50 
Tolokado Experiment Station 
RYE 
Flag Smut (Urocystis occulta) (52) — This is the only smut affect- 
ing rye. Masses are formed on the leaves and stems as well as the 
kernels. Affected plants are usually stunted and seldom produce 
normal heads. On the leaves long gray blisters are first formed Avhich 
on breaking open expose a mass of black spores. Similar blisters 
are found on the stems often causing them to become twisted and 
curved. If heads are produced they are nearly always empty or 
else the kernels have been replaced by masses of smut spores. 
The spores may live over either on the surface of healthy rye 
kernels or in the soil. The formaldehyde seed treatment together 
with crop rotation is effective in controlling rye smut. 
SORGHUM 
Under the name sorghum are 
included niilo, kaffir, feterita, dur- 
ra, broom corn, sudan grass and 
shall u. 
Kehiel Smut (Sphacelotheca 
sorghi) — This is the most common 
smut of sorghum. As the name in- 
dicates the kernels alone are af- 
fected, each kernel becoming a 
mass of smut spores. The head 
retains its usual shape and form. 
The spores live over on the surface 
of normal seed and infect the plant 
as soon as the seed germinates. The 
formaldehyde treatment is ef- 
fective. Milo is resistant to all 
smuts. 
Head Smut (Sorosporium reili- 
anum) — Head smut is not common 
in OoloT'ado. The entire heads of 
infected plants become a large do- 
forrned mass of smut spores. Head 
smut differs from kernel smut in 
that the s])ores are not necessarily 
carried with the seed but is wind 
distT*ibuted affecting the ])lant 
either from the soil or above ground. Seed treatment therefore 
is not effective. Milo is I’csistant to head smut as well as to kernel 
smut. 
Kernel smut of sorghum. 
