302 AISTNUAL EEPOETS OF DEPARTMENT OF AGRICULTURE. 



practical interest to growers. The introduction of codling-moth 

 parasites from the East to the State of Washington has resulted 

 in the establishment there of one species at least. Further attention 

 is being given to the matter of spray residues on harvested apples 

 and pears in Washington and Oregon. The work under y\-a.y in 

 California, as indicated in the last report, was successfullj^ com- 

 pleted and a report issued. A spray schedule was developed, which, 

 if followed by growers, will obviate almost entirely the presence of 

 spra}^ residues on fruit at harvest time. 



A number of other apple insects have been under investigation, 

 as apple leaf hoppers, apple maggot, etc. Manuscripts have been 

 submitted giving the results of several seasons' studies of canker- 

 worms and the bud moth. Observations are being made on the red- 

 banded leaf-roller, the false red bug, and the apple and thorn skele- 

 tonizer, this latter a rather recently introduced pest. 



The San Jose scale is again becoming troublesome in certain parts 

 of the country, and has been especially injurious in apple orchards in 

 the Ozarks. Special attention has been given to control of this 

 insect in bearing orchards at the Bentonville, Ark., laboratory, and 

 material progress made. A new dormant-tree spray has been de- 

 veloped, composed of 2 per cent engine oil thoroughly emulsified 

 with potash-fishoil soap, which has been found to be very effective. 

 In view of its cheapness and ease of application, the treatment was 

 largely adopted by orchardists in preference to lime-sulphur wash 

 and over 1,000 barrels of stock emulsion v»'ere used in Benton and 

 Washington Counties during the spring of 1922. No injury to trees 

 has thus far been noted from the use of this material as a dormant 

 spray, although in experimental work a spray containing as much 

 as 10 per cent of the lubricating oil was applied. This same spray at 

 weaker strength, as 1^ per cent, applied alone or in Bordeaux mixture, 

 has given good control of the hatching scales and the newly settled 

 young. It was further ascertained that a spray containing 1 per cent 

 of lubricating oil was about as effective as nicotine sulphate in the 

 control of the green apple aphis and far less expensive. In coopera- 

 tion with the entomologists of the Arkansas Agricultural Experi- 

 ment Station, careful biological studies of the San Jose scale in the 

 Ozarks are being made, special attention being directed to the fac- 

 tors resulting in its present unusual abundance and destructiveness 

 as compared with conditions in former years. 



Nut INSECTS. — As during the j^revious year, the two laboratories 

 engaged in nut-insect investigations were continued. The one at 

 French Creek, W, Va., gave special attention to miscellaneous in- 

 sects attacking nut crops, and the one at Brown wood, Tex., con- 

 tinued investigations of insects attacking the pecan. Many im- 

 portant facts have been found, leading to practical results of im- 

 portance. 



Grape insects. — The investigations of grape insects under way for 

 several years with headquarters at Sandusky, Ohio, in cooperation 

 with the Ohio Agricultural Experiment Station, have been continued 

 along the lines indicated in former reports, particular attention being 

 given to the grape leafhopper, grape-berry moth, and grape root- 

 worm. The grape-berry moth continues to be an important pest 

 throughout northern Ohio and certain localities in Michigan. Con- 



