30 BULLETIN" 847, U. S. DEPARTMENT OF AGRICULTURE. 



21 pupal cells were found, 19 of which had been opened by wood- 

 peckers and the insects removed. 



During the winter of 1915 the writer had standing near his office 

 window a young apple tree in which there were known to be three 

 borers ready to pupate the following spring. The borers had been 

 protected previously by a wire screen but now the screen was 

 removed. On December 21 a male downy woodpecker, Dry abates 

 pubescens medianus (Swains), was observed to alight on the base of 

 the trunk and move about alternately tapping the bark and assuming 

 a listening attitude. Presently, with a few vigorous strokes, it drilled 

 through the bark at the point where the future exit hole of a beetle 

 was to have been and at once drew forth and swallowed a large borer. 

 (PL V, B.) A minute or two later it located a second borer, disposed 

 of it in the same way, and then flew away without further search. 

 Again, in January, 1916, the trunk of a young apple tree known to 

 contain full grown borers was planted in a natural position near the 

 same office window. A few days later a pair of downy woodpeckers 

 came to the tree and after a brief search the female was seen to re- 

 move and swallow a borer. A little later the male found and re- 

 moved another. The birds would move about over the trunk tapping 

 lightly with their beaks until the quarters of a borer were located. 

 Then with a few sharp strokes they would penetrate to the burrow 

 and remove and devour the insect. The female bird located and 

 removed her specimen through the partly prepared exit hole in less 

 than a minute, but the male drilled industriously for his nearly five 

 minutes, making during the time several openings into the wood 

 which extended in a line over the burrow made by the borer in 

 ascending the trunk to prepare its pupal chamber. 



Other observations were made which indicate that the hairy 

 woodpecker, Dryobates mllasus villasus (L.), also destroys the borers, 

 but this bird was not seen in the act of removing the insects from the 

 tree. 



METHODS OF CONTROL. 



Ever since the roundheaded apple-tree borer was first recognized 

 as a serious orchard pest, two principal ways of combating it have 

 been advocated : First, the worming process, in which the borers are 

 removed from their feeding places in the tree by the use of a knife 

 and other tools (PL IX, B) ; and, second, the covering of that portion 

 of the trunk of the tree where the eggs are most frequently laid with 

 some protective wash, paint, or mechanical device which will act as a 

 barrier against the female beetles during oviposition. Both of these 

 methods are commonly practiced in orchards and have been the lines 

 of most frequent and extensive experimentation by investigators of 

 borer injury and control. In the present studies, modifications of 



