62 Bureau of i^vKMEus' Institutes. 



with each lot. In spite of these precautions, the caterpillars on 

 the sprayed foliage ate very little for from twelve to thirty-six 

 hours while those on the untreated leaves fed most readily. The 

 same results were repeatedly noticed with the elm leaf beetle. 

 The more successful fruit-growers make a practice of spraying 

 every year; first as the buds are opening, second, just after the 

 petals have fallen and before the green calyx lobes have closed, 

 and then about seven to ten days later. Such treatment should 

 be amply suflficient to control all orchard pests which yield to 

 arsenical poisons. If four ounces of Paris green or other arsenical 

 •preparation is added to fifty gallons of Bordeaux mixture, we 

 have a very effective fungicide and insecticide combined, which 

 is of special value for the first treatment. If spraying is under- 

 taken, it most certainly should be continued year after year, be- 

 cause experience has demonstrated that it is far from wise to 

 await the appearance of a pest in force before applying the 

 remedy. 



As the arsenites lie in small particles on the surface of the 

 plant, it is evident that an insect drawing nourishment through a 

 slender, thread-like beak or proboscis from the interior of the plant, 

 would be unaffected by such poisons. We must therefore fight 

 sucking insects by using substances which will kill when thrown 

 on the insect. That is, use a contact insecticide like kerosene 

 emulsion, whale oil soap solution, etc. Success with contact in- 

 secticides is proportional to the number of insects hit. Spray to 

 cover the pests with the substance. Contact insecticides are to 

 be used whenever insect injury is accompanied by a wilting or 

 discoloring of the affected parts and there is no tissue eaten away. 

 The foregoing are general rules which must frequently be modi- 

 fied to meet special cases. 



Beware of frauds. — A word of warning in this connection may 

 not be out of place. Beware of remedies for which great claim* 

 of one kind or another are made. There are now forty-six ento- 

 mologists in the United States giving a large proportion of their 

 time to the study of insects and methods of controlling them, and 

 unless a remedy is advised by a well known authority, it will be 



