98 



'I'he Canadian Hoki iclmi ukisi, 



Vig. 30 shows a section of one of ihc leaf spots, and fig. 31 a section ol the 

 skin of an apple with scab bursting up thrt)ugh the cuticle, or outer skin, both 

 magnified 200 diameters. The mycelium, or ])lant body of the fungus, resembles 

 a dense mass oftissue composed of dark-brow n walled cells. These do notix-netrate 



Fi.i. 30. 



Fic. 31. 



the cuticle, or inner skin, but grow between it and the epidermis, or outer skin, 

 which they soon burst open, and send up brown threads on the ends of which 

 are borne the spores for the propagation of the fungus. 



These latter are so tiny, that it would require 3,200^ 

 side by side, to reach an inch. They germinate in 

 moisture at a temperature of 50° F., in about eight 

 hours • and the germ tubes have power to penetrate 



, , ... Ill- F'" 32.— Spores of fungus 



healthy skin and thus quickly spread the disease. of Apple Scab, one germ- 



But our readers will be more interested in the sue- '"* '"^' 

 cess attending the use of remedies, than in the life history of the fungus. 



Prof. Scribner in his report of 1887, recommended spraying the trees in 

 early spring before the buds begun to expand, with sulphate of iron, 4 lbs. to 4 

 gals, of water ; then, after fruit is set, with Bordeaux mixture. More recently, 

 Prof. Taft and Prof. Trelease, have highly commended the use of ammoniacal 

 copper carbonate, as has been fully stated in our pages. 



This spring, in the last report of the Ohio Kxi)erimental .Station, we observe 

 that Prof, dreen asserts that the most satisfactory of the copper compounds for 

 destroying apple scab, with regard to cost, convenience and effectiveness, is the 

 dilute Bordeaux mixture. The method of prei)aring is as follows:- Dissolve 

 four pounds copper sulphate in two gallons of hot water : add sutificient water to 

 cool it. Slake four jjounds of (|uick lime, add water to make a milk of lime. 

 Pour into copper sulphate through seive to dissolve lime the better. Dilute 

 to fifty gallons. 



One advantage of this mixture is that I'aris green may be used with it, and 

 no injury to the foliage results. I'he effect should be bright, clean, healthy 

 foliage and fruit, as well as comiiarative freedom from curculio and codling moth. 

 In \\\Q Journal 0/ Myco/oi^y, Vol. \TI., No. 1. Prof, (loff, of Madison, Wis- 

 consin, reports his e.xperimenls in iSi)i in treating apple-scab. He used, chiefly, 

 copper carbonate (i) in suspension, using one ounce to 12 gallons of water, and 

 (2) diss(jlved in ammonia, one ounce to 25 gallons of water. In the latter case 

 the ounce of salt was first dissolved in a quart of ammonia. 



