ZOOLOCIY AND I'.OTANY, MICUOSCOl'Y, ETC. 71 



"Black Neck," or Wilt Disease of Asters. — W. Robinson {Ann. 

 App. JlioL, r.)15, 2, l^;")-;^?, 2 pis.) found that this fungus was due to a 

 species of Fhytophthora, possibly a physiological form of /\ omnivora. 

 The sporangia are peculiar in that the stalk grows through the sporan- 

 gium after the discharge of the zoospores and forms a second and even 

 a third. No sexual organs were observed. A. L. S. 



Silver-leaf Disease. — T. Smolak {Ann. App. Biol., 1915,2, ISS-fjI, 

 11) figs.) investigated the cytology of leaves attacked by this disease. 

 He describes the changes induced, resembling those found in gall-tissue. 

 He does not consider that the disease is in all cases due to Stermm 

 pHr2')nreum, nor does he think the silvering is caused by an enzyme ; 

 more probably a toxin is secreted in the leaves, which causes the changes 

 which he describes. A. L. S. 



Tomato-fruit Rots. — These fruit-rots, according to .1. RosKNP.AU.'vf 

 ( Phylopatholoijij , i;)18, 8, 572-81, 1 pi.), do not originate in transit as was 

 supposed, but have been traced to Held infection, though the trouble 

 may spread in transit. Over-ripeness of the fruit is favourable to the 

 development of the rot fungi. He finds three types of rot : (1) Buckeye 

 Hot {Fhytophthorti terrestria), which can spread to adjacent uninjured 

 fruit ; (2) Soil Rot {Rhizoctonia sp.). White Hot {Sclerotium Rolfau), and 

 lieak {Rkizopuf< sp.), (the fungi of this type infect through the stem end 

 or through some break in the skin) ; (a) Nail-head Spot {Macrosporium 

 Solani), Black ^^ot {Phoma dedructiva), and Anthracnose {Golletotrichvm 

 phomoides) — these do not affect healthy adjacent fruit. A. L. S. 



Some Potential Parasites of the Potato Tuber. — T'liere are a 

 number of saprophytic i'ungi, niaiidy Hyphomycetes, that are fi-efjueutly 

 found on potatoes in storage. M. Siiapovalov {Phytopatholoyy, 1919, 

 9, 36-42, 2 pis., 2 figs.) has demonstrated that these fungi may be- 

 come parasitic and cause considerable damage. The fungi under 

 observation were FenicilUum oxalicam, Asperyillus niyer, and (Jlono- 

 stachys araucaria var. r.oma. The author compares the rot caused by 

 these moulds with the damage done l)y Fmarium radicicola, a serious 

 wound-parasite of the potato. The lesions made by Asperyillufi niyer 

 were almost as deep as those made by the Fmarium. in the same time ; 

 those by the FenicilUum a little less so, while those by GlomMachys lagged 

 some way behind. He found, however, that the Asperyillus was less 

 likely to cause infection than the Fenicillium. A. fi. S, 



Diseases of Yams. — The yam affected, iJiscorea prehensilis, was 

 collected in Nigeria and sent to Kew for examination. E. M. Wake- 

 field {Kew BiUL, 1918, 199-201, 1 pi.) found that the cause of the 

 disease was a fungus belonging to tiie geims y>'a///w'.s7'o;?.s-<.s-(Dothideacete). 

 It attacks isolated branches of the yam-vine, blackening and destroying 

 them ; the internodes are shortened and the leaves dwarfed. A diagnosis 

 of the fungus B. Dioscorese is given. A. L. S. 



