370 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



The following experiments made in the laboratory upon infested 

 leaves, show the action of solutions of various strength. In order to 

 retain the mites upon the leaves, the liquids were beaten into foam, 

 which was spread evenly upon both surfaces, care being taken to wet 

 every part of the leaf. 



(1.) Solution: 1 pound to 100 gallons. Free mites washed from the 

 leaf with spray and collected upon blotting paper, began to crawl away 

 as soon as dry, and showed no injury the following day. Eggs anil 

 molting young remained upon the leaf and were not affected. 



(2.) Solution : 1 pound to 50 gallons. Applied in foam. Free mites 

 in great part killed. Molting young and eggs not killed. 



(3.) Solution: 1 pound to 32 gallons. Adult mites all killed. Molt- 

 ing young in part killed. Eggs not killed. 



(4.) Solution : 1 pound to 16 gallons. Adult mites all killed and shriv- 

 elled, in two or three hours. Molting mites, about 80 per cent, killed. 

 Eggs, a large percentage killed. 



(5.) Solution : 1 pound to 5 gallons. Adult mites all killed. Molting 

 mites apparently all dead in two days. Eggs evidently affected, not 

 all killed, but many collapsed by the second day. 



(6.) Solution : 1 pound to 1 gallon. (This solution is nearly solid when 

 cold.) Mites all killed. On the second day all the eggs appeared col- 

 lapsed and dead. 



The whale-oil soap usually supplied by dealers is inferior to that used 

 in the above experiments. As an effective remedy for Eust-mite a solu- 

 tion of 1 pound to 5 gallons of water may be recommended. It should 

 be applied in early spring, before the new growth begins. Two or three 

 applications will be required, which should be made at intervals of one 

 week. The cost of the wash, at the ordinary retail price for the soap 

 (10 cents per pound), is 2 cents per gallon. 



Yery weak solutions may be made effective if used at frequent short 

 intervals, but the labor and expense of making the numerous applica- 

 tions required will be very great. 



A solution of 1 pound to 5 gallons will not injure the trees, but may 

 cause the blossoms to drop. No directions can be given as to the 

 greatest strength of solution that can be used upon blooming trees 

 without loss of fruit, as this depends largely upon the condition of the 

 tree. Solutions of 1 pound to 10 gallons can probably be safely used, 

 in most cases, and will be effective if several applications are made at 

 intervals of a few days. 



Sulphur. — The mites, both adult and young, are very sensitive to sul- 

 phur, and are readily killed by it in any form in which it can be made 

 to act upon them. The eggs, however, are not readily affected, and 

 even survive an exposure to the fumes, which will kill the plant. Fu- 

 migation cannot be resorted to without extreme danger to the life and 

 health of the tree. The finely powdered (sublimed) flowers of sulphur 

 does not affect the plant. It adheres more readily than might be sup- 

 posed to the smooth surfaces of the leaves, and especially when they 

 are roughened by the mites, it is not entirely washed away by heavy 

 rains. "Although it does not kill the eggs, it effectually exterminates 

 the free mites, which are sure to come in contact with it in their wan- 

 derings, and if it can be made to remain upon the plant, the young as 

 they hatch are also destroyed. 



Flowers of sulphur must therefore be regarded as one of the cheapest 

 and most effective remedies for Eust-mite, and it may be used to great 

 advantage in connection with whale-oil soap or other insecticides. It 

 may be suspended in water and applied in spray. With proper ap- 



