PROTECTING PLANTS 211 
the fruit cracks. In the treatment of this disease it is of prime im- 
portance to secure a free circulation of air about the fruit. Accomplish 
this by avoiding low sites, by pruning, and by removal of windbreaks. 
Spray as for brown-rot, with lime-sulfur, 8-8-50. 
Yellows is a so-called ‘“ physiological disease.” Cause unknown. 
Contagious, and serious in some localities. Known by the premature 
ripening of the fruit, by red streaks and spots in the flesh, and by the 
peculiar clusters of sickly, yellowish shoots that appear on the limbs 
here and there (Fig. 215). Dig out and burn diseased trees as soon as 
discovered. 
Pear diseases. — Fire-blight 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 in. below the lowest evidences of 
the disease. Clean out limb and body cankers. Disinfect all large 
wounds with corrosive sublimate solution, 1 to 1000, and cover with 
coat of paint. Avoid forcing a rapid, succulent growth. Plant the 
varieties least affected. 
Pear scab is very similar to apple scab. It is very destructive to 
some varieties, as, for example, Flemish Beauty and Seckel. Spray 
three times with lime-sulfur, 1-50, or bordeaux, 3-3-50, following the 
general methods employed for apple scab. 
Plum and cherry diseases. — Black-knot is a fungous disease. The 
spores of the fungus are carried from tree to tree by the wind and thus 
spread the infection. Cut out and burn all knots as soon as discovered. 
See that the knots are removed from all plum and cherry trees in the 
neighborhood. 
Leaf-spot is a disease in which the leaves become covered with red- 
dish or brown spots and fall prematurely (Fig. 211) ; badly affected trees 
winterkill. Often, the dead spots drop out, leaving clear-cut holes. 
Bordeaux, 5-5-50, or lime-sulfur, 1-40. For cherries, four applica- 
tions: first, just before blossoms open; second, when fruit is free from 
calyx; third, two ‘weeks later; fourth, two weeks after third. In 
plums it may be controlled by two or three applications of bordeaux, 
3-3-50, or self-boiled lime-sulfur. Make the first one about ten days 
after the blossoms fall and the others at intervals of about three weeks. 
This applies to European varieties. Japan plums should not be 
sprayed with bordeaux. ; 
