330 SCHOOL ENTOMOLOGY 



Mix one pound of Paris green or white arsenic colored with 

 a dye with 25 pounds of bran or middlings. Stir a quart or 

 two of cheap molasses into a gallon of water and moisten 

 the bran, stirring thoroughly, until it makes a stiff mash. 

 Do not add so much water that the mash will be thin and 

 will cake when exposed. Sow broadcast on infested fields. 

 Keep poultry out of fields thus treated. 



Hellebore. The powdered roots of white hellebore are 

 often used as an insecticide in place of arsenicals, especially 

 for currant worms and similar saw-fly larvae and other in- 

 sects affecting crops soon to be eaten, as the hellebore is 

 much less poisonous to man and animals. It may be applied 

 dry, diluted with 5 or 10 parts of flour, or as a spray one 

 ounce to a gallon of water. It is too expensive for use except 

 on a few plants in the yard or garden and, like pyrethrum, it 

 deteriorates with age. 



When properly applied arsenical insecticides are entirely 

 harmless to man and animals. It has been shown by chem- 

 ical analysis that cabbages properly dusted with Paris green 

 contain so small an amount that one would need to eat 

 twenty-eight of them at once to be poisoned. Of course, 

 instances of poisoning are occasionally recorded, for ignorant 

 people sometimes seem to think that an extra large amount 

 of poison will kill the insects "deader" and, therefore, apply 

 an unnecessary amount, particularly when dusting. 



2. Contact Insecticides. Contact insecticides are used 

 against insects with sucking mouth-parts and against soft- 

 bodied biting insects, which may be more readily destroyed 

 by them than by arsenicals. The chitinous skin of an insect 

 is not easily corroded and in many cases a substance strong 

 enough to penetrate this skin will also injure foliage; hence 

 only soft-bodied insects can be safely combated with cor- 

 rosive substances on foliage. It is absolutely essential 



