18 



HOW TO CONTROL THE PEAR THRIPS. 



Figure 10 shows an unsprayecl tree at blossoming tinie. The 

 unsprayed trees gave a yield of less than one-fourth box per tree, all 

 of wliicli was scarred, misshapen, and unmerchantable; but counting 

 them as No. 2 pears, at 50 cents per box, gives a return of about 

 12^ cents per tree. 



According to Mr. Swett, the spraying, including material, labor, 

 and all expenses connected with the operation, cost less than 25 cents 



Fig. 10.— Swett pear orchard at time of blooming. Unsprayed trees, sprayed portion of 

 orchard la background. (After Swett.) 



per tree for the 550 trees. This, plus the value of the crop (12^ cents) 

 from the check trees, gives 37^ cents. Subtracting this from the S2.60, 

 value of the crop per tree in the sprayed block, leaves a net gain of 

 S2.125 per tree, or approximately S225 per acre, or a return of over 

 900 per cent on the investment. 



