466 Report of the Entomologists of the 



Block II; two-year-old apple trees sprayed June 18 and again 

 June 25, with green arsenite, one pound to 100 gallons of water. 



Block III; two-year-old pear trees sprayed June 18 and again 

 June 25 with green arsenite as in Block II. 



Block IV; one-year-old apple grafts badly infested with canker 

 worms. This block was sprayed early in June with the green 

 arsenite, one pound to 100 gallons of water. A second applica- 

 tion of the poison was unnecessary. 



Results. — The green arsenite at one pound to 150 gallons of 

 water had but little effect on the beetles. Where the^ stronger 

 mixture was applied the effect was very apparent, after the second 

 application. But few live beetles could be found, and after the 

 third application no further injury to the stock was noticed. Al- 

 though most of the spraying was done on a bright warm day, the 

 most tender leaves did not show the slightest indications of hav- 

 ing been burned by the green arsenite. 



Block IV was freed from canker worms by one application of 

 the poison at the strength stated. 



Conclusions. — While these experiments should be carried fur- 

 ther before final conclusions are reached, the results indicate that 

 young grafts may be safely sprayed with the green arsenite, one 

 pound to 100 gallons of water, provided enough lime is added to 

 give the mixture a " milky " appearance. It may be here stated 

 that it is important to add the lime as it not only makes the mix- 

 ture spread and adhere to the leaf better^ but prevents burning 

 the foliage. 



Spraying Cut-Leaved Birch. 



These trees constituted a small block in one of the Geneva nur- 

 series. Nearly all of the trees were badly infested with thiips 

 [Thrips sp.] These are very small, almost microscopic insects, 

 which feed on the soft parts of the leaves, soon causing them to 

 wither and die. They are frequently very injurious, and are well 

 known to both gardeners and fruit growers. They are hard to 

 reach with insecticides, as they fly away as soon as disturbed by 

 the spray mixture. The trees in question were beginning to show 

 the injury which the insects were causing before the spraying was 



