122 Pflanzen krankheiten. 



headina: „Bark diseases" it is stated that no evidence of Phytoph 

 thora Faberi was obtained, and the record of this species for Ma- 

 laya by Rutgers appears to be based on insufficient evidence. 



E. M. Wakefield (Kew). 



Bijl, P. van der, „Wilt" or „Crown-Rot" Disease ofCar" 

 nations caused by Fusarium sp. (Ann. Appl. Biol. II. N** 4. p- 

 267—290. 4 pl. 1916.) 



Carnations affected by this disease show a wet rot of the stem 

 just below the soil. The lower leaves turn a sickly colour, and are 

 usually more erect. The whole plant soon dies. The causal orga- 

 nism was shown by isolation and by infection experiments to be a 

 species of Fusarium, but the question as to whether it is the same 

 as that described by Sturgis (Ann. Rep. Conn. Agric. Exp. Sta., 

 part III, 1897, p. 175-181) was not decided. 



Details of the growth of the fungus on various culture media 

 are given. 



In field experiments on the effect of soil fungicides, it was 

 found that formalin was of no use. Plots treated with quicklime 

 fared a little better than controls, but further experiments are 

 necessary. 



The disease causes considerable loss to carnationgrowers in 

 South Africa. The author advises them to use only their own 

 cuttings, taken from healthy plants; to lay the cuttings in healthy 

 ground; and to exercise a process of crop rotation for a few years 

 where the soil has become diseased. All diseased plants should be 

 destroyed. E. M. Wakefield (Kew). 



Hörne, A. S. and H. M. Lefroy. Effects produced by suc- 

 king Insects and Red Spider upon Potato foliage. 

 (Ann. Appl. Biol. I. Nos 3 and 4. p. 370-371. 5 Plates. Jan. 1915.) 



The authors experimented with seedling plants of the variety 

 of Potato known as President, both in the open and under bell- 

 jars. The principal results are as foUows: 



1. Red Spider [Tetranychus telarius). Leaves become mottled, 

 plant turns brown and dies. Epidermal and subepidermal cells 

 injured. 



2. Aleurodes vaporariorum. Effect gradual, plants weakened but 

 did not die. Conducting tissue tapped, not followed by vein dis- 

 coloration. 



3. Aphis {Rhopalosiphlum solani). Leaves with discoloured 

 veins brown and dead leaf ends, yellowing and death of the plant. 

 Conducting tissue tapped, followed by vein discoloration after nine 

 or ten days. 



4. Jassid [Eupheryx atropunctata , Chlorida viridula). White spots 

 plants did not die. Epidermis punctured, assimilatory tissue de- 

 stro3^ed. 



5. Capsid [Calocoris bipunctatus. Lygits pabulinns.) Dark brown 

 blotches on leaves and young growth, veins darken, young leaves 

 and shoots killed rapidly. Tissue lacerated causing severance of 

 the veins and leaving ragged irregulär pits which become rapidly 

 discoloured as do the veins also within two days. 



E. M. Wakefield. 



