38 Agricultural Kxperhneiit Station Research Bulletin 
THE INFLUENCE OF OTHER ORGANISMS 
It is very j^ossible that a larger number of infections and a 
more extensive develo2:>ment of the fungus Avithin the host occur 
in the field than under the conditions of controlled inoculations 
because of the j^resence in the former of associated parasitic 
organisms and the injuries caused by them, or because of other 
injuries of the roots caused b}" insects, mechanical tools, or im- 
proper culture. This may oftentimes be of especial importance 
in connection with Fnsavium spp., which are not as strict para- 
sites as some and therefore enter more readily thru wounds. Two 
such organisms of the soil, namely, Rhizoctonia and Sclevotium 
Tolfsii^ were noticed affecting soy beans in fields where the 
Fusariwn blight was abundant. The soy bean is more resistant 
to Rhizoctonia than most garden and field crops but lesions were 
noted on seedlings, young plants, and the small roots of older 
plants. Sclevotium rolfsii^ however, is very destructive to soy 
beans whenever present and kills plants at all stages of their 
growth. 
Soy beans are now growing in soil inoculated with Fusarium 
traclieiphilum and Rhizoctonia^ and in another soil inoculated 
with Fusarium tracheiphilum aSid Sclerotium rolfsii. and it is be- 
lieved by the Avriter that either these or other organisms Avill be 
found to pla}^ an important part in the development of this dis- 
ease. It seems probable from preliminary tests that Fusarium 
tracheiphilmn is unable to penetrate soy bean roots to the xylem 
elements unaided but that, once it gains entrance thereto, it 
develops raj)idly in them in a somewhat saju-ophytic manner, 
obscures the j^rimary injury, and linally affects the host as 
previously described. 
FIELD EXPERIMENTS TO DETERMINE THE SUSCEPTIBILITY OF ] 
VARIETIES 
Sixty ])er cent of the Mammoth Yellow soy beans in the lield I 
at Eed Springs, N. C., Avere blighted in 1915. The main part | 
of this tield Avas ])lanted to the same variety on May ‘J3, 19l():| 
but in another ]>art resiu’ved for the ])ur|)ose, one 54-met(‘r row 
each of I laluM-landt, Mammoth Yellow, IVkin, Ulack Eyebrow, 
Medium b ellow Abrjinia, and Tar Heel Black soy beans and a 
roAv of Clay coAvpiais AV(M*e ])lanted on flune 8. On August 10 
the main li(‘ld and all of tlu‘ varieties in the test, including the 
cow|)(‘as, shoAved considerabh' blight or Avilt, except the Black 
Eyebrow and the Abrginia vari(‘ti(*s of soy beans. On -Vugust 20 
the latter of these varieties Avas apparently free from disease, but 
*the jdants had declined Avith age to sudi an extent that the exact ' 
