1916] ECOlSrOMIC ZOOLOGY — ENTOMOLOGY. 51 



considerably delay, if not stop, the progress of the disease. The use of carbon 

 bisulphid is to be tested in connection with this disease. The first precaution, 

 the destruction of the trees by fire, is said to be rendered easy by tlie inflam- 

 mable nature of the wood. 



As no case of the disease on sour orange has been noted, it is thought that 

 this apparent immunity, if confirmed, may prove to be of great importance. A 

 system of isolation and drainage is shown to have been effective in the one 

 instance in which it was given a thorough trial, as the trees looked well and 

 dying in patches was entirely prevented. 



The pink disease of lime branches due to Corticium Ulacino-fiiscum is said 

 to exist on some estates. While it is not yet sufficiently abundant to possess 

 much economic importance, destruction of diseased branches is advised. 



Diseases of tulip and hyacinth, J. C. T. Uphof (Moller's Deut. Odrt. Ztg., 30 

 {1915), Nos. 37, pp. 295, 296; 38, pp. 306, 307).— The author suggests the trial in 

 connection with the ring disease of hyacinth and tulip of the plan which J. Rit- 

 zema Bos is said to have found successful with onions. This consists essentially 

 in the treatment of the soil about the end of March, before planting in the 

 middle of April, with lime and ammonium sulphate, ammonia being set free 

 and giving practical disinfection of the soil. 



A disease of tulip due to Sclcrotiuia tuUparum, which also frequently attacks 

 Iris hispanica, occasionally hyacinth, gladiolus, and FritUlaria imperialis, and 

 rarely narcissus, is thought to be controllable by the three-year rotation, tulips, 

 potatoes, and hyacinths. The disease of tulip caused by Botrytis parasitica is 

 most satisfactorily dealt with by removal and destruction of affected plants. 



Variation and blight resistance among walnuts, L. D. Batchelor (Mo. Bui. 

 Com. Hort. CaL, If (1915), No. 9, pp. ^28-430) .—Gbfing the results of observa- 

 tions on productivity, blight resistance, and season, the author states that this 

 disease is the greatest limiting factor for walnut production in the principal 

 walnut growing countries. It is considered that a tree which has only 10 per 

 cent of blighted nuts in an orchard which averages from 70 to 80 per cent may 

 be really more resistant than one apparently free from disease among others 

 which are only from 15 to 20 per cent blighted. Examples given show a wide 

 range of susceptibility to attack in different varieties named. 



Contributions on. the life processes of oak mildew, J. Roth (Naturw. Ztschr. 

 Forsf u. Lanclw., 13 (1915), No. 6-7, pp. 260-270).— The author presents, as sup- 

 plementary to flie work of Neger (E. S. R., 33, p. 745), his own observations 

 and experiments on oak mildew. 



The fact that this disease flourishes best in situations exposed to sunshine is 

 thought to be attributable to the influence of the sun on the host rather than 

 on the parasite, which prefers the tender, later maturing growth made by the 

 shoots in open situations. The relations of shading to parasitic growth in 

 case of other plants are also discussed. 



The publications of the Pennsylvania Chestnut Tree Blight Commission 

 (Harrisburg: State, 1915, pp. 6^1, pis. 180, figs. 7),— This is a collection of the 

 papers issued by the Pennsylvania Chestnut Tree Blight Commission, most of 

 which have been previously noted. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



The prairie dog situation in Colorado, W. L. Buenett (Off. State Ent. Colo. 

 Circ. 17 (1915), pp. 15, figs. 2). — This circular, which is intended to replace 

 Circular 8, previously noted (E. S. R., 30, p. 249), deals with the occurrence 

 of the plains prairie dog (Cynomys Itidovicianus) , the white-tailed prairie dog 

 (C. leucurus), and the Gunnison prairie dog (C. gunmsoni) in various counties 



