32 BULLETIN 847, U. S. DEPARTMENT OF AGRICULTURE. 



often injure small trees severely the first season. The proper time 

 for the autumn worming varies two months or more between the 

 southern and northern limits of the insect's range, and no definite 

 date can be given which applies to all localities. A safe rule is to 

 have the worming job over before the time arrives for gathering the 

 first winter apples. The borers continue to injure the trees during 

 warm weather of late autumn and early winter, often ejecting their 

 castings in the latitude of West Virginia as late as December 1. 

 It is best to prevent all possible injury by getting the worming done 

 previous to the press of apple-picking time. Trees should have a 

 second worming in the spring soon after the blossoming time of the 

 apple, as it is practically impossible to secure all the borers at one 

 examination. Borers are usually easy to locate by their fresh cast- 

 ings soon after apple trees bloom. (PL VII, B.) 



At present no cheaper or more effective method of combating this 

 borer is known than that of worming. In order to get best results, 

 however, the work in the orchard must be done thoroughly, and 

 near-by breeding places, such as scattering growths or clumps of 

 apple, wild crab, mountain ash, hawthorn, and service trees elimi- 

 nated either by destroying the trees or by worming. Many orchards 

 are wormed thoroughly every year, and just as regularly beetles de- 

 veloping in adjacent trees fly over the fence and provide annually 

 for other generations of borers. For most effective control, there- 

 fore, the worming operation should include not only the orchard 

 but the trees of the locality immediately surrounding the orchard in 

 which borers breed, and the trees should be examined twice annually, 

 first in late summer after the egg-laying season is past and again 

 in the spring after the blossoming time of the apple. 



WASHES, PAINTS, AND MECHANICAL PROTECTORS. 



Various materials and devices have in the past been applied to the 

 trunks of trees, either to prevent the female beetles from getting at the 

 bark to oviposit or to kill the borers while feeding in the bark or wood. 

 For preventing oviposition protective coverings, either of a liquid 

 or mechanical nature, have been tested, and, for killing the borers, 

 penetrating poisonous or irritating liquids have been recommended. 

 In the present investigations about 50 kinds of washes, paints, and 

 mechanical devices were tested as to their effectiveness in preventing 

 egg laying and for killing the borers within the trees. Many of these 

 materials were homemade or homemixed and many others were 

 commercial products purchased either from the manufacturers or 

 on the market. Nothing in the way of trunk protectors was tested, 

 however, that gave satisfactory results in all cases. Some applica- 

 tions afforded full or a considerable measure of protection against 



