46 ENTOMOLOGICAL NEWS. [February, 



DEPARTMENT OF ECONOMIC ENTOMOLOGY. 



Edited by Prof. JOHN B. SMITH, Sc. D., New Brunswick, N. J. 



" Insect Lime." More properly this should be "insect glue," because 

 the German word is " leim;" but the term " lime" has somehow or other 

 come into quite general use, and will probably be continued. " Raupen- 

 leim" is a product of Germany, of a jelly-like consistency, very dark 

 brown in color, with a flavor of carbolic acid in the smell, and is supposed 

 to retain its sticky qualities when exposed to the air, rain, etc., fora period 

 of from two to three months or more. It is used principally to trap in- 

 sects that crawl up and down the trunks of trees, and its usefulness for 

 that purpose has been demonstrated. It replaces effectually all those 

 devices like tin collars or troughs used for trapping canker worms, and 

 all bands of cotton, paper, or other material wherever they have been 

 recommended. In our own country this material has not been used to 

 any extent except in Massachusetts by the Gipsy Moth Commission, who 

 have found it useful within limits in their work against the Gipsy moth. 

 It is probable that after a time this substance, or some substitute for it, 

 will come into more general use in this country, and if some little modifi- 

 cation can be made in it which renders it somewhat more fluid, so that it 

 can be put on with a brush like thick paint, its field will probably be a 

 large one. One of the most difficult classes of insects to deal with are 

 borers, whatever the order to which they may belong. It is rarely that 

 we are able to reach the insects themselves in their burrows, and usually 

 we can only protect our trees by covering them with some substance that 

 is either repellant or forms a mechanical coating. In repellants I have 

 no faith whatever, unless the odor is absolutely poisonous, and then the 

 effect is not due to the odor, but to the poisonous action. Mechanical 

 coatings have been used with more or less success; but they have rarely 

 been complete enough to answer every purpose, and have in most cases 

 labored under the disadvantage of not being persistent in character and 

 requiring renewal at short intervals. Lime in some form has been very 

 largely used, and where the coating was properly kept up with very good 

 success. At the base of trees, like peach trees for instance, newspapers 

 and other similar coverings have been used, and in some orchards I have 

 seen wire mosquito netting used to protect the trunks of the trees from 

 the insects. In this case the object was to keep the adults from getting 

 at the trunk, so that they could not lay their eggs. In the other case there 

 was nothing to prevent the laying of eggs; but the lime, which is often 

 poisoned, would form a sufficient barrier against the very young larvae; 

 yet all these substances have not been quite satisfactory. The thing that 

 is required or needed, is a substance that is easy of application, that can 

 be put on so as to form an absolutely impenetrable coating, that will re- 

 tain its properties for at least a month, and that will not be injurious to 



