212 



equally useful. Early spring spraying destroys both early larvae 

 and adults ; if necessary, a second spraying may be given to the 

 stubble after the first crop has been removed. The cost of spraying 

 varies according to the labour available, but has been worked out at 

 about 35. an acre. No injury to the lucerne nor to cattle fed upon it 

 seems to residt from the spraying. Pasturing as a control method is 

 limited to the extent of the area that can be thus dealt with economi- 

 cally. By far the most effective method consists in dividing the field 

 and pasturing the enclosures in rotation, turning all animals into each 

 portion in turn. This permits the weevils to deposit their eggs at a 

 considerable distance above ground, where they are destroyed by the 

 cattle. Harrowing is resorted to only if the field still requires treat- 

 ment after the first crop is cut. A temperature of 120° F. is fatal 

 to the insects, and this can be produced by covering the surface of 

 the field with a dust-mulch, which on becoming heated by the sun 

 destroys all stages of the weevil. The field must be dry and the 

 ground suitable for this treatment. The cost is about 13s. 6d. per 

 acre, and must be followed by irrigation to start the growth of the 

 second crop. Parasites of the weevil include an Ichneumonid, a 

 species of Bathyplectes, which has become acclimatised in Utah. As 

 many as 30 per cent, of the larvae present in mid-summer were found 

 to be parasitised, but owing to the rapid reproduction of the weevil 

 99 per cent, must be destroyed merely to prevent the actual increase 

 of the species. It is hoped that native American parasites which 

 have been reared from the weevils may prove helpful in control. 



In reply to a question concerning the possible spread of this pest 

 to the eastern States, the author stated that at high altitudes the weevil 

 is less destructive. In a climate where the weevils are not forced 

 into inactivity by the heat of summer, the generations would be more 

 spread out and feeding would be more continuous, but less concen- 

 trated, and therefore less harmful. This is probably the case in Italy. 



BuEGESs (A. F.) & Griffin (E.L.). A New Tree Banding Material 

 for the Control of the Gipsy Moth. — Jl. Econ. Entom., 

 Concord, N.H., x, no. 1, February 1917, pp. 131-135, 2 plates. 



A tree-banding material very similar to that used in the CTcrman 

 forests has been manufactured in the United States and is applied 

 by means of an instrument consisting of a cylinder in one end of 

 which is a small rectangular orifice. The cylinder is fitted with a 

 plunger, which is forced forward in order to press the banding material 

 slowly through the orifice. It is not necessary to scrape the bark 

 before application, the orifice being simply placed against the trunk 

 and the material forced out while the operator moves slowly round 

 the tree until it is encircled. 



Of several slightly varying mixtures experimented with, the one 

 which gave the best results consisted of a high boiling neutral coal- 

 tar oil, having a density of about 1-15 at 68° F., a soft coal-tar pitch, 

 resin oil and commercial quicklime. A weighed quantity of the 

 coal-tar pitch was transferred to a 10-gallon steam-jacketed kettle 

 and heated until thin enough to run. Twice its weight of the coal- 

 tar neutral oil was then run in and the mixture well stirred ; the 

 quicklime was slaked with a little water and was passed through 

 a sieve having 10 meshes to the inch ; 5 lb. of the pitch mixture, 16 lb. 



