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of a well-made emulsion and the possibility of using much stronger 

 mixtures tlian has hitherto been advised. The necessity for such 

 strong applications will be appreciated by anyone who has attempted 

 to eradicate scale insects from plants. 



Winter applications. — Various winter applications have been recom- 

 mended J"or scale insects, notably the winter resin wash, formulated by 

 Mr. Coquillett, and the lime-sulphur-salt wash which has been claimed 

 to give very successful results in California. The occurrence of a new 

 peach scale {Diaspis lanatus) in excessive numbers on some experi- 

 mental peach trees in the Department grounds gave an excellent 

 opportunity to test for our climate the winter effect of various washes. 

 In addition to the two washes mentioned, kerosene and whale-oil soap 

 emulsion and pure kerosene were used. The applications were made 

 during January and February, and were very liberal, the bark of the 

 trunks and larger branches to which the scale is confined being 

 thoroughly wetted until the liquid ran down on the ground about the 

 bases of the trees. The first treatments were made with the resin 

 wash and the lime- sulphur- salt mixture. Very light rains fell after 

 the applications were made, but not sufficient to wash the lime from 

 the trees treated with this mixture. The lime-sulphur-salt mixture, 

 two months after the application, had not resulted in the destruction 

 of a single scale; the resin wash at standard strength had killed about 

 1*0 per cent, and at double strength about 50 per cent of the scales. 

 In April, or a month after the last examination, the amount of benefit 

 was unchanged, except that perhaps 5 per cent of the scales treated 

 with the lime-sulj)hur-salt mixture were dead. 



Another series of experiments was made with the kerosene mixtures, 

 namely, kerosene emulsion diluted 5 times, diluted 2i times, undiluted 

 emulsion, and the pure oil. These ai^plications were made March 10, 

 and five days later no injury was discovered to the scales in the case 

 of the diluted kerosene emulsion. On the tree to which pure emulsion 

 was applied the insects had assumed a dull, unhealthy color, and the 

 same effect, but not nearly so marketl, had resulted from the use of • 

 the pure oil. Five days later, or on the 20th of March, there were still 

 no certainly dead scales in the case of the diluted emulsions, but with 

 the pure emulsion the scales were all dead and rajiidly turning black 

 and drying up. On the tree treated with pure kerosene the scales 

 presented nearly the same condition as those treated with pure emul- 

 sion, perhaps 10 per cent still showing some signs of life. About the 

 1st of April an examination showed that the 5-times diluted emul- 

 sion had not killed a single scale. The 2i-times diluted emulsion had 

 destroyed about 10 per cent of the scales, the rest being apparently 

 uninjured. All the scales were dead in the case of the treatment with 

 pure emulsion and with kerosene alone. During April all the treated 

 trees bloomed abundantly and did not show any injury from the treat- 

 ment. 



