117 



the injury was trifling, a very small percentage, perhaps 1 or 2 per 

 cent, of the early leaves turned yellow and fell to tlie ground, but I am 

 inclined to believe that this was merely the normal spring shedding of 

 the leaves, which is seen in nearly all plants, notably in the box elder; 

 and, in fact, it was about as noticeable on trees untreated as on the 

 treated trees. In the case of the Japan quince, however, with the two 

 stronger mixtures, namely, those with one-third and one-fifth kerosene 

 emulsion, a few yellow spots appeared on the leaves, and later, upon 

 handling the limbs treated with the strongest mixture, about one- 

 fourth of the leaves were found to fall off readily. These leaves, while 

 looking comparatively healthy and green, had evidently been injured 

 more than their surface appearance indicated. With number 2 this 

 peculiarity was almost unnoticeable, and with 3 and 4 no injury what- 

 ever was shown, nor did any further injury manifest itself throughout 

 the season in the case of any of the plants treated. 



These experiments would indicate tliat the kerosene emulsion can be 

 applied in much stronger dilution to tender foliage of growing plants 

 than has hitherto been supposed. Later in the season applications 

 were made to a large number of peach trees at the standard strength, 

 namely, diluted with 9 parts of water, with no injury whatever result- 

 ing to the trees, and a similar result attended the midsummer appli- 

 cation to the same trees. 



Having occasion to experiment in a large pear orchard, a number of 

 mixtures were used on July 31 on young pear trees. The foliage was 

 for the most part well matured and hardened, but in the vigorous 

 growth of the young trees there were more or less new and com- 

 paratively tender leaves. The mixtures used were the milk emulsion, 

 the whale-oil soap emulsion, standard summer resin wash, and an 

 emulsion made with the resin- wash soap and kerosene. The emulsions 

 were all used diluted in two strengths, namely, diluted with 7 and 9 

 parts of water, and the kerosene and whale-oil soap emulsion, diluted 

 also with 4| parts of water. None of these washes resulted in any 

 injury whatever to the pear trees, and their application was very 

 thorough, even to the point of excess. 



Some young trees on the Department grounds, presenting about the 

 same conditions of foliage, were thoroughly sprayed with the milk 

 emulsion diluted with Bordeaux mixture to the standard amount, 

 namely, 1 part to 9. In this case also the plants suffered no injury 

 whatever. The Euonymus bushes in the Department grounds were 

 also sprayed with various strengths of the kerosene and soap mixture, 

 the stronger mixtures being twice and four times the standard strength, 

 or diluted respectively with 4^ and 2^ parts of water. In neither case, 

 however, did any injury result to the plant, and the stronger mixture 

 of the two was the only one which was entirely satisfactory in destroy- 

 ing the Euonymus scale. 



I have considered it important to put these various experiments on 

 record to emphasize that little danger attends the prosier application 



