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insects from increasing to any serious extent by three applications at 
intervals through the summer, but he cannot expect to greatly reduce 
their numbers. Where three applications have been properly made 
I have seen healthy scales as abundant on the trees upon the advent 
of winter as they were in the month of April preceding. Our main 
reliance must be either upon the gas treatment or upon winter washes. 
Between November 20 and December 25, 1894, twenty-nine different 
washes were most carefully applied to badly infested trees in Charles 
County, Md. These applications were made either by Mr. Marl at t or 
Mr. Coquillett, or by both together, and the writer was present at some 
of the applications. The substances used and the results obtained may 
be briefly stated as follows : 
Whale-oil soap : 
1. Three pounds dissolved in one gallon of water. Fatal to all the scales on the 
trees sprayed with it. 
2. Two pounds in one gallon of water. Same result. 
3. One and one-half pounds in one gallon water. Fatal to ninety per cent of the 
scales. 
4. One pound in one gallon of water. Fatal to eighty per cent of the scales. 
5. One-half pound in one gallon of water. Fatal to one-half the scales. 
Resin wash : 
6. Six times summer strength. Resin, 120 pounds; caustic soda, 30 pounds: fish- 
oil, 15 pints; water sufficient to make 100 gallons. Fatal to all the scales 
on the tree sprayed with it. 
7. Four times summer strength. Resin, 80 pounds; caustic soda, 20 pounds; 
fish-oil, 10 pints; water sufficient to make 100 gallons. Fatal to eighty-five 
per cent of the scales. 
Kerosene emulsion : 
8. Pure. Fatal to ninety per cent of the scales. 
9. One part of emulsion and one of water. Fatal to eighty per cent of scales. 
10. One part of emulsion and two of water. Fatal to one-half the scales. 
11. One part emulsion and three of water. Fatal to thirty per cent of scales. 
12. One part of emulsion in four of water proved fatal to only a small percentage 
of the scales. (On potted plants in Insectary.) 
13. One part of the emulsion in six of water, fatal to a very small percentage of 
scales. (On potted plants in the Insectary.) 
Hard laundry soap : 
14. Two pounds dissolved in one gallon of water. Fatal to eighty-five per cent 
of the scales. 
15. One and one-half pounds in one gallon of water. Same result. 
16. One pound in one gallon of water. Fatal to sixty per cent of the scales. 
17. One-half i*oimd in one gallon of water. Fatal to twenty per cent of scales. 
18. One-fourth pound in one gallon of water. Fatal to ten per cent of scales. 
Concentrated potash lye: 
19. Two pounds in one gallon of water. Fatal to eighty-five per cent of scales. 
20. One pound in one gallon. Fatal to seventy-five per cent of the scales. 
21. One-half pound in one gallon. Fatal to one-half the scales. 
22. One-fourth pound in one gallon. Fatal to twenty per cent ot the scales. 
Fish-oil soap, homemade: 
23. One and one-half pounds in one gallon of water. Fatal to half the scales. 
24. One pound in one gallon. Fatal to twenty per cent. 
25. One-half pound in one gallon of water. Fatal to five per cent of the scales. 
12283 -Xo. 4 2 
