218 



Fire-Blight 

 Caused by Bacillus aniylovorits (Burr.) Trev. 



Fire-blight of quince is caused by the same bacterium as fire-blight 

 of apple and pear blight. It is usually fairly common, but is less severe on 

 quince than on the other fruits. 



Its presence in the state has been recorded from time to time, and . 

 its present known occurrence, as shown on Map 61, gives it a distribution 

 practically co-extensive with the observed cultivation of the quince. 



Injury to uncared-for trees may often be very serious, but a careful 

 pruning-out of diseased parts as they appear will prevent its spread as 

 will also the elimination of hold-over cankers. 



Powdery Mildew 

 Caused by Podosphacra oxyacanthac (DC.) De Bary 



Powdery mildew is one of two rather uncommon diseases of quince 

 in Illinois. It appears as a whitish powder covering the upper side of 

 the leaves and often extending down the leaf-stems. Under favoring 

 circumstances the mildew may result in severe leaf-injury, accompanied 

 by early and damaging leaf-fall. 



The first collection of this disease was made by G. P. Clinton in Sep- 

 tember, 1894, presumably in Champaign county. It was found in 1922 

 in Coles and Edgar counties, where severe infections were seen on a few 

 trees. Its present known distribution is small, as shown on Map 62. 



Rust 



Caused by Gyuinosporangiutu gcrtninalc (Schw.) Kern 



The rust of quince is similar in appearance to apple rust, and is 

 caused by a similar fungus. It is not known to occur commonly in Illi- 

 nois, but it is a much more serious disease than the apple rust because it 

 attacks especially the fruits and twigs. 



Quince rust was found in Hardin county in 1919. and this consti- 

 tutes the only record of its occurrence in the state. 



As with apple rust, control is to be had through the eradication of 

 near-by cedars. 



MlSCELL.\ NEGUS DiSE.ASES 



The quince, which is closely related to the apple and the pear, is sub- 

 ject to the attack of several diseases commonly found on those fruits. 

 Among these should be noted especially black rot. bitter rot, brown rot, 

 crown-gall, and bark cankers. 



None of these have so far been found on quince in Illinois with the 

 exception of a bark .canker caused by the fungus Valsa Icucostoma 

 (Pers.) Fr., which was found in 1919 in Tazewell county. 



