440 



AN ECONOMIC ENTOMOLOGY. 



powerful contact poison as against plant-lice, saw-fly and other 

 slugs, and most small naked caterpillars. It may !)(.• mixed with 

 twice its bulk of cheap flour, and if allowed to stand forty-eight 

 hours, in a closed jar, all parts of the mixture will be equally 

 effective. A destructive tea may be made by sleeping one ounce 

 in one quart of hot water and diluting with enough warm water to 

 make one gallon. This is excellent for si)rays on house or garden 

 plants infested by plant-lice, and is the cleanest of all insecti- 

 cides used for that i)urpose. In the lield the cost is too great 

 to make the material available, and its rapid iKterioration on ex- 

 posure to the air limits its range of usefulness. When eaten, or 

 when brought into contact with the surface of a larva it causes 

 convulsions, vomiting, and, in a short time, death. It has been 

 used by burning to drive out flies and moscpiitoes, and the smoke 

 acts as a narcotic and repellant ; but the insects recover in a 

 short time. 



White hellebore is the ground root of the Veratrum album, 

 and has rather a narrow range of usefulness. It is almost si)ecilic 

 in its action on saw-fly larvae, and affects those insects in the 

 same manner as pyrethrum. Outside of this its action is similar 

 to that of pyrethrum, but much less violent, and very little is now 

 used except against currant worms. It may be applied dry, as a 

 powder, or as a decoction, two ounces steeped in boiling water, 

 being diluted to make one gallon of spraying mixture. This 

 same decoction has been highly recommended as against the 

 cabbage maggot ; but the reports are too contradictory to make 

 it a safe reliance. As a contact poison the material remains 

 effective for a short time only ; but as a stomach jjoison remains 

 active for several days. 



Tobacco has much the widest range of this class of materials, 

 and may be used dry or :is a decoction. If used dry it should be 

 ground very flne, and the dust is fatal to many plant-lice and 

 small naked larvcC of all orders. As a coarser powder it is useful 

 against root-lice, especially those on peach-trees, by being worked 

 liberally into the top soil o\'er tlie root system. As the toljacco 

 is worth nearly as much as it costs as a fertilizer, a double advan- 

 tage is gained from its stimulating effect. Ground tobacco has 

 been used with some success around cabbage plants to prevent 

 attacks by maggots, and in melon hills to prevent injuries by the 

 striped beetles. Stems around fruit or other trees are unde- 



