19 



A man could band from 18 to 20 trees an hour, and it required one 

 and a half to two ounces of tanglefoot to make a three-inch band around 

 a mature Ben Davis apple-tree. The expense of banding would be 

 about $3 per acre. 



The results scarcely warrant reliance on this method as a satisfac- 

 tory control, but it may be serviceable when one of the more satisfactory 

 control measures to be discussed later can not be used. 



SUMMER SPRAYING WITH ARSENICALS 



Since the larvae of this species are leaf-miners they can not be 

 killed by arsenical sprays, and since the adults feed mainly on the under 

 side of the leaf an arsenical applied to the under surface, theoretically 

 should be effective ; but orchards sprayed regularly with arsenicals and 

 fungicides are as severely injured as those not sprayed at all. It was 

 the purpose of our experiments to ascertain whether it was possible to 

 devise an arsenical formula or a method of application such that the 

 weevil could be reached. 



Obviously, such a spray should be applied when all the beetles in 

 the orchard are feeding on the leaf surfaces. This occurs first when the 

 beetles leave their winter shelter as the foliage is expanding, and again 

 about mid-June when the insects have just become mature and have left 

 the mines. Many preliminary experiments were made with arsenical 

 sprays in combination with soap and flour paste as spreaders, and with 

 lime-sulfur and Bordeaux as fungicides. Adult weevils inclosed in cages 

 attached to branches of apple trees the foliage of which had been sprayed 

 on both sides with arsenate of lead usually all died within a week. 



The repellent effect of fungicides. — Early in the course of summer- 

 spraying, leaves were sprayed with arsenate of lead and water, and arse- 

 nate of lead in combination with either soap, flour paste, lime-sulfur, or 

 Bordeaux. When given a choice of these leaves and unsprayed leaves 

 the beetles fed about as freely on those sprayed with arsenate of lead 

 and water, either alone or combined with soap or flour paste, as they 

 did on unsprayed leaves, but they avoided leaves sprayed with arsenate 

 and water in connection with lime-sulfur or Bordeaux. It is possible, 

 therefore, that the addition of lime-sulfur or Bordeaux to the arsenical, 

 as is the regular orchard practice, renders the treatment incilfective by 

 repelling the weevils before they are effectivly poisoned. The following 

 experiment emphasizes this view : 



Adjoining rows of apple trees in a commercial orchard were sprayed 

 with an upshoot spray, one row with arsenate of lead and water and 

 the other with arsenate of lead and Bordeauif. Two days later many 

 dead weevils were on the ground under the trees sprayed with arsenate 

 of lead and water but hardly any under those sprayed with arsenate of 

 lead and Bordeaux. All the s])raying had been done on the same day 

 and in the same manner and the weevils were equally abundant on the 



