REPORT OF THE STATE ENTOMOLOGIST I909 25 



Using the data obtained in the preceding series as a guide, 

 more elaborate experiments were conducted in the cubical 

 box and its cages described on a preceding page. The larvae 

 in this series had not begun to crawl to any extent and were 

 therefore practically in a hibernating condition. It will be 

 seen by reference to the table that fumigation for 3 hours with 

 I ounce of cyanide to 100 cubic feet of space can not be relied 

 upon to destroy all the caterpillars in the various cages though 

 the diffusion of the fumes was checked by no more serious 

 obstacle than the open mesh of cheese cloth. In fact, the lack 

 of uniform action in the different cages and the apparently 

 feeble penetrative power of hydrocyanic acid gas was some- 

 thing of a surprise. A reference to the records of the various 

 experiments under this series shows that the results are more 

 or less contradictory and unsatisfactory, plainly indicating the 

 unreliability of hydrocyanic acid gas for the destruction of the 

 hibernating caterpillars of the brown tail moth. This is es- 

 pecially true if the caterpillars are in their winter nests and not 

 freely exposed. 



The tests with scalecide diluted one part to 20 resulted in the 

 death of all the caterpillars even when the period of immersion was 

 limited to half a minute. 



Codling moth 



Carpocapsa pomonella Linn 



The codling moth must be regarded as one of the most injur- 

 ious of our fruit insects, since it occurs throughout the apple- 

 producing sections of this country. The apple worms ar young 

 of this pest may be found in from 25 to 60 or more per cent of 

 the fruit in many regions. This gives an idea of how very in- 

 jurious it may be, since the value of an apple is seriously affected 

 by the presence of the apple worm. Dr S. A. Forbes, State Ento- 

 mologist of Illinois, in 1887 estimated the annual loss caused by 

 this insect in that state at $2,375,000. A similar calculation for 

 Nebraska in 1892 placed the damage at $2,000,000, while in 1898 

 the late Prof. M. V. Slingerland estimated the annual loss caused 

 by this insect on the apple and pear crop of New York State 

 at $3,000,000. An estimate of the injury for the entire United 

 States, made in 1908, puts the damage at $12,000,000; aside from 

 the cost of spraying, which latter amounts to from $3,000,000 to 

 $4,000,000 [Quaintance '08]. Those conversant with the situ- 



