68 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



during the lattor part of June; or, still better, by collectino- a hun- 

 dred or so full-grown larva? about the last of May and placing them 

 in a shallow box, the bottom of which consists of a pane of glass, the 

 box containing about 3 inches of moist soil. Some of the larva? will 

 go through the soil to the glass surface, where their transformations 

 may be watched and the time of emergence definitely determined. 



In making the spray applications care should be taken to cover all 

 parts of the foliage. For thorough work, 100 gallons of liquid spray 

 per acre is necessary and a pressure of not less than 100 pounds should 

 be maintained. Two such thorough applications — one as the beetles 

 emerge, and another not more than a week later — judging from the 

 results obtained in our work of the past season, will prove sufficient 

 to reduce the infestation of this insect to a point where it will not 

 seriously atfect the vitality of the vines. 



The formula used in our experiments during the past season is the 

 Bordeaux mixture formula, recommended by the Bureau of Plant 

 Industry for combating the black rot of the grape, to which was 

 added 3 pounds of arsenate of lead, the latter ingredient being the 



insecticide. 



t<pr(iij formula rccoiuiiicndcd. 



Copper sulphate (bluestoue or blue vitriol) pounds — 5 



Fresh stone liiue tlo .^ 



Arsenate of lead do 3 



Water gallons— 50 



