118 
of a well-made emulsion and the possibility of using muck stronger 
mixtures than 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 for 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 (Biaspis 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 
20 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-sulphur- salt mixture were dead. 
Another series of experiments was made with the kerosene mixtures, 
namely, kerosene emulsion diluted 5 times, diluted 2£ times, undiluted 
emulsion, and the pure oil. These applications 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 marked, 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 rapidly 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 2^-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. 
