354 State Horticultural Society. 



over again that the lime-sulphur spray can be made very effective 

 against this pest, but it is not easy to make or to apply thoroughly. 

 Unfortunately, the soap and oil sprays for this pest have often re- 

 sulted in considerable injury to the trees. But there are now on the 

 market several soluble petroleums which can be readily mixed with 

 water into a very stable emulsion. One can thus apply a dilute pe- 

 troleum spray with much less danger of injuring the trees. I have 

 been very favorably impressed with these soluble petroleums ever 

 since I first tried mixing them with water, and found how perfectly 

 they worked. Several experiment stations have already tested 

 these petroleums, and both favorable and unfavorable reports have 

 been published. I sprayed some trees last winter with the ma- 

 terial, and estimated killing at least 90 per cent, of the scales ; this 

 fall those trees were swarming with the insect, but I am not dis- 

 couraged. In September I located the pest in the orchard of one of 

 our best New York fruit growers, and it was found that 150 trees 

 in a block of about 600 were badly infested. The owner said the 

 trees were of no value to him as they stood, and that I might do 

 what I pleased in the way of fighting the pest. I decided to make 

 a thorough test of one of these soluble oils, and the whole orchard 

 was sprayed in October before the leaves were off, but after they 

 had done their duty toward developing next year's fruit buds. One 

 gallon of the oil was diluted with 15 parts of water, and a very 

 thorough application was made. I think we killed at least 90 per 

 cent, of the scales of all ages, from those just born to their mothers, 

 but the presence of the foliage on the trees prevented our doing the 

 most thorough kind of spraying. However, the breeding of the 

 pest was stopped, and another thorough application of the same 

 spray was made late in November, after the leaves were all off. I 

 hope to have hit five or more per cent, of the remaining live scales 

 with this spray, and if any live scales are to be found in March 

 next, a third thorough application of the same spray will be made. 

 The trees are six-year-old pear, and several older Japan plum trees, 

 and also include a few peach trees. 



This experiment should be a good test of the effectiveness of the 

 soluble oil as an insecticide, and also enable one to determine its 

 effect upon different fruit trees. From the above it is evident that 

 I have considerable faith in these soluble petroleums as insecticides 

 for the San Jose scale, and I am sure that many scales can be killed 

 with them, but I am not yet so sure about the results of the trees. 

 Therefore, I am not recommending anyone to use these substances, 

 except in a trial experiment on a few trees, The spray I used on the 



