June, '19] 



FLUKE: BORDEAUX AND POTATO LEAF HOPPER 



257 



unsprayed, than they were on sprayed plants which were at least six 

 or eight feet away from the check plots. 



It should be noted that by August first the check plants of the Early 

 potatoes were in an advanced stage of tip burn while the Bordeaux 

 zinc plot was still healthy with but little tip burning. This plot held 

 up from a week to two weeks longer than the others. When the counts 

 were made the hoppers on these plants were nearly all in the first 

 instar. Of the late varieties there was a decided difference in appear- 

 ance between the checks and those receiving Bordeaux mixture, the 

 latter vines appearing much healthier. Tip burn appeared in a greater 

 or less degree on all the plants but showed most on the early checks. 

 In all cases the plants sprayed with Bordeaux mixture were healthier 

 and gave higher yields than did the checks or those receiving Black 

 Leaf 40. The nicotine sulfate, however, failed to kill the leafhoppers 

 due mostly to the curling of the leaves. Further experimentation is 

 needed to prove the repelling action of Bordeaux on the leafhoppers 

 but these few observations are given to show future possibilities. 



SpRiT Tests Against the Potato Leaphopper, 1918 



Total hoppers counted on 5 sprayed plants 476 



Total hoppers counted on 5 unapraycd plants I>71 



