230 ANNUAL EEPOETS OF DEPARTMENT OF AGEICULTUEE. 



DECIDUOUS-FRUIT INSECT INVESTIGATIONS. 



Investigations of deciduous-fruit insects liave been carried on 

 under the direction of Dr. A. L. Quaintance, as formerly. 



Apple insects. — The studies carried on during the past few years 

 on aphids affecting apples have been fairly well completed, and 

 publications have been issued concerning the majority of them. The 

 extensive tests for some time in progress in the use of certain poison- 

 ous gases against the woolly aphis on the roots of orchard trees have 

 been completed. Although several substances were found effective 

 against the insects, more or less injury to the trees resulted in many 

 cases. Further experimentation is planned with other fumigants. 



The life-history studies of the roundheaded apple-tree borer are 

 Avell advanced. Field observations confirm the importance of the 

 destruction of certain native forest shrubs in which this insept breeds 

 principally. A related insect, the spotted apple-tree borer, has been 

 found to be a serious enemy of apple trees in portions of Michigan. 



The codling-moth observations have been continued. Biological 

 studies in the Grand Valley of Colorado, in cooperation with the 

 Colorado Agricultural Experiment Station, have been completed. 

 Experiments in orchards, to perfect a spraying schedule for Colorado 

 conditions and to determine the value of sprays for the control of 

 this insect in arid regions, are being continued. Further tests of the 

 automatic codling-moth band trap mentioned in my last report indi- 

 cate the usefulness of this apparatus as an adjunct in the control of 

 the pest, especially in regions where the insect is excessively injuri- 

 ous. Studies of tliis insect are being continued in the Pecos Valley in 

 New Mexico, where a special effort is being made to determine the 

 comparative effectiveness of dust and liquid sprays. Tests of poison 

 dust compared with poison sprays are also in progress in the Shenan- 

 doah Valley of Virginia. 



Grape insects. — A comparatively new grape pest has attracted 

 attention in California, namely, the grapevine mealybug, and at the 

 request of vineyardists a specific study of this insect has been begun 

 at Fresno. Thorough investigation of the life history is in progress, 

 and extensive tests of sprays and other remedies are under way. 



The large-scale spraying experiments against the grape-berry moth, 

 in progress in vineyards in northern Ohio, in cooperation with the 

 Ohio Agricultural Experiment Station, were completed successfully. 

 They confirm the earlier results obtained at North East, Pa., which 

 showed that this pest can be controlled by two thorough applications 

 of arsenate of lead (preferably in Bordeaux mixture) made by the 

 " trailer " method, the first immediately after the falling of the blos- 

 soms and the second two weeks later. This is an important improve- 

 ment over schedules requiring the late applications of sprays, which 

 usually result in discolored fruit at picldng time. A largely increased 

 vineyard acreage in northern Ohio now is being sprayecl under the 

 direction of the bureau. 



Peach insects. — Additional information has been obtained con- 

 cerning the life history and injuries of the peach borer, and much 

 work has been done with various fumigants in the effort to destroy 

 the borers at the base of the trees. It has been shown that carbon di- 

 sulphid, even in minimum doses, may cause more or less injury to 



