650 
Journal of Agricultural Research 
Vol.XXl, No. 9 
dead for several feet or even several yards. The disease may follow a 
row or extend across two or more rows, which are about 8 inches apart. 
The dead plants have a dark, moldy appearance, which indicates slow 
death and the presence of various saprophytic fungi. Alternaria and 
Helminthosporium are commonly present on these dead plants. Plants 
which are killed by maggots are usually lighter in color, due to the rapid 
drying after the stems are severed from the roots. The base of the stem 
and the roots of diseased plants are dark in color and often have a frosty 
appearance, due to the presence of wefts of the mycelium of the causal 
fungus. Brown sclerotia may be found attached to the roots or the base 
of the stem of diseased plants. Plants attacked by this fungus are not 
so easily removed by pulling as are plants severed at the base by root 
maggots, although the roots are almost completely decayed by the time 
the plants are dead. Infected plants first show a stunted condition 
accompanied by yellowing and withering of leaves, and a high percentage 
of the plants may show a distinct lack of chlorophyll or “ pseudo-albino r ’ 
condition, which may appear as white stripes in the leaves or as almost 
totally white leaves. Part or all of the leaves on a plant may show this 
condition. Rice seedlings weakened by other root troubles in some cases 
may show this same lack of chlorophyll. Plants badly affected die 
slowly, the tips and margins of leaves dying first and thus affording a 
medium of early attack by saprophytic forms. Plants that survive until 
the irrigation water is applied, if not too nearly dead, usually recover, 
due to the fact that water immediately checks the development of the 
fungus. 
importance: or tiir dise:asr 
The distribution of the disease is not known, and consequently no 
estimate of damage can be given. In localities where it occurs, however, 
considerable losses may result. Early sown rice seems more subject to 
attack by the fungus than that sown later. This probably is due to the 
fact that seed sown later germinates more readily and the plants grow 
more vigorously, thus giving the fungus less chance to overcome them 
before the irrigation period. The quantity of fungus material may be 
reduced somewhat because of the decrease of organic matter in the soil 
which serves as food for it. The fact that a large percentage of the seed¬ 
lings may be destroyed before emerging from the soil makes the disease 
more important than might be suspected from the dead seedlings seen in 
the field. By digging into the soil, seedlings in various stages of devel¬ 
opment are found to have been destroyed. 
Still more importance was attached to this disease when an apparently 
identical fungus was found growing in abundance on soybean plants on 
the station farm where the soybean is being considered as a desirable 
crop to rotate with rice. If these forms proved to be identical there 
would be considerable danger of disseminating the fungus with soybean 
seed. 
