412 OHIO EXPERIMENT STATION: BULLETIN 214 
The amount of loss resulting from it is liable to be variable since it acts by 
general reduction of vigor and reduced filling of the grain head. Treatment 
with formalin as for smut will certainly kill the adhering spores on seed oats, 
(See bulletin 203). 
Blade Blight. A disease similar to that earlier described as bacterial dis- 
ease of oats (see Journal of Mycology, VI; 72) has been very serious in Ohio 
during the seasons of 1907 and 1908. The phenomena are those of yellowing and 
dying of older leaves associated in most cases with the presence of an abundance 
of leaf sucking insects such as aphids, mites and leaf hoppers. Recent culture 
and colonizing studies made at the Station show the disease to be due to two 
specific bacteria working together. (Bacillus avenge Manns.) (Pseudomonas 
avenge Manns), These have’been isolated and described. These bacteria are 
carried or transmitted by the insects or are scattered by natural agencies. 
In control work in cages the organisms caused infection through the punctures of 
the aphids (green flies). Evidently the control of this disease will involve 
thorough seed treatment together with possible field checking of the insects dis- 
tributed. (See bulletin 210). 
Rust. In addition to the two species of rust found upon wheat and to be 
given under that grain, there is a rust common upon oats (Puccinia coronata 
Corda.), usually prevalerit during the rainy harvest weather and more or less at 
alltimes. No remedy is as yet at hand. = 
The Scab Fungus of the oats (Fusarium i 
roseum Lk.) is the same species as for wheat 
and attacks the panicles near filling time 
It results in empty hulls with the pink fun- 
gus.- The disease also survives apparently 
as an internal infection of oat kernels and is 
capable of destroying young seedlings after 
the manner described for wheat. (See dis- 
eases transmitted in the seed and also 
wheat). Like that disease in wheat, it must - 
be controlled, if at all, by a combination of 
seed treatment for adhering spores and thor- 
ough seed recleaning to exclude all light 
kernels. ‘ %, 
Smut. The smut of oats takes on two 
forms, the loose smut ( Ustzlago Avenae Jens.) 
and the hidden smut ( Ustilago Avenae laevis 
(Jens.) Kell. & Swing). The first, which is 
the more common, converts the entire head, 
including glumes, into a sooty mass of smut 
spores (Fig. 62); while in the hidden smut the 
enclosing glumes remain about the smutted 
grain. No other essential difference has 
been found between them. Both are caused || 
by spores from smutted seed, or seed from 
smutted grain, and both are successfully 
prevented by seed treatment with hot water 
or formalin as per scheme given elsew here. | 
(See calendar and also Bulletins 64 and 97). lk. 
An increase of yield beyond smut prevention Fig. 62, Head or panicle of oats destroyed 
has usually followed seed treatment. This __ by loose smut. All the oats kernels and 
alone pays for the cost of treatment and the eatin ta ings Hace he eure 
saving from smut loss is clear profit. masses by the loose smut fungus Us#ilago. 
