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18 
Agriciiltirral Kx per uneat Station Research Bulletin IJf 
CULTURE MEDIA AND THEIR VARIOUS EFFECTS ON SPECIES OF 
FUSARIUM 
111 making a cultural study of these fungi mucii care vras 
taken to follow the suggestions of Appel and iVollenweber (i), 
Wollenweher (81, 32), and Sherhakoff (23), in order to determine 
what criteria to employ in judging normal growth characters. It 
is generally believed that standardization of cultural methods is 
highly essential in the comj)arative study of so difficult a group 
of fungi. 
The writer has kept the soy bean and the cowpea strains 
under constant obser^'ation for three years and other strains for a 
])art of this time, on Auirious kinds of ‘iiatural and artilicial 
media” and under Avidely Auiriable physical conditions. lie is 
therefore familiar Avitli the possible A^ariability of members of this 
genus. 
Since a large number of the media used did not jArove to be 
of special diagnostic value, they are not discussed here. Among 
the media most commonly employed and serving some particular 
jAurpose Avere oat, potato, and string-bean hard agars (3 per cent 
agar), Avhich, because of the paucity of moisture (23, p. 100), 
giA'e all forms of fructification Avith ‘biormar' spores. FiA^e to 10 
])er cent of dextrose Avas added to agars to favor the production 
of ])igment. The addition of this sugar, hoAveATr, favored the 
develo])inent of mycelium at the exjxuise of macroconidia, and 
Avhen from 8 to 10 per cent Avas added these sjAores Avere often 
absent. GroAvth on steamed rice in test tubes from Aveighed 
quantities of rice and measured amounts of Avater to obtain uni- 
formity also results in the formation of j)igment and sometimes 
an odor that is tAq^ical for certain related s])ecies of Fusarlum. 
Herbaceous and Avoody stems, string-bean pods, and potato plugs 
give the best develo])ineut of si)orodochia and pionnotes.^ Potato 
])lugs also seiwe for the proper deATdopment of sclerotia and 
colors, both of Avhicli may be reduced or absent from stem plugs 
AvluMi tluMV is a minimum deA'elopmeut of mycelium. 
According to A'olleuAveluM- (3)1. p. 37), vii*ul(‘uc(‘ is commonly 
maiulaiu(‘d on sI(mu plugs. LiA’ing sti'rile soy bean and coAvpea 
s(*c(llings grown in ()-inch ti‘st lubes were also used and ai*e 
(houglit lo b(‘ a b(‘ll(‘r nuMlium for maintaining virulence in the 
strains from tlu‘ rc'spcct i\(‘ hosts. 
In order to obtain sterile seedlings for this purpose the seeds 
AV(M’(‘ first washt‘d for o mimiti'S in t(‘pid Avatiu* and avimv then 
j)lac(‘d in concent ratial sulphuric acid foi* 20 minutes. Formalin, 
nuM-curic chlorid, both in acnu'oiis and alcoholic solution, and 
U*'or a discussion of these terms, see Wollenweher (31, p. 24). 
