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AiV ECONOMIC ENTOMOLOGY. 



vent injury by canker-worms, because it hinders the female from 

 reaching the branches to lay her eggs. In the same way, trees 

 cleared during the winter of the egg masses of the vaporer moth 

 or of the sacs of the bag-worm may be kept cleared during the 

 year following by a band of these materials. It is said that 

 raupenleim, under the influence of cold nights, becomes too 

 hard to be effective, but this is not the case with dendrolene. 



A word of caution must be added. Both of these materials 

 penetrate to some extent, the dendrolene more than the raupen- 

 leim, because it never becomes hard and never dries. On thin- 

 barked or very young trees, if it is left on continuously, it will 

 check the growth of the bark, kill the outer layer, and may in- 

 juriously affect the inner bark or sap-wood. This is especially 

 true of peach-trees, and on such the materials should not be 

 applied very heavily, and should be washed off after midsum- 

 mer with some potash wash. Both raupenleim and dendrolene 

 dissolve readily in benzine, turpentine, or kerosene, and they 

 combine easily with any caustic ; hence the bark can be cleared 

 without very much trouble after the danger season is over. On 

 old trees, where the outer layer of bark is no longer active, no 

 danger is to be apprehended. Where trees are banded against 

 the canker worm or similar insects, the easiest way would be to 

 first tack a band of heavy wrapping-paper close to the trunk and 

 apply the material to that. It should be smeared over the edges 

 of the paper to the bark, so as to prevent any insect from getting 

 under it, and when the danger season is over this band can be 

 cut away without trouble, leaving only a narrow ring of the 

 smear, which could do no harm. Where protection against 

 borers only is sought, all injury can be avoided by mixing 

 the dendrolene with dry earth or with land plaster, weight for 

 weight, which will not reduce its value as a covering, but will 

 diminish its penetrating qualities. 



Lime is an exceedingly good preventive, applied in the form 

 of whitewash. Fruit-trees that have the trunks whitewashed 

 early in spring will be apt to remain measurably free from scale 

 attack, and if it is appHed fresh, a great many of the scales already 

 upon the trunk will be killed. It is an advisable thing, when 

 Bordeaux mixture is applied, to use plenty of Hme, especially 

 upon the trunks and branches of the trees, because no scale in- 



