INSECTS, DISEASES AND OTHER PESTS 245 



" BRANCH ROT " (drY STEM ROt) (fUSARIUM SP.) 



This disease was reported about the same time as the 

 stem rot and has developed along with it, causing more or 

 less confusion. Observations have shown that this disease 

 is not as serious or infectious as the stem rot, although it 

 is widely scattered and almost every grower has had more 

 or less experience with it. 



Branch rot is due to a species of Fusarium, which 

 seems to work in the interior of the stem, and to cause the 

 death of the larger branches and often the main stem. The 

 stem and branches when attacked by this fungus gradually 

 wilt and cause the leaves to turn a yellowish green. This 

 yellowing or dying of the branch is rather rapid compared 

 with stem rot. In the branch rot, the stem remains firm 

 after death, although wilted and shriveled, and the bark 

 does not slough off, while the tissue beneath remains firm. 



The fungus may attack the plant at any time during 

 its life. The method by which the fungus obtains entrance 

 into the plant stem has not been entirely determined, but 

 it doubtless gains entrance through a wound or by first 

 establishing itself upon dead or inactive tissue and then 

 penetrating the living tissue. The outer leaves of the 

 cutting die soon after the cutting is put in and if these 

 leaves are at all moist, they aff"ord an excellent means of 

 entrance for the fungus into the tender tissues. The 

 plant itself may be injured in numerous ways, all of which 

 afford an opportunity for the diseased organism to enter 

 the plant. The fungus is not likely to cause injury to a 

 sound plant through soil infection. However, it is un- 

 doubtedly truly parasitic at times. 



One source of the disease is the cutting bench. It 

 attacks cuttings very easily, and in this way the disease 



