DISEASES OF PLANTS. 467 



fiiiigiis in which its parasitism was definitely estabHshed, Imt all attempts to prochiee 

 the niifro- and maeroconidial phases of the fun«;ns, in sterilized media, failed. Later 

 specimens of diseased eanes were fountl vvhicli, being split o])en, showed an abmidant 

 development of sjKires which, from their size and origin, agreed with the micro- 

 and jnacroconidia describeil by Massee. Cultures n^ade with these spores readily 

 developed the Melanconium phase of the fungus. Spores of this kind are seldom 

 met with in Barbados, the Melanconium stage being the predominant form. So far, 

 all attempts to inoculate a healthy cane with the spores, without wounding the plant, 

 failed. However, the tunnels of the moth borer provide means of entry for the 

 spores, and infection speedily takes place. It is said that little attempt is made in 

 Barbados to keep the fungus under control. Large piles of rotten cane are left in 

 the fields to serve as centers from which the disease may be widely syjread. Inocu- 

 lation experiments were made in the field with the micro- and macrocouidia, in 

 wliich precautions were taken to prevent the entry of other spores, with the result 

 that the tissues of the canes became infested in 8 to 10 days, while control specimens 

 showed no infection. An .xtended search of diseased canes has so far failed to reveal 

 the presence of any perithecia, and as a result the ascigerous stage of the fungus in 

 tliis region is as yet unknown. 



Fungus diseases of sugar cane, A. Howard (WeM Indian BiiL, 2 {1901), No. 

 1, pp. 46-56). — An account is given of the rind and root rot of sugarcane. The 

 effect of the diseases is described, and it is stated that there is i)rol )ably a very close 

 connection between the fungi causing them. Whether they are identii-al remains to 

 be determined. Various suggestions are offered for their control, among them that 

 all rotten canes be burned, and that a rotation of crops and a selection of healthy 

 plants and disease-resisting varieties be practiced. 



Powdery milde-w of the apple, L. H. Pammel [Contrih. Depf. Bot. Iowa State 

 Col.Atjr. andMeeh.Artti, 1900, No. 17, pp. 177-182, pis. 3). — A review is given of some 

 of the literature and synonymy of the powdery mildew of the apple. The species 

 most prevalent and probably the only one in Iowa is said to he SpJwrr-othera mali. 

 The fungus is characterized, and spraying trees with Bordeaux mixture or amnio- 

 niacal copper car])onate is recommended as a treatment. 



On abacterial disease of the turnip, M. C. Potter {Proc. Rni/. Sor. lIoni}()ii'\, 

 67 {1901), No. 440, pp. 442-469, figs. 6). — In a previous publication (E. S. R., 11, p. 

 1061 ) the author called attention to the occurrence of the bacterial disease of the 

 turnip. In the present paper it is more fully described, the organism causing the 

 disease is characterized, and its methods of attack are stated. In the autumn, when 

 the activity of the turnip i)lant is devoted mainly to the storage of reserve material, 

 it is said to be very common to tind among plants still growing in the fields some 

 whose njots are quite rotten and with a highly offensive and peculiar sniell. The 

 jilants thus affected can be ret-ognized by the drooping yellowish leaves, the older 

 leaves being the first to show any indications of disease. The leaves next in age 

 exhil)it the signs of premature decay, and this proceeds until finally the young leaves 

 are attacked. The time taken for the collapse of the leaves varies with different 

 individuals, but it is about 2 weeks from the time of the first infection. 



The roots of the plants examine<l present a very characteristic appearance. The 

 decaying portion may be of grayish white or a dark brown color, and quite soft to 

 the touch. In the particular disease under investigation the infected portion always 

 remains white and on this account the (lisease is characterized as " white rot." It 

 can be readily communicated to sound roots, it being sufficient to make a slight 

 incision and add a small portion of the rotten mass upon the injured surface to imme- 

 diately set up a decay. Within 24 hours the previously healthy cells around the 

 inoculated surface will show the characteristic changes of form and color to the depth 

 of 1 in. (II' more. 



The autlmr ((Uidncted a series of cultures in whicli he finally succeeded in isolat- 



