. Entomological Division. 433 



the p^st is as yet unknown, and they will desire to know h.ow 

 tli(»y can prevent its gaining a foothold among their trees. Grow- 

 ers who raise all their own trees from pits will not be troubled 

 with the pest unless careless neighbors introduce it on stocks pur- 

 chased in infested regions. 



If it seems necessary td purchase nursery stock elsewhere, and 

 especially in regions known to be infested, it should be quaran- 

 tined and very thoroughly treated with an insecticide immediately 

 upon its arrival. Dip each tree in e^ither the diluted kerosene 

 emulsion or the tobacco decoction made as described above for 

 use against the branch formsL As the insecticide acts very quickly 

 the tree need remain in it but two or three minutes. This method it is 

 believed wiU effectually destroy all aphids that may be on the trees. 



Another method which would doubtless be equally effective is 

 the one used largely in California where the law requires that all 

 trees, plants, cuttings, grafts, buds, seeds, pits, or scions coming 

 into the State shall be disinfected upon arrival. The disinfection 

 is done by fumigating the trees, etc., with hydrocyanic acid gas, 

 a deadly poison. In fumigating, the trees, etc., are placed in an 

 air-tight tent or box, and for each 100 cubic feet of space in the 

 box or tent one ounce of fused cyanide of potassium (fifty-eight 

 per cent), one fluid ounce of sulphuric acid, and two fluid ounces 

 of water are used. The cyanide of potassium is placed in an 

 earthenware vessel, the water poured over it, the sulphuric acid 

 then added, and the box or tent closed tightly immediately and 

 kept closed for at least forty minutes. 



Every peach grower should take sufficient interest in the wel- 

 fare of his own orchard and that of his neighbor to treat in one 

 of the above ways all peach stocks purchased in localities where 

 the pest is known to be present, as in New Jersey, Delaware, 

 Maryland or Virginia. If this be thoroughly done our peach 

 orchards will have one less serious insect foe to fear. And the 

 growing nursery industry of New York State, which now has 

 nearly 500 acres devoted to peaches, constituting nearly fifteen 

 per cent of all the peach stocks grown in the United States, wiU 

 not suffer as it would were it known that this pest is liable to 

 accompany the trees sent out. 



MAUK VEKNON SLINGERLAND. 

 65 



