REPORT OF THE DEPARTMENT OF BOTANY. 



AN EXPERIMENT ON THE CONTROL OF 

 CURRANT CANE NECROSIS BY 

 SUMMER PRUNING.* 



F. C. STEWART. 

 SUMMARY. 



Necrosis, also known as wilt, blight and cane blight, is a 

 destructive disease of currants in the Hudson Valley. In its 

 most conspicuous form it is characterized by the sudden wilting 

 and dying of canes here and there through the plantation. It 

 is caused by the fungus Botryosphseria ribis which attacks the 

 canes, killing and discoloring short sections of the bark and 

 wood and thereby causing the death of all parts above the point 

 of attack. 



The behavior of the disease led to the belief that it could be 

 controlled by the systematic removal of all diseased canes at 

 intervals of three or four weeks during the spring and summer 

 of each year. This bulletin contains, chiefly, an account of an 

 experiment in which this method of treatment (called summer 

 pruning) was tested. The experiment comprised six four-row 

 plats each containing about one-fourth acre. Commencing 

 when the plants had been set one year, three plats were carefully 

 summer pruned from two to six times each year during six 

 consecutive years. The alternate three plats were used as 

 checks. The result was disappointing. At no time during the 

 experiment was there any indication that the disease had been 

 materially checked by the treatment. The infections seemed as 

 numerous and as injurious on the treated as on the untreated 

 plats and the yield of fruit was even smaller on the treated plats. 

 Accordingly, summer pruning can no longer be recommended 

 for the control of necrosis. In fact, no method of treatment can 

 be confidently recommended at present. 



* Reprint of Bulletin No. 357, February, 1913; for Popular Edition, see 



p. 725. 



[143] 



