310 SUxMiMAKY OF CURRENT RESEARCHES RELATING TO 



rounding cells are killed and a brown area is formed. The writers 

 recommend spraying by Bordeaux mixture towards the end of July and 

 careful fumigation of the store rooms. A. L. S. 



Observations on Wheat Scab in Pennsylvania and its Patho- 

 logical Histology.— J. F. Adams {Pfujtoimthology, 1921, 11, 115-24, 

 2 pis., 1 tig.). The disease known as wheat scab is due to the fungus 

 Gihberella sauMnetii, and " everything which tends to weaken the plant 

 or retard its ripening renders it more subject to attack." The writer 

 discusses the opinions of previous workers as to the causal organism and 

 its development. Generally the head of wheat is affected, though under 

 favourable conditions the fungus may become a virulent parasite of 

 seedlings. It has been noted that scab is more prevalent in fields that 

 have been previously planted by corn, probaljly from the fungus growing 

 on dead corn stalks. The prevalent type of infection occurs after the 

 flowering staije, and the developing embryo is completely destroyed. 



A. L. S. 



Resistance to Citrus Canker. — Forman T. McLean and H. 

 Atherton Lee {Phytopathology, 11)21, 11, 109-14«, 1 fig.). The 

 authors comment on the resistance to this, the bacteria canker, a disease 

 which affects the foliage and stalks of the Citrus trees, causing pustules 

 and blisters. The research has proved that on the horticultural varieties 

 of Citrus nobilis var. deliciosa (mandarin orange) the infections are 

 largely wound infections. They conclude that penetration cannot take 

 place through the epidermis of that plant, and by graft hybrids (peri- 

 clinal chimeras) with other species of Citrus resistant characters might 

 be transferred. A. L. S. 



Experimental Data on Losses due to Canker of Rose. — L. M. 



Massey {Pttytopatholoyy, 1921, 11, 125-34). The disease is due to the 

 fungus Cylindrodadium scoparium which causes cankers at the crown of 

 the plants. Infection takes place from the soil, and losses are due to 

 diminished yield of blossoms and not to the death of the host. A 

 decrease of about ten blossoms per plant (amounting to one dollar) 

 represents the annual loss to the grower. , A. L. S. 



Lotus Leaf-spot caused by Alternaria nelumbii sp. n.— Ella 

 M. A. Enlows and Frederick V. Eand (Phytopathology, 1921, 11, 

 135-40, 1 pi., 1 fig.). The disease appeared in summer 1913 at Kenil- 

 worth D.C. and in the autumn of the same year at the New York 

 Botanical Gardens on leaves of Egyptian lotus {Nelumhium speciosum)^ 

 causing spots which in time may coalesce, the leaf gradually drying and 

 curling from the margin inward. ilorphologically the fungus was 

 similar to Alternaria brassicee-nigrescens, l)ut no cross infections could 

 be obtained between that species and the lotus plant. No further stage 

 of growth was developed, but the conidia were viable after two years in 

 the laboratory, and the fungus can thus be carried on from season to 

 season by conidia alone. A. L. S. 



Notes on Species of Colletotrichum and Phoma in Uganda. — 

 W. Small (Kew Bulletin, 1921, 57-67). Colletotrichum coffeanum is 



