266 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



linio-siil]>lini' wash, and othor sprays woro tested. The best results 

 wcrt' ()l)(aiiied wlicn (he liine-sulphiir wash i)rei)ared according to 

 the foriuuhi I-l-'J or 1-1—4 was applied in winter or early spring 

 while (he trees were still dormant. On lai'ge (i-ees i( is believed 

 (ha( a winter api)lieation of linie-sid])hur will hardly he thorough 

 enough under ordinary conditions to touch all of the aphis eggs. 

 On small trees, however, the method is exceedingly eil'ective. 



In New Jersey" it has been shown that the apple aphis may be ma- 

 terially lessened at any time during the growing season by spraying 

 with kerof^ene emulsion at the rate of 1 part to 12 parts of water, a 

 5 per cent mechanical mixture of kerosene and water, fish-oil soap at 

 the rate of 1 pound per gallons of water, or tobacco decoction of a 

 strength equaling 1 pound tobacco per 2 gallons of water. It is rec- 

 onnnended that j)articular attention be given to an ap])lication of a 

 contact insecticide just after the eggs have hatched. In later experi- 

 ments at the same station whale-oil soap at the rate of 1 pound per 4 

 to gallons of water was found very satisfactory. If any tendency 

 toward burning is shown, tobacco decoction may be used in its place. 



THE WOOLLY APHIS. 



The woolly aphis is generally distributed throughout the apple- 

 growing regions, but it is much more injurious in certain localities 

 than in others. At the Missouri Station * orchards infested with this 

 insect were treated by removing the soil for a distance of 2 feet around 

 the trunks of trees, and to a depth of 4 to G inches, after which from 

 2^ to 5 pounds of tobacco dust was distributed evenly about the tree, 

 being careful to place it also close to the trunk. The tobacco dust 

 w\as then covered with the soil and allowed to remain in this position. 

 In one instance, where fifteen trees were twice treated in this way 

 the w^oolly aphis appeared to be entirely destroyed, except at the roots 

 of two of the trees. Experiments were also made wuth carbon bisul- 

 phid, which, when purchased at the rate of 10 cents per pound, costs 

 about \\ cents for a treatment of each tree. The carbon bisulphid 

 was injected at the rate of 8 fluid ounces per tree in three holes from 

 1 to 2 feet from the trunk of the tree. Some injury was done to the 

 tree when the carbon bisulphid was injected into the soil too close to 

 the trunk. In comparing the action of tobacco dust with that of car- 

 bon bisulphid it was found that the tobacco dust requires more labor 

 to apply and operates much more slowly. It costs from 3 to 5 cents 

 per tree, but it remains active much longer than the carbon bisulphid. 



a New Jersey Stas. Buls. 143, 181. 6 Missouri Sta, Bui, 35. 



