No. 6. DEPARTMENT OF AGRICULTURE. 3»6 



ten. feet high, and the amount of grain contained in it does not mat 

 ter. To advantageously use the bisulfide in a bin, it may be di- 

 vided between several dishes set on top of the grain, and as it be- 

 j.nus to pass off as a gas into the air at once, the lid should be closed 

 as soon as the bisulfide has been placed in the dishes. The gas it 

 forms is heavier than the air and sinks through the grain, killing 

 all the insects it reaches. 



Two precautious in using this method should be mentioned. 

 Avoid breathing the gas as far as possible as it is very disagreeable 

 and in sufficient amount might be injurious. Avoid using the gas 

 near flame or much heat of any kind as it catches fire easily and a 

 lighted pipe in. the mouth of a workman close by, or a lighted 

 lantern within a few feet of the bin during the time treatment is go- 

 ing on might produce serious results. No injury of any kind is 

 caused to the grain by this fumigation, and seed wheat seems to be 

 as good for sowing afterwards as before. 



This method of fumigation is also excellent for the destruf^tion 

 of the pea and bean weevil and other insects, and can also be used 

 for the destruction of insects in cereals, meal, ground tobacco, and 

 in fact in anything which can be placed in a box or bin tight enough 

 to prevent the escape of the fumes of the bisulfide for a period nf a 

 day or more. 



THE CODLING MOTH. 



(Cydia pomonella Linn.) 



The Codling moth is perhaps responsible for more of the loss to 

 our apple crop than any other insect. Its caterpillar, generally 

 called the "apple worm," begins its attack soon after the fruit forms 

 in the spring and destroys multitudes of apples before they are more 

 than one-third grown. These are seldom taken into consideralion, 

 only those which are wormy later in the season being noticed. But 

 these form a large proportion of the gathered crop where no treat- 

 ment for the control of this insect is carried out, and the loss in the 

 form of second or third class, where first class fruit could otherwise 

 be obtained, reaches millions of dollars nearly every year — a loss 

 which is wholly unnecessary as it can in large measure be avoided. 



Life History. 



The Codling moth spends the winter in the caterpillar stage 

 snugly hidden under some loose piece of bark on the trunk of the 

 apple tree or in equally protected places near by. In April usually, 



