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about tlie brandies, and I believe many of them would be destroyed by 

 washing the trees thoroughly with a dilute kerosene emulsion in the 

 winter. 



Many entomologists advise the use of kerosene emulsion to destroy 

 the eggs of Aphids and, as the eggs of the pear Psylla were similar, I 

 confidently expected to be able to easily destroy the exposed eggs 

 laid in the spring. In brief, the results of my experiments were, that 

 nymphs emerged from eggs which had been dipped in the following sub- 

 stances : Kerosene emulsion diluted to 33 per cent kerosene, or diluted 

 to 17 per cent, and heated to 130° F. ; jiure kerosene, benzine, turpentine, 

 pure, and as an emulsion; resin wash, triple strength; whale-oil soap, 

 and sulphide of potash wash, and carbolic acid and concentrated pot- 

 ash when diluted so as not to injure the buds, did not, kill the eggs. It 

 is thus seen to be impracticable to try to fight the pest in the egg state. 

 I notice in the last June number of Insect Life a communication which 

 records similar unsuccessful results in trying to destroy the eggs of 

 Aphids. In the reply the writer still adheres to the belief that they 

 may be killed by kerosene emulsion, but I have been unable to find any 

 account of previous careful experiments in this line. I believe that 

 there is too much theory and too little scientific practice put into our 

 recommendations for destroying not only the eggs of Aphids, but other 

 stages of other insects as well. 



Failing to check the pest in its egg state, I began experiments upon 

 the nymphs and very soon found that they were very susceptible to 

 kerosene emulsion even when diluted to 2 per cent kerosene. As they 

 congregate in the leaf axils, the emulsion would the more easily run 

 down the leaf petiole and destroy them almost as soon as they were 

 touched by it. Field experiments showed that fully 90 j)er cent of the 

 nymphs of all sizes could thus be reached and killed by one spraying. 

 This is, therefore, the stage in which to fight the -pest. 



Some claimed that last year there was so much honeydew that the 

 nymphs were comj^letely enveloi)ed in it, thus protecting them from 

 the insecticide. I have sometimes seen a few nymphs thus covered, 

 but I noticed that the rains washed off the secretion to a large extent, 

 1 therefore believe that a very practicable method of combating this 

 serious pest is to spray the trees with kerosene emulsion diluted to 2 

 per cent kerosene in the spring soon after the leaves have unfolded ; 

 the proper time in this State this year was about May 15. The best 

 time would be after a rain when the trees have become dry again. 

 There would then be less honeydew to protect the nymphs. A rain 

 soon after spraying does not lessen the destructive effect of the emul- 

 sion, which kills almost instantly. A second spraying a few days 

 later would be advisable. Of course other broods of the nymphs may 

 be destroyed later, but it is important that the early brood be checked, 

 for the greater part of the damage is done before June 15. 



The pest has not appeared in such alarming numbers this year as one 



