198 



Bulletin 252. 



sulfate 2 lbs. to 50 gals, water is also efifective. The addition of lime, however, 

 makes it easj' to tell where the spray has been applied. 



This often proves troublesome in wet seasons and particularly 



Black-spot in damp or sheltered situations. While this disease attacks the 



or scab. twigs and leaves it is most conspicuous and injurious on the 



fruit where it appears as dark spots or blotches. In severe 

 attack, the fruit cracks. In the treatment of 

 this disease, it is of prime importance to secure 

 a free circulation of air about the fruit. Ac- 

 complish this by avoiding low sites, by pruning 

 and by removal of windbreaks. Spray as for 

 leaf-cnrl and follow with two applications of 

 potassium sulfide, i oz. to 3 gals., the first being 

 made soon after the fruit is set and the second 

 when the fruit is half grown. The self-cooked 

 lime-sulfur wash has been shown to be very 

 effective against this disease. See brown rot. 

 (Fig. 171.) '^^^^^^^i^ - / 



is a so-called ''physiological 

 Yellows disease." Cause unknown. 



Contagious and quite serious 

 in some localities. Known by the premature pjg j^j Black-spot on peach. 

 ripening of the fruit, by red streaks and spots 



in the fruit flesh and by the peculiar clusters of sickly, yellowish shoots that 

 appear on the limbs here and there. Eradication is the only means of control. 

 Dig out and burn diseased trees as soon as discovered. 



PEAR. 



This is the same as fire blight of apple but it is more destructive 

 Fire-blight, to pears. It kills the twigs and branches on which the leaves 



suddenly blacken and die but do 

 not fall. It also produces cankers on the trunk and 

 large limbs. Prune out blighted branches as soon as 

 discovered, cutting 6 to 8 inches below the lowest 

 evidences of the disease. Clean out limb and body 

 cankers as described for fire blight on apple trees. 

 Disinfect all large wounds with corrosive sublimate 

 solution, I to 1000, and cover with coat of paint. 

 See Cornell Bulletin 236. Avoid forcing a rapid, 

 succulent growth of wood. Plant the varieties least 

 affected. 



is a fungous disease very similar to 

 Scab apple scab but it is not the same, 



however. It is very destructive to 

 some varieties, as for example, Flemish Beauty and 

 Scckel. Spray three times with Bordeaux as for 

 apple scab. See Cornell Bulletin 145 and Geneva 

 Bulletins 67 and 84. (Fig. 172.) pig_ 172. Pear-scab. 



