414 OHIO EXPERIMENT STATION: BULLETIN 214 
It appears at this time that the early topping of the white onions, leaving a 
green neck, offers an inviting way for the disease to enter; that the invasion is 
‘in this direction appears from the sclerotia of the fungus which forms in this 
region. (See illustrations). The disease appears to grow worse with continu- 
ous cropping of onions and the losses have recently been so large in storage as 
to render storage of white onions unprofitable. Ithas been suggested by this de- 
partment that the white onions should be gathered and ricked in crates at once, 
either in buildings or covered with tent or temporary enclosure of building paper 
and disinfected or treated with formaldehyde gas as per the spray calendar. 
(See formula elsewhere). The enclosure shoud not be opened for 24 to 48 hours 
after treatment. In this manner it is hoped to keep down the infection of the 
white onions as well as of any others from similar troubles. 
Heart-Rot. (Bacterial). This disease has been under investigation and 
appears to come in all varieties of onions, following the topping, by its rapid 
invasion of the center of the bulb through bacterial infection. It should be con- 
trolled by attention to disinfection of the topping machine or to similar treat- 
ment to that recom- 
mended for dry-rot. 
This disease ends in 
the complete destruc- 
tion of the bulbs 
through a soft rot dif- 
erent from that de- 
scribed under soft- 
rot. 
Smudge. This fun- 
gus (Vermicularia 
circinaus Berk.) de- 
velops as asuperficial 
spotting upon the ex- 
terior, especially at- 
tacking the white 
varieties; it is really 
an anthracnose of 
onions. For some 
time, because of its 
coincident develop- 
ment with the black 
Fig. 64. Onion spotted by the smudge fungus. This fungus be- neck or dry-rot, these 
comes very bad in land where successive crops of onions are grown. two troubles have 
The fungus is also a factor in causing dry-rot of onions and set onions. been confused. It 
is now apparently 
clear that there is no connection between the two, although this fungus causes 
dry rotting of sets and bulbs. The smudge fungus is cumulatively worse 
on old land where onions are grown consecutively. Apparently also in addition 
to rotation of crops the formalin drip treatment described under smut gives 
good results in keeping down this fungus. In field experiments made _ hereto- 
fore, the onions have been lost in storage from the dry-rot and the smudge 
disease has not been studied very fully in storage; apart from this it is believed 
to have little or no connection with the commoner storage rots, although the dis- 
figuring effects of badly spotted onions reduce their market value, and rotting 
does take place as a result of it. The illustrations give characteristic appear- 
ances of these compared with healthy onions. 
