DISEASES OF PLANTS. 349 



ridia, and oospores of Phytophthora infcutans from pure cultures of the organ- 

 ism grown on a special culture medium. 



Tlie oogonla are tliick-walled with a more or less roughened or ornamental 

 external coat, and tinted more or less a chestnut brown, while the oospores are 

 moderately thick-walled, smooth, and colorless. 



It is also claimed that crosses between P. infestans and P. phaseoli, and 

 between P. infestans and P. cactorum, have been obtained by growing mixed 

 cultures of these organisms. The crosses produced oospores, some of which 

 resembled the P. mfestuns type and others the P. phaseoli or P. cactorum type. 

 However, none of the oospores germinated. 



A history of the damping-off disease of sugar beet seedlings, A. Stift 

 iOsterr. Utigar. Ztschr. Zuckcrindus. u. Lnndw., 40 (191J), Xo. 2, pp. 211-251).— 

 The author briefly reviews the opinions of prominent investigators as pub- 

 lished during the past 10 years on the probable causes of this disease and 

 methods used for its control. 



On the history of the heart or dry rot of the sugar beet, A. Stift (Osterr. 

 Vngar. Ztschr. Zuckcrindus. n. Lnndw., .',0 (1911), Xo. 2, irp. 252-273).— A 

 brief summary is given of the views of prominent investigators as published 

 during recent years on the cause of this disease, the effects of various fer- 

 tilizers on it, and methods for its control. 



[A fungus disease of the avocado], J. E. Higgins (Haicaii Sta. Rpt. 1910, 

 p. 27). — Attention is called to a fungus disease of avocados, probably caused by 

 a species of Gloeosporium. which is prevalent in many parts of the Territory 

 of Hawaii and causes nmch damage. It turns the attacked leaves a rusty, 

 brown color, and frequently causes them to fall prematurely. It also causes 

 a dying back of the twigs and branches which often terminates in the total 

 destruction of the tree. Flowers were sometimes attacked, the disease ex- 

 tending into the new wood. 



Preliminary tests are being carried out with 4 fungicides, viz, 6 : 6 : 50 Bor- 

 deaux mixture plus arsenate of lead, a resin-lime mixture consisting of 2 gal. 

 of resin lime to 48 gal. of dilute Bordeaux mixture, a 6: G: 50 self-boiled lime- 

 sulphur mixture with arsenate of lead, and a 1 : 30 commercial lime-sulphur 

 mixture with arsenate of lead. 



So far none of the sprays have produced any serious foliage injury, but it is 

 yet too early to judge of the fungicidal results. 



The Panama disease, I, II, E. Esskd (Ann. Bot. [London], 25 (1911), No. 

 98, pp. 3Ji3-361, pis. 2). — A study is reported of the characteristics and cause 

 of this banana disease. It is claimed that a species of fungus belonging to the 

 Hypocreacese, and for which the name TJ stilaginoidella muscBperda is proposed, 

 is its true cause. 



The author claims to have isolated the fungus, and descriptions are given 

 of various spore forms, sclerotia, conidia, several kinds of chlamydospores, 

 mycocecidia, etc. Two species of bacteria {Micrococcus sulfureus and Bac- 

 terium fluorescens) were found associated with the fungus. 



In the second paper the author gives the results of further studies on the 

 organism and of inoculating experiments with the organism and with the 2 

 associated bacteria. The so-called sclerotium noted in the first paper is here 

 called pegmatium, and is defined as a structure which arises from well- 

 nourished hyphse and hardens into gristly or gummy bodies having the power 

 to regenerate the fungus by means of chlamydospores or by mycelia arising 

 from them without the interposition of a spore st^ge. 



The reproductive organs are given as ascospores (none of which have yet 

 been found), conidia, chlamydospores, and oidia. Two enzyms were found to 

 be secreted by the fungus, one, probably cytase, capable of dissolving the cell 



