ROTJNDHEADED APPLE-TREE BORER. 33 



ovipositing females but could not be applied safely to trees on account 

 of the injury to bark or wood. All degrees of tree injury were ob- 

 tained, consisting of a slight yellowing and dropping of the leaves, 

 checking of growth, roughing and cracking of the bark, rank growth 

 of water sprouts, and killing outright. Some forms of protectors 

 caused the beetles to lay their eggs higher up the trunk than is the 

 custom, the only apparent advantage in their use being that the re- 

 sultant borers were easier to get at in the worming process. Some 

 other materials, such as white-lead paint, gave excellent results in 

 certain cases, and in others where the same material was used in 

 the same way, the female beetles bit through the coat of paint and 

 deposited eggs freely in the bark beneath. In practically all cases, 

 the time and expense required to make and apply protectors of this 

 entire class are greater than those called for in the worming opera- 

 tions, and the results in controlling the borers are less satisfactory. 



PROTECTORS USED AGAINST OVIPOSITING BEETLES. 



Since a large proportion of the eggs of this borer are normally 

 deposited within the bark of a limited space just above the ground, 

 it would seem a simple matter to cover or protect in some way that 

 part of the trunk so as to force ovipositing females to go elsewhere 

 to lay their eggs. A considerable number of such protectors were 

 tried over a series of years in a young apple orchard of a thousand 

 trees planted for experiment purposes at Elkins, W. Ya. The or- 

 chard was set in rows of 31 trees each, and most of the materials 

 were applied to trees of a single row, leaving the trees of an adjoin- 

 ing row untreated to be used as checks. In every case where paint- 

 like materials were used for more than one year fresh applications 

 were made annually. This was necessary for the reason that the 

 growth of the trees caused all substances to crack and expose areas 

 of the bark. The results of several of these tests are given below 

 in Table XI. 



Table XI shows that a considerable measure of control was ob- 

 tained by most of the protectors used. None, however, was entirely 

 satisfactory in every respect. 



In addition to the protecting materials mentioned in Table XI, 

 a large number of others were tested. These included proprietary 

 and commercial products in the form of paints, soaps, tar products, 

 whitewash combinations, viscous substances, nicotine washes, and 

 paper and metal contrivances, all intended to keep the female beetles 

 away from the bark either by offering mechanical barriers or by 

 making approach to the bark so difficult or disagreeable that they 

 would go elsewhere to oviposit. None of these was without objec- 

 tionable qualities, either from the high cost, injury to trees, or 

 lack of effectiveness in keeping out the borers. 



