34 BULLETIN 1238, U. S. DEPARTMENT OF AGRICULTURE 



weight of coal-tar neutral oil [density of 1.12 to 1.15 at 20° C], applying 

 heat to the kettle until all of the pitch has melted and thoroughly mixed with 

 the oil, then removing the kettle and adding two more parts by weight of coal- 

 tar neutral oil and mixing the contents thoroughly. This product, known as 

 pitch neutral-oil mixture, can be poured and worked after cooling. 



The banding material is mixed as follows : 



Eighteen pounds of the pitch neutral oil or stock mixture and 70 pounds of 

 the coal-tar neutral oil are added to the mixing kettle and the stirrer started 

 working. In a few moments 12 pounds of hydrated lime are added slowly to 

 the mixture. When the contents have become of a uniform consistency 50 

 pounds of rosin oil [known as first run " kidney," having a viscosity of 52 

 at 100° C. tested with a Saybolt universal viscosimeter] are added and allowed 

 to mix for a few minutes, or until the contents begin to thicken, after which 

 20 pounds of coal-tar neutral oil are added and the contents allowed to mix 

 thoroughly. The stirring is then stopped and the material poured into con- 

 tainers and allowed to set for two or three days, and by the end of this time 

 the material has set into a semisolid state, of somewhat softer consistency 

 than cup grease. 



For use in the cooler seasons of cankerworm emergence, the 

 formula should be modified by the addition of a little more of the 

 coal-tar neutral oil. 



This material may be applied with a putty knife or a thin hard- 

 wood paddle directly to the tree, after first removing any loose 

 flakes of bark. It has proved fairly effective against the canker- 

 worm moths except in extremely heavy emergences, in which cases 

 bands 6 inches wide were bridged and crossed in a very short time. 

 For the cankerworm moths the most satisfactory band is one rather 

 thin and several inches wide, rather than the narrower bands which 

 are applied for the gipsy moth with a special gun. 



The bands should be examined at intervals, particularly during 

 the period when the moths will be likely to emerge in greatest num- 

 bers, and the surface renewed by stirring with a putty knife or 

 paddle whenever it has been bridged by foreign matter or the bodies 

 of moths, which, when numerous, will sometimes bridge a fairly 

 broad band, enabling the moths emerging later to pass without be- 

 coming entangled. One may determine whether the bands are doing 

 effective work by the use of a check band, placed above the first on 

 a tree here and there. Some of the moths on reaching the obstruc- 

 tion will not attempt to pass, but will lay their eggs below it. For 

 this reason, the band should remain effective until apple-blossom 

 time is over in order to protect the foliage from the larvae hatching 

 from such eggs. In severe infestations it will pay to continue the 

 barriers another month for the purpose of preventing the reascent of 

 any larvae which have dropped from the tree. 



Barriers of wire, tin, or lead were formerly used to quite an ex- 

 tent, but they are hard to fit perfectly to the irregular surface of the 

 tree trunk, and do not always prevent the passage of larvae hatching 

 from eggs laid below them. Barriers of cotton batting and other 

 loose, fluffy material are sometimes used, but are likely to become 

 matted down by rain, and are not on the whole as satisfactory as the 

 sticky bands. 



For the control of the fall species the bands should be in place at 

 least by the middle of October, and remain effective until the ground 

 is thoroughly frozen for the winter. With severe infestations they 

 should be renewed as soon as' the ground thaws with the first warm 

 days of late winter or early spring, in order to intercept any moths 

 whose emergence has been delayed. They should be kept effective 



