211 



estimates an average annual loss of 1 per cent of the apple crop, the valu- 

 ation ranging from $25,000 to $30,000. For the 1922 and 1923 seasons 

 estimated losses of 1 per cent were equivalent to 98,000 bushels valued 

 at $102,000 and 74,000 bushels valued at $85,000. 



The seriousness of this disease in our orchards is illustrated by the 

 results, shown in Table 3C, of an examination of 21 Ben Davis orchards 

 distributed among 14 representative counties. The examinations were 

 made during the summers of 1922 and 1923 and showed that 21.8 per 

 cent of the trees were diseased. 



How uncared-for infections may result was shown in 1922 by a 

 special survey, with careful examination of trees in three Wayne county 

 orchards. In orchard Number 1, which was about 50 years old, there 

 were 400 trees, of which 95 per cent were diseased with blister canker; 

 100 trees had been killed and were being taken out; 100 other trees were 

 dead or so nearly dead as to bear no crop; 150 trees were so severely 

 diseased as to have their crop materially reduced ; and only 50 trees were 

 still in good bearing. 



In orchard Number 2, which had 150 trees, 100 were dead or nearly 

 so, and the remaining 50 were badly diseased and bearing small crops of 

 inferior fruit. 



Orchard Number 3 had about 300 trees, many of which were dead 

 and many others dying. More than 80 per cent of the trees were dis- 

 eased with blister canker, and the crop was poor in quantitv and of in- 

 ferior quality. 



Control of this disease consists in carefully pruning out all infection 

 as soon as it becomes apparent, and in the use, so far as practicable, of 

 varieties relatively resistant to the disease. 



Bitter Rot 



Caused by Glonwrella cingnlata (Stonem.) S. & v. S. 



Bitter rot, a disease which affects the fruit especially, though often 

 causing stem cankers, is ajiparently limited to the extreme southern part 

 of the state. 



The past history of this disease in Illinois is not well known except 

 for the serious outbreak of 1901 and 1902. .\t that time the disease was 

 studied by Burrill, Blair, Clinton, von Schrenk, and Spaulding, and the 

 loss in the state estimated at a very large figure. During subsequent 

 vears the disease a])pears to have become less and less severe until 1923, 

 when another outbreak occurred. Bitter rot was seen in the counties 

 indicated on Map 48, and the crop reduction due to its presence was 

 estimated at 1 per cent or 74,000 bushels valued at $85,000. 



Control of bitter rot demands careful attention to the application of 

 sprays before the disease appears. When it does appear sprays should 

 be supplemented by careful and thorou.gh hand-picking of diseased fruits. 

 Since the disease overwinters in the twig cankers, these should be cut out 

 of the trees wherever they are found. 



