490 SUMMARY OF CURRENT RESEARCHES RELATING TO 



which affects the tubers and is caused by an organism allied to finger- 

 and-toe. Experiments have shown that if seed potatoes are treated with 

 a solution of formalin and water, or soaked for 24 hours in 2 p.c. copper 

 sulphate and washing soda, the resultant crop is quite healthy. Cases of 

 leaf-curl caused by Verticillium albo-atram, and black speck scab due to 

 a Corticium, are also recorded. Violet root-rot fungus, Rhizoctonia 

 violacea, was observed for the first time in Ireland on potatoes from 

 Co. Mayo. 



C. E. C. Fischer * has studied the disease of timber trees due to 

 Festal ozzia Hartigii. It attacks the seedlings, killing the cambium all 

 round the stem, its presence being easily recognized by a constriction at 

 the spot. Fischer grew the spores of the fungus in water, prune-juice, 

 and in a jelly of meat and malt extract ; the spores were reproduced 

 in from 14 to 40 days. No other form of reproductive organs were 

 obtained during eight months' culture, and all attempts at artificial 

 infection of living plants failed. 



Flora W. Patterson t describes a new species, Stemphylium Tritici, 

 which is often associated with sterile florets of wheat. Artificial inocula- 

 tion resulted in 9 p.c. of sterile florets. In nature it is prevalent on the 

 leaves and is almost invariably present in diseased ovaries. 



Griffon and Manblanc J have studied the heart-rot of beet-root, 

 due to the fungus Phoma tabifica. They distinguish this malady from 

 the rotting of the leaves caused by a Gladosporium ; in pure cultures of 

 Phoma the same pyenidial stage was always reproduced ; the form of the 

 mycelium was, however, somewhat modified in artificial cultures. 



In a recently issued leaflet from the Board of Agriculture § on straw- 

 berry cultivation, attention is called to two leaf diseases of the plants, 

 Sphserella Fragarise — which begins by forming dark brown spots, and 

 finally killing the leaf — and Spliserotheea Gastagnei, a mildew which appears 

 first on the under surface of the leaves and spreads to the fruit, which it 

 utterly destroys. The same fungus causes mildew of hops. Spraying 

 with Bordeaux mixture is recommended in each case. 



Em. Marchal || reports the appearance in Belgium of the American 

 gooseberry mildew. The outbreak is not due to the importation of in- 

 fected plants, but probably to the visit of a traveller from Holland, whose 

 own bushes were infected. Vigorous measures were taken to stamp out 

 the disease, and these have been effective for the time. 



Corky scab of potatoes (Spongospora scabies) has recently appeared in 

 South Africa, having been imported with tubers consigned to Rhodesia 

 and to the Transvaal for planting. J. B. Pole Evans,l the plant patho- 

 logist, detected the disease on the potatoes, and describes it so that 

 growers may be able to recognize it, and to avoid planting affected tubers. 



Pole Evans ** also describes a disease of the lemon, caused by the 

 fungus Diplodia natalensis sp. n. The fungus enters the fruit by the 



* Joum. Econ. Biol., iv. 3 (1909) pp. 72-7 (1 pi.), 



t Bull. Torrey Bot. Club, xxxvii. (1910) p. 205. 



X Bull. Soc. Mycol. France, xxvi. (1910) pp. 126-31 (1 pi. and 1 fig.). 



§ Board of Agriculture and Fisheries, Leaflet No. 207 (1910) G pp. 



|| Bull. Soc. Roy. Bot. Belg., iv. (1900) pp. 337-8. 



\ Transvaal Agric. Journ., viii. (1910) pp. 462-3 (1 pi.). 



•* Tom. cit., pp. 463-5 (1 pi.). 



