534 Journal of Agricultural Research voi. x, no. lo 



genera Juniperus, Thuja, and Cupressus. The original organism was 

 easily recovered from inoculated plants, and with red cedar the reinocu- 

 lations gave positive results. The disease symptoms in the successfully 

 inoculated plants were identical with those observed in diseased plants 

 of Juniperus spp. in the nurseries. As many of the successful inocula- 

 tions on /. virginiana were m.ade at an Illinois nursery under normal sum- 

 mer conditions, there is every reason to believe that the Phoma sp. is 

 the cause of the common red-cedar blight. The fungus has been ob- 

 tained in quantity during 1916 from nurseries in Kansas,^ Iowa, Illinois, 

 and Pennsylvania (F. P. 18147, 1814S, 18149, 25000, 25001, 25002, 25003, 

 25007).^ The Phoma sp. found associated with a serious killing of small 

 branchlets of red cedar in eastern Nebraska by Dr. Hedgcock in 1900 

 (F. P. 25006) has been found to be identical with the nursery organism 

 under consideration in this paper. 



The white cedars are not ordinarily subject to heavy parasitic loss in 

 nurseries. However, serious loss has been observed in recently trans- 

 planted Thuja orientalis T. in a nursery in the Nebraska sand hills, with 

 symptoms indicating a parasite as the cause. The ease with which 

 positive results can be secured with inoculation on all the cedars tested 

 indicates that, when any of them are grown in nurseries on a large scale 

 under climatic conditions favorable for fungus attack, trouble from 

 Phoma sp. is at least occasionally to be expected. 



A more detailed description of the disease, the parasite, and the 

 experimental evidence on which the foregoing conclusions are based, is 

 presented in the following. 



DESCRIPTION OF THE DISEASE 



In the case of /. virginiana the disease works throughout the growing 

 season in both seedling and transplant beds. Injury seldom occurs after 

 the trees are four years old. At any time before the end of the third year 

 the disease may become epidemic, often destroying entire beds. The 

 ultimate appearance of affected stock (Pi. 60, A) is much like that of 

 stock killed in other ways, as for instance, by drouth or transplanting 

 shock. However, at earlier stages a careful examination will show 

 clearly the parasitic character of the trouble. At the bases of killed 

 parts of the plants which have been dead for only a short time are found 

 regions whose color gives evidence of having been dead longer than the 

 parts beyond. These old lesions commonly are either much bleached, 

 or have a purplish or grayish cast, and are quite easily distinguished 

 from -the browner color of the recently killed parts. Frequently definite 

 lesions are found on stems which are still living or which have been only 

 recently killed. On woody stems these lesions are usually found at the 

 point of attachment of laterals which have been dead for a considerable 



1 Specimens from Professors C. A. Scott and L. E. Melchers, of the Kansas State Agricultural College. 



2 Numbers refer to collections in the OfiSce of Forest Pathology. 



