MARKET DISEASES OF FRUITS AND VEGETABLES 65 



QUINCES 

 Black Rot 



(See Apples, Black Rot, p. 14.) 



Black Spot 



(Fabraea maculata Atk.) 



The black spot fungus causes leaf spotting on pear and quince, 

 which is sometimes serious on nursery stock. If this disease is not 

 controlled the causal fungus may spread to fruit and cause serious 

 spotting (pi. 11, B, C). The disease is most common east of the 

 Mississippi River and has not been reported on fruit grown in 

 California and the Northwest. It does not develop or spread in 

 storage or transit and is not commonly followed by rot of any kind. 



Black spot manifests itself as black, circular, sunken areas 

 ranging in diameter from about y 16 to % inch and occurring 

 on any part of a fruit. In the early stage the spots are usually 

 surrounded by red rings, which may darken later. The surface 

 may crack like that of spots affected with pear scab. 



Commercial control of the disease can be obtained by spraying 

 in accordance with recommendations of the local agricultural 

 experiment station. 



(See 59, 65.) 



Blue Mold Rot 

 (See Apples, Blue Mold Rot, p. 16.) 



Brown Rot 

 (See Apples, Brown Rot, p. 20.) 



Oriental Fruit Moth Injury 



(Grapholitha molesta (Busck) ) 



Quinces are often found at harvesttime to be completely honey- 

 combed with tunnels caused by the oriental fruit moth (pi. 15, 

 C). Although this insect has received attention chiefly as a peach 

 pest, it has a particular preference for quince. 



The New York State Agricultural Experiment Station has 

 found that the oriental fruit moth can be controlled on quince by 

 repeated applications of lead arsenate, of nicotine sulfate and 

 summer oil, or of nicotine bentonite. The lead arsenate program 

 results in residues that should be removed before the fruit is 

 marketed. DDT, which has given good control of the oriental 

 fruit moth on peach, should be effective against it on quince. 



(See 320 



