EXPEEIMENT STATION EEPOET. 609 



A few leaves, wliicli were pretty well hit by the spray and bore a 

 number of parasitized scales, were placed in a jar, and later the 

 parasites emerged, showing that the material had not affected them. 



Later this same mixture was used on a Norway, a sugar and part of 

 a silver maple. Examination a day or two thereafter indicated that 

 the material had not injured the foliage, except in the case of a few 

 of the younger and tender leaves on the silver maple. 



A rosin-naphtha mixture was applied to a sugar maple May 29th, 

 at a strength of one part to twenty parts of water. Several days later 

 I found that the leaves were burned as badly as any of those receiving 

 the strongest mixture of soluble oil. 



Two soap mixtures were used. One of these, Tak-a-nap, was applied 

 June 9th to a Norway and a silver maple, at the rate of one pound 

 in four gallons of water. The leaves on the Norway maple showed 

 little or no bad effects, while those on the silver maple showed a very 

 slight burning at the edges. June 15th, sprayed a few badly-infested 

 twigs on which the egg masses were of good size^ with Tak-a-nap soap, 

 at the rate of one pound to four gallons of water, and a few others 

 with fish-oil soap, at the rate of one pound to five gallons of water. 

 Next day it was noted that on those sprayed with Tak-a-nap the egg 

 masses were discolored, but very little penetrated, while on those 

 sprayed with the fish-oil soap the solution appeared to have penetrated 

 the egg masses much deeper. An examination made some time later 

 showed the results slightly intensified. Those sprayed with the Tak- 

 a-nap soap remained in fairly good condition, while those sprayed with 

 the fish-oil soap became considerably matted and lost their cottony 

 appearance. However, Pulvinaria larva?, as well as parasites, were 

 obtained from both lots of twigs, so that neither material was 

 thoroughly effective. 



June 19th, used the fish-oil soap, at the rate of one pound in four 

 gallons of water, on a silver maple; at the rate of one pound to five 

 gallons on a silver maple and a sugar maple, and at the rate of one 

 pound to six gallons on a sugar maple, with the result that the leaves 

 on all the trees were more or less injured. 



It is apparent from these experiments that a mixture strong enough 

 to destroy the insects, except as larvae or recent sets, would seriously 

 affect the foliage. Eecent sets and larva? may be reached by com- 

 paratively weak mixtures, but as the period of emergence and setting 

 lasts about six weeks, it is not practical to spray. Moreover, by the 



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