APPLE GROWING IX CALIFORNIA. 87 



During the month of June, according to O. E. Bremner, wings are 

 developed and a migration takes place from the apple to some interme- 

 diate host, which has not yet been discovered. The writer has observed 

 this habit of the louse in Colorado, and H. F. Wilson reports that a 

 similar migration takes place in Oregon. Mr. Bremner, who has done 

 more work <>n this species in California than any one else, states that 

 he has found the aphis on careless weed (Amaranhis retroflexus) , but 

 does not ivfx.rt having found it colonizing or feeding upon this plant. 



In the fall winged lice return to the apple and produce sexual forms, 

 the females of which lay eggs for the perpetuation of the species. 



Control. 



The very early hatching of the eggs makes it necessary that a spring 

 tivatiiit-nt for this pest be made accordingly. The writer has found 

 hatched lice of this species in February in Colorado, and there are no 

 doubt seasons in California when just as early hatching would take 

 place. Professor Wilson reports finding them in Oregon as early as 

 February 22d. in 1912. The stem-mothers become quite resistant to 

 contact sprays as they approach maturity; also, because of the protec- 

 tion of foliage at this time, spraying is often done with very poor suc- 

 cess. The ideal time to spray is just as the eggs are through hatching, 

 and while no date can be set, the time will conform closely to that of the 

 swelling of the buds. Such work should not be neglected until the 

 blossoms begin to appear, as this is too late for the best results. 



Professor Wilson recommends an early spring treatment with a combi- 

 nation of lime sulphur and Black Leaf "40." Mr. Bremner has had 

 splendid success with fall treatments when the sexual forms of the lice 

 are present, using a crude oil emulsion formula which is made as follows : 



"Place 88 gallons of water in the spray tank and add 1 to 2 

 gallons liquid soap, depending on the softness of the water used, 

 diluted with about an equal amount of water. Agitate until 

 thoroughly mixed and then with the agitator running add 10 gal- 

 lons of crude oil." 



A second formula recommended by Mr. Bremner follows : 



' ' Dissolve 10 pounds of whale oil soap in not less than 10 gallons 

 of water by boiling ; slice the soap and it will dissolve more quickly. 

 Place this in the spray tank, which should contain about 10 gallons 

 of water. Thoroughly agitate and add enough water to make 90 

 irallons. then add 2 pounds of caustic soda (concentrated lye), dis- 

 solved in water. With the agitator running add 10 gallons of crude 

 oil slowly." 



Either formula is said to be effective and spraying should be done 

 about November 25th in the Sebastopol section, where Mr. Bremner did 



his work. 



Other Species of Apple Plant Lice. 



The three species already treated are the only ones of any importance 

 that have been taken on apple in California. Occassionally other species 

 are found in limited numbers. C. P. Gillette and E. P. Taylor, in 

 Bui. 133 of the Colorado Experiment Station, and H. F. Wilson in the 

 Biennial Crop Pest and Horticultural R IM>I-I. 1911-1912, of the Oregon 



