122 Barberry and the Black Bust of Wheat. [May, 



could grow a profitable crop. The conditions are clearly least 

 favourable within " Barberry Areas." Some of the farmers 

 have tried wheat-growing so often, with such disappointing 

 results, that they have given up the practice altogether. In 

 face of this evidence, one is forced to the conclusion that the 

 barberry is directly responsible not only for a considerable reduc- 

 tion in yield per acre but also in the amount of wheat grown, and 

 that if this factor were eliminated the yield and acreage would 

 appreciably increase. 



It may further be noted that in 1920 the Ministry of Agricul- 

 ture made a special effort to ascertain all cases of black rust 

 in the country. England as a whole was found to be remark- 

 ably free from the disease, and the common barberry is scarce. 

 A few quite small outbreaks were located, the worst case, in 

 Gloucestershire , being in immediate proximity to badly rusted 

 barberry in a hedge. Many farms in parts of Devonshire and 

 Cornwall (which counties have a similar climate to South West 

 Wales) were examined and no case of black rust was observed, 

 and during the inspection hardly a single bush of the common 

 barberry was met with. 



Losses caused by Black Rust. — In order to give some idea 

 of the damage caused by this disease, the losses suffered by a 

 farmer in Cardiganshire during the last tw T o years might be 

 quoted. On this particular farm there was, until recently, a 

 strip of barberry hedge ten yards long. In 1919 wheat was 

 grown alongside this hedge and the intensity of the disease 

 was so great that the crop only yielded eight bushels per 

 acre, and the straw wrs of little value. During 1920 wheat 

 was again grown near the barberry, but on advice the latter- 

 w T as cut down on the 20th May. This date was, unfortunately, 

 rather too late, as cluster cups were present on the barberry 

 and some of the spring spores had already been dispersed. The 

 disease made its appearance in July. Before the crop was 

 cut it was noticed that the intensity of the disease was much 

 less than in 1919, and on being threshed the crop yielded 

 sixteen bushels per acre, and the straw was much better. This 

 decrease in the severity of the attack might have been partly 

 due to the cold, w^et summer, but there is reason to believe 

 that the cutting down of the barberry also helped. In any 

 case, the farmer was quite pleased with the result, and will 

 dig up the entire plants with roots before next spring. From 

 this example it will be seen that the losses caused by the 

 disease may be very high, and in years of epidemics the crop 



