550 EXPEEIMENT STATION EECOED. 



The known distribution of Pythiacystis citrophthora and its probable 

 relation to mal di gomma of citrus, H. S. Fawcett {Phytopathology, 5 {1915), 

 No. 1, pp. 66, 67). — In a previous publication tbe author reported this fungus 

 as being the causal agent of one form of lemon gummosis in California (E. S. 

 U., 30, p. 51). Since that time the fungus has been isolated from diseased bark 

 from nearly all the important citrus growing localities of California. 



In June, 1913, it was isolated from diseased bark of orange trees that ap- 

 peared to be affected with typical mal di gomma, or foot rot, as it is known in 

 California. Inoculations and cultures of this fungus were made in large crown 

 roots of old orange trees, and in nine months they developed diseased areas 

 which resembled the beginning stages of mal di gomma. The orange bark is 

 said to be somewhat more resistant than lemon bark and reacts somewhat dif- 

 ferently toward the fungus. This, it is believed, explains the difference in ap- 

 pearance of mal di gomma and lemon gummosis in California. 



In addition to the occurrence of this fungus in California, the author reports 

 having observed it in Florida, Cuba, and the Isle of Pines, and claims to have 

 record of it in southern Europe and in Brazil. 



The citrus root nematode (Tylenchulus semipenetrans) in Florida, E. 

 Nelson {Phytopathology, 5 {1915), No. 1, pp. 12, 13). — The author reports hav- 

 ing examined 35 orange trees, 5 of which had healthy foliage and showed no 

 infestation with nematodes. The leaves of the remaining 30 were affected with 

 a form of chlorosis known as frenching. Twelve of the 30 affected trees showed 

 the presence of root nematodes, but the remaining 18 showed no infestation. 



The author believes that further investigations and experiments are necessary 

 before any conclusions can be drawn as to the connection of this nematode with 

 the frenchiug of citrus trees. 



Storm and drought injury to foliage of ornamental trees, C. Haetley and 

 T. C. Merrill {Phytopathology, 5 {1915), No. 1, pp. 20-29, figs. 3).— Detailed 

 observations are given showing the effect of drought and storms in the District 

 of Columbia and several places in Pennsylvania and New Jersey. 



In the District of Columbia the June and July rainfall in 1913 was much be- 

 low normal and this period was followed on July 30 by a hail storm, heavy rain, 

 and wind of high velocity. It is said that at least 25 per cent of all Norway 

 maple trees in the District of Columbia were noticeably affected by the drought. 

 Other maples suffered somewhat, but less severely, and drought injury was also 

 noticed on oaks and other trees. The effect of the storm mentioned above was 

 quite pronounced on many different kinds of trees, but so far as observed the 

 drought preceding the storm was not in any way responsible for the storm in- 

 jury. The leaves of the sugar maple were found most susceptible to injury by 

 the high velocity of the storm. The damage was similar to that produced by 

 drought in that the margins of the leaf and the area between the veins were 

 affected, but the material difference between the two forms of injury is that 

 drought injury is more closely confined to the leaf margins, while storm injury 

 tends to affect areas situated between the veins as well. 



New hosts for some forest tree fungi, J. R. Weir {Phytopathology, 5 {1915), 

 No. 1, pp. 11, 12). — The author reports the occurrence of Herpotrichia nigra. 

 or its related form, Neopeckia coulteri, on the giant western red cedar, grand 

 fir, western yew, and x-ed or Douglas fir. It is also reported on the western 

 white pine, the Engelmann spruce, mountain hemlock, lodgepole pine, white 

 barked pine, and alpine fir. Fomes laricis is reported for the first time on 

 Pinus monticola, AMes grandis, and Tsuga mertensiana. F. igniarius was found 

 on Rhamnvs pursJiiana and Samhucus glauca— Armillaria mellea is reported as 

 attacking Taxus hrevifoUa, and Polyporus lucidus was found growing on the 

 mountain hemlock. The mountain hemlock has in many places been seriously 



