221 



ward and also from the presence of an increasing number of private 

 plantings northward in which disease-control is not practiced. 



The abundance and severity of leaf-curl on peach may be illustrated 

 by notes from the observations made in 1933. 



"In Pike county, in a one-acre block of Lemon Clings all were in- 

 fected and suffering considerable defoliation. A ten-acre tract of Belle 

 of Georgia and Champion showed a large amount of infection, with de- 

 foliation of 10 to 15 per cent on the Belle of Georgia. In Edwards 

 county a one-acre orchard of Elbertas showed 10 per cent of the leaves 

 infected, and a two-acre tract of Hales 50 per cent of the leaves infected." 



The use of resistant varieties is helpful in controlling this disease, 

 At least, an effort should be made to avoid the planting of susceptible 

 varieties, such as Lemon Cling and Belle of Georgia. Less susceptible, 

 but still remarkably subject to infection, are the Elberta, the Hale, and 

 the Carmen. 



Further control is readily accomplished in most cases by the appli- 

 cation of the customary dormant lime-sulfur spray, with especial atten- 

 tion given to thoroughly coating the buds. 



Bacterial Shot-hole 

 Caused by Pseudomonas pruni E. F. S. 



This constitutes the third important disease of peaches in Illinois, 

 It affects both the fruit and twigs, but is especially noticeable on the leaves, 

 where it appears as small spots, at first light colored but later becoming 

 darker and eventually turning brown. Ultimately the spots separate from 

 the leaves and fall out, giving the characteristic shot-hole appearance. 

 Serious infection causes defoliation. On twigs spots are formed which 

 turn dark and may kill the twig. Small purple spots, usually not more 

 than 1/1 (J of an inch in diameter, are produced on the fruit, the skin 

 cracks, the appearance of the fruit is marred, and it is made especially 

 susceptible to attack by brown rot. 



The history of the bacterial shot-hole as a serious peach disease in 

 Illinois dates back only to 1!)15. According to Anderson' it was observed 

 near Centralia in litT-i. Since that time it has been widely observed, and 

 is a disease needing careful attention for its control. 



Its distribution as indicated by specimens collected in 1922 and 1923 

 is shown on Map GT, which indicates its occurrence in 82 counties 



There appears to be no marked fluctuation in its severity from year 

 to year. A crop reduction of 2 per cent was estimated for 1922 and 1923. 

 In the first year this amounted to 22,000 bushels valued at $38,000 and 

 in the .second year to 14,000 bushels valued at $3(),00(). 



Infection is very general where it has been observed to occur. In 

 20 orchards examined during 1923 in 12 representative counties and 

 covering 1002 acres, 92.2 per cent of the trees were affected by this dis- 



> Diseases of Illinois Fruits. HI. Acr. lOxpi-r. Sta. Circ. 211: 90. 1920. 



