344 EXPERIMENT STATIOlSr EECORD. 



abeyance by atiuospberic (•oiiditions. When a number of warm, damp days of 

 dull weather intervene the funyus, already present in the tissues, develops with 

 great rapidity. It is believed that the two diseases will not occur in an 

 aggressive form when the climatic conditions are unfavorable to their develop- 

 ment. 



The root rots of sugar beets, L. Peters {Ber. Dent. Bat. GesclL. 2'/ {1906), 

 No. 6, PI). 3i.J-.329). — Attention is called to the fact that a number of fungi are 

 concerned in the diseases connnonly referred to as beet root rot, and the author 

 describes the characteristic effects produced by PythUua dcharijanum and 

 Phonia hcfw. In addition to these fungi he states that Apliaiionnjccs hrvis must 

 be considered as causing a form of rot of sugar-beet roots. Specific differences 

 in the action of these fungi are pointed out. 



Top rot of sugar cane {Queensland Agr. Jour., 16 {1906), No. S, pp. 498- 

 50.5). — A summary is given of investigations on the top rot of sugar cane, a 

 disease which has been known in Australia for a number of years. In some 

 seasons nearly the whole crop has been a failure, while in other cases the re- 

 duction in yield has amounted to over 20 to GO per cent. 



The disease can be first recognized near the center of the heart of the young 

 sprout. The leaves at this very eai'ly stage of the disease are paler than the 

 ordinary color, and the heart becomes a yellowish brown, while the expanding 

 leaves are thinner than usual, somewhat dry, and slightly curled. The ap- 

 pearance of the different parts of the cane plant as affected by this disease is 

 described, and the liability of different varieties to disease is considered. 



Th.e changes shown in the early symptoms of the disease seem to be the con- 

 sequence of chemical processes, as neither fungi nor bacteria are to be found in 

 the earliest infected parts of the plant. The chemical changes effect disorgani- 

 zation and death of the plant cells, and the wounds thus made are invaded by 

 various kinds of fungi and bacteria. Various other theories have been advanced 

 as to the cause of the disease, but the author l)elieves that it is due to chemical 

 changes. ])()ssilily indut<Ml through Mtmospbcric and soil conditions. 



Investigations on some diseases of tobacco in France, G. Delacroix {Ex- 

 tract from Ann. Inst. Nat. Agron., 2. ser., J (1006). No. 1. pp. 92, fig.'i. 17). — 

 Extended descriptions are given of a bacterial canker of tobacco due to Bacillus 

 (eruginosus, several bacterial diseases which follow insect injuries, the mosaic 

 disease of tobacco, leaf spot disease caused by Bacillus macuUcola, a root rot 

 due to Fusarimn tahacivorum, a sclerotium disease, several leaf rusts, albinism, 

 chlorosis, etc. The symptoms of the diseases are noted, the organisms, so far 

 as known, are technically described, and the results of inoculation exi)eriments 

 in establishing the causes of the diseases are stated. Brief bil)liographies are 

 given of literature relating to each disease and, where known, preventive treat- 

 ments are reconnnended. 



Tobacco wilt in South Africa, C. P. Lounsbury {Agr. Jour. Cape Good 

 Hope, 28 {1906), No. 6, pp. 784-803, figs. 9). — The author describes a disease 

 of tobacco which is attributed to the potato moth or leaf miner {Gelechia oper- 

 culella). This disease is in some respects quite similar to the wilt of tobacco, 

 as described from this country and from Japan. Notes on these two diseases 

 are appended. 



A new fungus of economic importance, R. E. Smith and Elizabeth H. 

 Smith {Bot. daz.. ',2 {1906), No. 3. pp. 215-221, figs. 3). — Among tlie investi- 

 gations that are being carried on by the California Experiment Station is that 

 on a destructive rotting of lemons which occurs in southern California and 

 within a few years has become a serious trouble to lemon growers and ship- 

 pers. The rot is usually called brown rot to distinguish it from the blue mold 



