220 



The known distribution of brown rot of peaches in Illinois, is as 

 shown on Map 65. It appears to be general over the southern tip of the 

 state, including the counties important in commercial peach-production. 

 Northward, distribution is more scattered, covering in a general way the 

 territory between the Illinois and Mississippi Rivers. Toward the east, 

 an irregular distribution occurs in six counties which lie along the tribu- 

 taries of the Illinois and Wabash Rivers. It is probable that brown rot 

 is even more wide-spread than has been recorded. 



Estimates of crop reductions from brown rot for 191T-1923, and 

 reproduced in Table 40, vary from none in 1918 to 12 per cent in 1917, 

 equivalent to 50,000 bushels valued at $97,000. These amounts represent 

 the loss in orchards, and do not include the tremendous losses which often 

 occur between the harvesting of the crop and its ultimate disposal to the 

 consumer. 



An examination in 1922 of 32 orchards of varying size, scattered 

 uniformly through 24 counties, indicated an average infection of 17 per 

 cent of the trees and nearly 15 per cent of the fruit. Field notes of 

 1923 show that in 9 orchards the average of infected trees was slightly 

 more than 62 per cent, with infected fruit averaging 26 per cent. 



Control of brown rot is often difficult, since an outbreak may occur 

 whenever sufficiently wet weather comes on. Twig and blossom blight 

 is especially to be expected in damp springs and serious fruit infection 

 may appear any time during the season during damp warm weather. The 

 application of proper sprays should therefore be made with particular 

 reference to predicted weather conditions. Assiduous adherence to such 

 a schedule may reasonably be expected to do away with the considerable 

 losses which might otherwise occur. 



Leaf-curl 

 Caused by Exoasciis deforni<ins (Berk.) Fckl. 



This disease is probably second to brown rot in destructiveness to 

 peaches. It is confined to the current year's growth, aflfecting leaves, 

 twigs, and blossoms. The leaves appear thickened along the veins, caus- 

 ing the blade to become folded, wrinkled, and puffed, and the edges to 

 curl in on the under side. Ultimately the leaves turn yellow and fall 

 from the tree. 



The early history of this disease in Illinois is not known. It was 

 reported by Burrill to have occurred in Champaign county in 1890 and 

 in Champaign and Livingston counties in 1911. The extent of its prev- 

 alence as now known is shown on Map 66, which indicates its occurrence 

 in 62 of the 102 counties of the state. The area of most common occur- 

 rence lies along the northern boundary of the region of commercial peach- 

 production and this fact lends color to the belief that this is a northern 

 disease. It should be remembered, however, that leaf-curl is very readily 

 controlled and that its apparent common distribution on the northern edge 

 of the commercial district may result from a more perfect control south- 



