DISEASES OP PLANTS. 49 



was reduced to as low as 42°. By this treatment the smut spores were de- 

 stroyed and relatively little injury was done the seed grain except where the 

 temperature was above 64°. It is believed that this method of treating grain 

 has advantages, and that if the temperatui-e is allowed to go above 60° the dura- 

 tion of treatment should be reduced. 



The rust of wheat, E. Vernet (Prog. Agr. ct Vit. (Ed. VEst-Ccntre), 30 

 (1009), No. ^0, pp. Jt28-433). — An account is given of a number of varieties of 

 wheat that have proved resistant to wheat rust (Puccinia graminis). 



Fungus maladies of the sugar cane, N. A. Cobb {Hawaiian Sugar Planters' 

 Sta., Div. Path, and Physiol. Bui. 6, pp. 110, pis. 7, figs. 6//).— This bulletin is in 

 continuation of a previous one of the same title (E. S. R., 18, p. 843) and gives 

 supplementary observations upon a number of the diseases previously described, 

 together with notes on some diseases not treated in the former publication. 



Particular attention is given to the root diseases of sugar cane. The author 

 states that there are 5 fungi connected with the root diseases, Marasmius sac- 

 chari, M. hatvaiiensis, Ithyphallus coraJloidcs, Clathrus trilobatus, and a fungus 

 as yet undetermined but which is characterized by the occurrence of stellate 

 crystals upon the mycelium. In addition it was thought probable that Dictyo- 

 pliora sp. may cause a root disease of cane. 



Additional notes are given on the witlier tip of the cane leaf, a disease appar- 

 ently of fungus origin, which, while not serious, may delay the grovv'th of the 

 cane to some extent. The relation between the pineapple disease of cane, due 

 to Thielaviopsis cthaceticus, and a disease of pineapples is pointed out, and 

 notes are given on the ring-spot disease of the cane leaf (Leptosphwria sac- 

 chari) and the eye-spot disease (Cercospora sacchari). A possible relation 

 between the rind disease and seed cane is pointed out in that the top shoots 

 containing buds and but little sugar are often discarded or used for planting. 

 These stalks apparently are capable of carrying over the rind disease from one 

 crop to another. 



Remedies for the diseases are discussed, after which an account is given of 

 nematodes. Since the previous publication the author states that two addi- 

 tional species have been found parasitic on the roots of cane, one of the species, 

 Tylenchus biformls, being described as new. 



The bulletin concludes with a discussion of timber rots due to fungi, and 

 suggestions are given for their control. 



The root rot of tobacco caused by Thielavia basicola, W. W. Gilbert ( U. S. 

 Dept. Agr., Bur. Plant Indus. Bui. 158, pp. 55, pis. 5). — According to the author, 

 a root disease of tobacco due to T. basicola has caused considerable loss to 

 growers in different sections of the United States. 



The fungus attacks the roots, blackening them and causing their decay. If 

 attacked while very young the seedlings are killed, in much the same manner 

 as by the damping-off fungi. In other cases, where the conditions do not favor 

 as severe an attack, the roots are invaded and the plants stunted. The stunted 

 condition of the plant may be often observed in the field where diseased material 

 has been transplanted. When badly diseased plants are set in the field they 

 may turn yellow, wilt, and die to such an extent that often large areas must 

 be replanted. 



A description is given of the fungus and historical data are presented on its 

 discovery and distribution, its host plants, etc. 



Experiments were carried on to test the practicability of treating seed beds, 

 and it was found that steam sterilization gave best results, followed by surface- 

 fire treatment. Two plats treated with formalin are said to have been but 

 little better than an untreated check plat, but several reasons are advanced to 

 account for the failure. 



