 

 should ; in short they did not drench the trees from top to bottom. Had 

 these points been attended to they would have killed a large percentage of 

 the scale, though not all in one season. I have observed that where orchards 

 are sprayed every spring for a number of years in succession there are prac- 

 tically no Oyster-shell scales left. But it is not enough to examine the 

 trees soon after the eggs have hatched ; they should also be examined later 

 in the season to see what proportion of the young larvae has matured. I 

 find that on the trees that showed the m.ost successful results in July, it is 

 difficult to discover a single living scale this autumn. Yet one should not 

 draw inferences rashly from this condition of affairs ; for as I have mentioned 

 above a very large percentage, apparently as high as 75 per cent, of the 

 young scales died even on the unsprayed trees here this year. If then we 

 are to judge by the earlier results we can only say that lime-sulphur 

 IS not a perfect remedy for Oyfster-shell scale if it is only to be 

 applied once ; but that if it is put on late in spring and repeated for several 

 years m succession it gives excellent results. For a single application I be- 

 lieve kerosene emulsion or flour-kerosene put on when the eggs have just 



