31 
METHODS OF CONTROL. 
As with other species which feed beneath the surface of the ground, 
the carrot rust fly is a difficult one to reach with insecticides. Our 
principal dependence is therefore based upon methods of tillage which 
will serve to avert attack. 
Kerosene emulsion prepared in the proportion of one part to ten of 
water and sprayed upon the carrots along the rows with a knapsack 
or other sprayer, or sand, land plaster, or ashes, with which kerosene 
has been mixed at the rate of half a pint to 3 gallons, sprinkled along 
the rows, are (with the exception of crude carbolic acid at the rate of 
half a pint in 5 gallons) about the only applications which have been 
made with good results. In Canada, according to Dr. Fletcher, one. or 
the other of these applications should be made once a week through 
June from the time the roots begin to form, and particularly after the 
rows have been thinned. 
Late sowing has also been practiced to great advantage, several per- 
sons attesting its value. 
Rotation of crops should always be practiced in the case of such 
species as the present one, and this means the planting of a new bed 
each year as far as possible from land infested the previous season. 
Many of those who have complained of injuries have admitted planting 
carrots on the same ground year after year, and some have testified to 
the value of rotation. 
Destruction of the insects in stored carrots. — Where carrots are 
stored for winter use in earth this should be treated to destroy the 
larva? or puparia which leave the roots to enter the soil for transfor- 
mation. This may be accomplished in several ways: (1) By burying 
the earth deeply; (2) by spreading it in thin layers where it will be 
exposed to the elements; (3) where possible, by throwing it into pools 
where it will be frozen; or (4) by exposing it to heat or steam in any 
manner which may be most convenient. 
Treatment of the insect in celery beds. — Now that we know that this 
insect also infests celery, it is obvious that celery should not follow 
carrots nor carrots celery in rotation. Clean cultivation should be 
practiced, which means the destruction of all remnants after the celery 
crop has been harvested, and if the insect is found to destroy celery in 
store in the same manner as carrots, the earth, after the larvse have 
entered it, should be treated in the same manner as described above. 
After harvesting, it would be a good plan to give the celery fields a 
light raking or cultivating of sufficient depth to expose the larvae 
or puparia that they may be destroyed by frost; early the following 
spring, before the flies have time to issue, if the earth be plowed 
deeply, it will, with little doubt, have the effect of destroying most 
of the insects; and such as have not been killed by frost and survive 
