Arizona Agricultural Exi'Krimi:nt Station 431 



English walnuts, nine varieties of Japanese persimmons, thirteen 

 varieties of Hanson's hybrid plums, in addition to plants of Chinese 

 jujube, Persian, Downing and Hick's everbearing mulberries, Caro- 

 lina evergreen cherries, Virginia persimmons, buffalo berries, 

 Feijoa sellozvana, Pinits halcpensis, Fittospontm phillyracoides, Plio- 

 t'liia scrnilata, Hctcroiiiclcs arbiitifolia, and Carpcnteria californica. 



PLANT DISEASE INQUIRIES 



An unsually large number of inquiries were received during 

 the past year relative to plant diseases. This was due to a desire 

 on the part of planters to increase crop yields and prevent waste 

 as far as possible. A root-rot of the white sweet clover was sent 

 in from the Sulphur Spring Valley for examination. Professor 

 Brown identified this as a root-rot caused by the fungus, Ozoninm 

 oynnivermn. Though not common in our State, this is a common 

 root-rot of alfalfa and cotton in Texas. 



Potato plants affected with early potato blight were sent in 

 from near Willcox, Arizona. When the plants were examined the 

 disease had progressed too far to secure practical results by spray- 

 ing with Bordeaux mixture. 



The well known sore-shin disease of cotton was recognized by 

 Professor Brown on cotton seedling i)lanls from Mesa, Arizona. 

 This is a damping oft disease of )-oung cotton plants caused by a 

 fungus, Corticimn I'aiium var. sohnii. This was formerly known in 

 its sterile form as a species of Rhi:::och>in\t. and is a widespread dis- 

 ease attacking many crops. 



The angular leaf s])ot disease of cotton was foimd on cotton 

 plants growing at Alesa, Arizona. This disease is common in cot- 

 ton growing countries and is not considered serious. 



Tomato wilt, as usual, was bad during July and August. It 

 was reported from many localities in southern Arizona. The com- 

 mon root-rot of alfalfa and deciduous trees also w^as serious in the 

 southern and central parts of the state. 



The dry-rot disease of the potato caused some damage at Flag- 

 staff, Arizona. This is a serious disease in many potato growing 

 communities. It is caused by a species of pHsariiim which lives in 

 the soil for several years, and hence careful crop rotation is essen- 

 tial in combating it. It is recommended that a five-year crop rota- 

 tion be used in infected fields. The disease attacks both the tubers 

 and the tops of growing plants ; also, it causes dry-rot in potatoes 



