458 EXPERIMENT STATION RECORD. [Vol.87 



[Lophodermium pinastri and Pliacidium infestans on pine], T. Lagerbebg 

 (Statens Skogsfors. Ami. [Sicedeti], Flyghl. 5 (1915). pp. 10. figs. 6).— This is a 

 brief discussion of L. pinastri, which causes a pine needle cast, and P. infestans, 

 which is said to l^ill out young pines in the nursery. 



The pine blister disease (Amer. Forestry, 22 {1916), No. 276. pp. 748-750, 

 figs. 2). — It is stated that the white pine blister, or canker, has made steady 

 progress in the portions of New England from which it has been previously 

 reported, and that what are thought to be the areas of new infection have 

 been discovered recently, so that the situation is constantly becoming more 

 serious. 



Recent study of pod disease and canker in Hevea. A. A. L. Rvtgers 

 (Meded. Adv. Alg. Ver. Rubberplantcrs Oostkust S^umatra, No. 5 {1916). pp. 

 63-66). — The author, having carried on for some time a study of Hevea canker 

 (E. S. R.. 32, p. 242). which is claimed to be caused by Phytophthora faheri, 

 states that slightly infected trees recovered in nearly every case, and trees 

 severely infected in a number of cases. This form of the fungus is thought to 

 be identical with that causing a disea.se of cacao and other plants. Infection 

 experiments with Hevea fruits succeeded, causing a rot thereof in several 

 instances. 



A root disease of plantation rubber in Malaya due to Poria hypolaterita. 

 W. N. C. Belgrave {Agr. Bui. Fed. Malay f^taies. 4 {1916), No. 11. pp. S47- 

 S50). — This is a preliminary report on investigations continued since 1015. 

 and still in progre.ss, on a wet foot rot of mature rubber trees in Malaya, which 

 is described as due to P. hypolaterita. 



The disease is spread by root contact. Its progress being slow and insidious, 

 the trees yielding latex until they are very far gone. The fungus is suspected 

 to be too common in jungle lands to justify the use of isolation trenches except, 

 possibly, to Isolate the larger-inforted areas. This may be done with deep 

 drains, the trees being then tapped until they die. whi<h may require at least 

 five years. 



Some suggestions on the control of mistletoe in the National forests of the 

 Northwest. .1. R. Weir {Forestry Quart., 14 {1916), No. 4. pp. 567-.'i77).—Thif^ 

 article, while relating mainly to forestry measures and methods, notes also the 

 fact that mistletoe brooms, and eventually the uninfected parts of the tree, 

 cea.se to produce seed, which may be a serious matter in view of the trying 

 conditions related to reproduction and survival of forest growths. It is stated 

 also that the false mistletoes (Razoumofskya) are of much greater importance 

 In the western than in the eastern portions of the United States, practically 

 every western conifer being attacked by at least one of the.se parasites, which 

 may be inconspicuous but usually show a greater degree of parasitism than 

 do the Phoradendrons. 



The author reports briefly on a .study of the more minute details of the 

 anatomy of the sinkers and horizontal root system of the para.site, stating that 

 the phloem of the host is found to be, in some species, in direct union with the 

 absorbing cells of the parasite. The weakening of heavily infesteil young trees, 

 and other facts noted, are con.sidered as proof of a heavy drain on the host by 

 the parasite. The fact that if a seed of one of these species falls on a plant 

 other than an accustomed host it will exhaust its energy in producing a long 

 hypocotyl without penetrating the substratum is considered proof of a special 

 adaptation of the parasite to particular types of cell structure or chemical 

 constitution of the hosts. This fact may become important in connection with 

 the planting of mixed forests. Mistletoe attacks hosts of all ages, and trees 

 attacked when young are apt to be otherwise diseased. 



