266 MANUAL OF FRUIT DISEASES 



BRUNISSURE 

 Cause not definitely determined 



Brunissure is a name taken from the French which means a 

 browning. The term refers to the effects on the foliage. The 

 first manifestation of the disease is the appearance of irregular 

 brownish spots on the upper surface. The epidermal cells 

 finally slough off, exposing the underlying parenchyma, and 

 numerous white spots appear on the dark background. Ulti- 

 mately the browning involves the tissues through the leaf and 

 the lower surface is reached. The trouble shows from July to 

 November. As a result of the affection the berries ripen poorly, 

 their sugar content is reduced, the vines fail to mature, and black 

 zones appear in the wood as far down as the roots. 



The disease is known in France, where it appeared in the 

 autumn of 1892. It is also known in Italy and elsewhere 

 abroad. Typical cases have been observed in the United States, 

 notably in California. It is destructive only in isolated cases. 

 The disease is thought to affect other plants such as the lily, 

 tobacco, tomato and rose. 



The cause of brunissure has not been positively determined. 

 At first it was thought to be due to scale insects, then to a slime 

 mold, Plasmodiophora Vitis (Pseudocommis Vitis). Unfavor- 

 able soil and weather conditions have been suggested as possible 

 causes. It is generally agreed at present that the disease is 

 non-parasitic, but this helps but little in disclosing the true 

 cause. Control measures are unknown. 



REFERENCE 



Woods, A. F. Brunissure of the vine and other plants. Science, n. ser. 

 9 : 508-510. 1899. 



