21 fi 



among 9 counties. Practically 100 per cent of the trees were infected 

 with blight, which involved an average of 43.1 per cent of the branches. 

 No satisfactory means of control is known but. as in the case of 

 apple fire-blight, cutting out diseased twigs in young orchards and elimi- 

 nating hold-over cankers in old orchards are helpful. .\ certain amount 

 of freedom may be secured by planting relatively resistant varieties, such 

 as Kieffer, Duchess, Koonce, Anjou, Seckel, Vermont Beauty. Garber, and 

 Lincoln. However, even these varieties are so susceptible to attack that 

 only the closest attention to the orchard will prevent extremely serious 

 losses. 



Le.\f Blight 



Caused by Fabraca maculata (Lev.) Atk. 



This disease of the pear is second in importance to pear blight. 

 Though common, it is not often sufficiently abundant to cause serious 

 damage. It is limited for the most part to the leaves, where it causes 

 circular spots, at first carmine-red, later developing a brown center bear- 

 ing a single black spot. Similar spots are occasionally produced on the 

 fruit and on the twigs. Severe infections result in serious defoliation. 



As a rule the loss caused bv this disease is small. Epidemics are 

 rare, and fruit is seldom infected. The disease should not be confused, 

 as the name indicates that it might be. with pear blight. 



The earliest known occurrence of it in Illinois was in L'nion county 

 in 1912. Its present known distribution is shown on Map 5fi. 



The prevalence of leaf blight in orchards and its importance as a 

 disease w-as illustrated by examinations made in 12 orchards in 1922. 

 Among some 400 trees 33 per cent were infected and 49 per cent of the 

 leaves were diseased. 



Control of this disease is obtained by the use of the usual sprays. 



Scab 

 Caused by I'cntiiria pyr'ina Aderh. 



Scab is not of common occurrence in Illinois. In appearance it is 

 similar to the scab of ap]iles and is caused by a similar fungus. 



Its known occurrence in the state is shown on Map .37, which indi- 

 cates a wide' distribution. It has not appeared commonly, however, in 

 the important pear-producing regions. The S counties in which it is 

 known to occur are widely separated but, with the exception of Jackson 

 county, lie outside of the areas of intensive culture. 



Injury by this disease to leaves and fruit, as in the case of apple, con- 

 stitutes its chief menace. Control is accomplished with the usual sprays. 



Black Rot 



Caused by Physalospora cydoniac Arn. 



This disease is identical with the black rot of apples but it is not of 

 such common occurrence, nor apparently so serious, on the pear. 



