DISEASES OF PLANTS. 449 



Since tho puhlioation of tlio proli miliary note on tliis ilisoase. opportunity lias 

 l)een offorod to compare notes and specimens of a similar disease of alfalfa, and 

 so far as tho autliors' observations j;;o tlie fun^i occnrriiii,' on clover and alfalfa 

 are identical. On l)oth clover and alfalfa considenilile injury is reported, and 

 in tli«> clover fields of T(>nuesse(> tliis disciise .-ippears to be tlie most destructive 

 fundus disease Ivuown. 



There appear to be in the case of clover 2 critical periods when the plant is 

 especially subject to tlie disease. The first is when the seedlinss encounter tlie 

 first prolonjxed hot spell duriiii,' summer, at which time the disease attaclcs the 

 petioles. Tliis appears to I)e tlie period of jjjreatest injury. The other period of 

 especial susceptibility is during; llie ripening; of tlie seed, when tlie severest 

 attacl<s are observcvl on tlie stems just at or slif^htly below the surface of the 

 i,'rouii(l. .Many flower lu-ads are destroyed by attacks just below them, the host 

 plant as a wliolc ai>|»earins usually to survive. The statements given are gen- 

 eral in cliaracfcr and more detailed descriptions will be given later. 



Thi' name ('(jJlvtotridi iini frifolii n. sp. lias been giv(>n the fungus, a tech- 

 nical description of whicli is ai>peiidcd. 



Indian wheat rusts, E. .7. Butler and J. M. Hayman {Mem. Dept. Agr. 

 India, Hot. Scr., I (IHOd), ^(). 2. pp. 1-52. pis. .5).— According to the authors' 

 investigation :t distinct species of I'ust are i)revalent in India, black rust (Piic- 

 <inia unnnhiLs). yell(»w rust (P. f/liimannii) . and oi'ange rust (P. tritiriiia). all 

 three of these species attacking wheat, while barley is subject to attacks of 

 the first 2 species. 



In different districts of India the different species found on wheat vary, P. 

 Irifidiia being the most common in eastern districts, /'. i/rainitiis in southern, 

 and /'. (/UnnariDn in the northern part. The only intermediate hosts for any of 

 these rusts known in India are the l)arl)erries near Simla, which bear the 

 a'cidia of /'. (irainini.'^. 



In India oats are not attacked by the black rust of wheat or barley, the par- 

 licular physiological race of P. t/nnniiiis which attacks oats apparently not hav- 

 ing been introduced. 



Studi.es were made of these different rusts, their distribution, relationship. 

 host plants, etc., and from the data obtained it is believed that it would be 

 jiosslble to begin investigations on the production of resistant varieties of wheat 

 on a rational plan. It is shown that in these breeding experiments the resist- 

 ance to different sjiecies will have to be considered separately, since resistance 

 to one iiarticular rust does not imply resistance to others. 



Flower infection by smuts, O. Brefelo and R. Falck {Uniersuch. Gesani. 

 Gch. Mi/h-oL. 1!)0.-,, \o. ].i: (ihs. in Hot. VriithL, 101 (1906), No. 8, pp. 212, 213).— 

 As a result of prolonged e.xperiments the authors have determined the means of 

 smut infection and dissemination in the case of a number of species. 



Infection experiments with loose smut of wheat show that the infection takes 

 place in the flowers and not when the plant is in the seedling stage. The same 

 is true for barley smut, and seed treatment for the prevention of these diseases 

 is worthless. To combat these diseases selected seed from crops that are free 

 from disease is the only practical means, and the seeds should be sown upon 

 smut-free sf)ils. 



With oats there seems to be evidence of abundant infection during the seed- 

 ling stages, and this is also the case witli the millet smuts and some other 

 species. 



Previous investigations show the infection of corn by means of aerial coiiidi:i 

 produced from smut masses in freshly manured soils (E. S. R.. 7, i). r>0.3). 



Combating the stinking smut of wheat and rye, A. Volkart {Lunilic. 



