3IO PLANT DISEASES 



to; and to prevent a recurrence of the disease from conidia 

 present in the soil, the surface soil should be removed and 

 fresh soil added, with a layer of quicklime on the surface. 

 Massee, Kew Bulletin, 1899, p. i, i pi. 



PLUM SCAB 



(Cladosporium carpophilum, Thiimen.) 



This disease has received the name of 'scab' in the 

 United States. It attacks the fruit of cultivated plums, 

 cherries, and almonds. On half-grown fruit the fungus 

 forms greyish or olive-brown spots, which extend radially ; 

 when numerous the fruit shrivels, and often cracks. 



Preventive Means. — Bordeaux mixture has been sug- 

 gested for checking the disease ; it should contain a little 

 treacle or soap to secure adhesion. Spraying should cease 

 when the fruit commences to ripen. 



Pammel, loiva Agric. Coll. Expt. Station, Bull. No. 23, 

 p. 918, 2 figs. (1894). 



LEMON AND ORANGE SCAB 



{^Cladosporium citri — pro tern.) 



This disease, so fully described and illustrated by 

 Swingle and Webber, proves very injurious to lemon and 

 orange trees in Florida and Louisiana. The disease is 

 indicated by the presence of numerous small warts or 

 excrescences on the leaves and fruit. When the fruit is 

 attacked quite young, the warts are often numerous, and 

 measure up to ;|-inch high and across, although often 

 smaller. The disease is caused by a minute fungus, which 

 covers the warts with a delicate mould, grey at first, then 



