200 



thirteen galloiiH ot' cold water. Soak the seed potatoes in 

 this solnti(>ii 'for ail hour and a half, then dry, cut and phiiifc 

 as usual, 'f h'6 tfe.-ited potatoes should of course all be 

 planted and ucjb used for other purposes as they are poisoned 

 by the treabineiit. When scabby potatoes are fed to stock' 

 it is unsafe to hse the manure for fertilizinp; potatoes as the 

 scab fungus propagates lu the manure and is thus taken to 

 the field. On this account chemical fertili/evs are usually 

 preferred by potato growers. 



LEAF-si'of 01'' I'OTATOEs OK Maohospoiuum uisease. — Po- 

 tato foliage is often observed to be covered by rounded 

 brown or arid spots. At first these spots are marked by 

 concentric rings or /ones of a darker color, but at length the 

 dried })ortiou of the leaf often In-eaks out and falls away. 

 This spotting may begin soon after the plants are up. If 

 there is but little of it no great damage is done, but when 

 abundant it destroys so much of the leaf surface that the 

 nutrition of the plant is deranged and the tubers are few 

 and small. In extreme eases the leaves fall and the plant 

 dies prematurely without forming tubers at all. It is a wide 

 spread disease and frequently occasions much damage. 

 Fortunately it can be quite effectuallj^ controlled by careful 

 spraying with Bordeaux mixture. The first spraying should 

 be given soon after the plants are up and should be repeated 

 three or fourfcimes, at intervals of ten days or two Aveeks. 

 It must be remembered that this treatment, like most others, 

 is preventive not curative. The Bordeaux mixture serves to 

 protect the f<:>liage from attack; it does not cure the spots 

 already formed, hence the importance of beginning the 

 'treatment early. To be successful we must keep ahead of 

 the disease. 'Fortunately the labor of spraying will not be 

 lost even if the disease does not appear, for in some way, 

 not understt^od; the Bordeaux mixture seems to slightly in- 

 crense the yiekl besides preventing the disease. 



If potato be^^tles appear, Paris green may be mixed 

 with the Bordeaiix mixture as indicated elsewhere, and 

 both enemies' can be combatted by the one application. 



