223 



off the tree about a month the first appHcation of lime-sulfur spray should 

 be made three to four weeks after petal-fall. Subsequent applications 

 of this spray for the control of brown rot serve also to control scab. 



Die-back 

 Caused by P\ilsa Icncostoma (Pers.) Fr. 



Of lesser importance than the preceding diseases is die-back. It 

 occurs on the trunk and limbs but is especially a disease of the twigs. 



Infection of buds, and of twigs through wounds, occurs during the 

 growing season, and is followed by tiie death of the twigs, which, during 

 the season following, may be killed-back for four inches or more. 



The distribution of die-back of peaches in Illinois is indicated on 

 Map 69, where it is shown to occur in 11 counties widely scattered through 

 northern Illinois, and in one couniy in southern Illinois. 



Spraying does not appear to control die-back satisfactorily, though 

 it does lessen the amount of the disease. It is imjxjrtant to cut out care- 

 fully all parts showing evidence of infection. 



Minor Dise.xses 



Besides those previously noted, there occur in Illinois several jieach 

 diseases which do not materially affect either the welfare of the tree or 

 the quantity or quality of the crop. 



Leaf spot, caused by Ccrcospora circiiinscissa Sacc, has been found 

 in Champaign and Marion counties. It is not known to be widely dis- 

 tributed, or common where it does occur. 



Frosty mildew, caused by Ccrcospora pcrsica Sacc, appears as a 

 yellow leaf-spot, the under side of the spots having a frosty appearance 

 from the spore-bearing hyphae of the fungus. This disease is reported 

 to have been found in Illinois previous to 188.5, by F. S. Earle,' and it 

 was found in Union county in 1881 by A. B. Seymour. These early re- 

 ports constitute all that is known of its occurrence in this state. 



Apricot 



The apricot is not grown extensively in Illinois. It is nevertheless 

 subject to the attack of a number of diseases, several of which are the 

 same as, or similar to, those affecting peach, ])lum, and cherry, and, in 

 general, control is secured by the same means. Those known lo occur 

 on apricot in Illinois are the following: 



Scab, caused by Cladosporium carpopliiliiiii Tluiem., was found in 

 Boone and Schuyler counties in 1922. 



Bacterial shot-hole, caused by Pscudomouas pritiii E. F. .S. has 

 been found in Coles, Monroe, Hardin, Fdgar, .Massac, Saline, and Ran- 



' Ellla, J. B., and EVtrhait. B. M. Jouin. Myo. 1 : 56. 1S8B. 



