PLATE 21. 



Walnut disease. 



Bacterial black spol of the Persian walnut (Juglans regia). more commonly known as the English walnut. Hall -developed green fruits from an 

 orchard in California, snowing the badly spotted epicarp ; spots due to Bactenum juglandis (Pierce) . Leaves and shoots are also subject to this 

 disease, which has become serious in Southern California, where large quantities of these nuts are grown for market. The attacked parts are 

 conspicuously blackened as if charred. The numerous small white spots show the location of groups of stomata. Infection takes place readily 

 through unbroken tissues. 



