Feb. 15, 1925 
Control of Mycelial Neck Rot of Onion 
369 
which in the previous year had pro¬ 
duced onions for the first time. The 
sets were harvested on August 16 and 
placed in the standard shallow crates 
and the latter were stacked in the field 
to cure in the usual manner. During 
the next two weeks clear bright weather 
prevailed with no rain, so that condi¬ 
tions for natural curing were as good as 
ever occurs under Wisconsin conditions. 
On August 30, 12 crates of these onions 
were removed to the warehouse and they 
were divided into two lots of 6 crates 
each. No sign of neck rot was noted 
at this time, although later observa¬ 
tions indicate that infection had already 
occurred. Five crates of one lot were 
placed in the drier on September 3, 
and one crate was reserved as control. 
A second lot of White Portugal onion 
sets was secured from an adjoining 
field where onions had been grown for 
the first time. These were harvested 
on August 30 and were removed to the 
warehouse at once without the usual 
field curing. There was no evidence of 
neck rot at this time. One crate was 
given no further treatment, but was so 
placed as to afford free air circulation 
and protection from rain. One crate 
was placed in the drier on September 3, 
and kept there for seven days. The 
remaining two crates were kept damp 
for one week. One of these was given 
no further treatment; the other was 
placed in the drier for seven days. 
After treatment, the onions were 
stored in a standard onion warehouse 
Table IV.— The effect of artificial drying upon the development of mycelial neck 
rot in White Portugal onion sets, 1917 
| Condition at end 
Lot 
No. 
History previous to ex¬ 
periment 
Crate 
No. 
Num¬ 
ber of 
days in 
drier 
Hours 
'of storage period 
] 
Nature of treatment 
above 
90° F. 
i Bulbs 
Shrink¬ 
showing 
age in 
i 
neck rot 
weight 
Per cent 
Per cent 
I 
Grown on soil which had 
1 
0 
(0 
; 9 
18 
produced onions pre- , 
2 
2 
28 
3 
11 
vious year for first 
All but crate No. 1 placed in 
3 
4 
47 
1 2 
11 
time. Harvested Aug. ; 
drier Sept. 3. 
4 
6 
58 
3 
11 
16; cured in standard 
5 
8 
88 
1 
10 
crates in field for two 
6 
16 
164 
0.5 
11 
weeks of dry, clear, j 
7 
0 
0) 
, 50 
55 
and thus very fa- ; 
All artificially dampened and 
8 
0 
( 2 ) 
: 27 
45 
vorable weather. Re- j 
kept damp for one week; 
9 
2 
21 
7 
19 
moved to warehouse 
then all but crates 7 and 8 
10 
6 
57 , 
9 
17 
Aug. 30. ! 
. placed in drier Sept. 10. 
11 
9 
92 
9 
29 
| 
12 
14 
117 
10 
17 
II 
Grown on soil new to | 
onions. Harvested 
Aug. 30 and removed 
to warehouse at once. 
(No further treatment_ 
13 
0 
0) ! 
73 1 
44 
49 
In drier on Sept. 3.. 
14 
7 
7 
19 
E'pnt damn f In drie r 10 - 
l^SjN^tbertreat- 
15 
} 16 
1 
7 
0 
65 
10 
92 
26 
97 
1 Untreated. 
One crate was then removed from the 
drier to the warehouse at two-day 
intervals. In this and subsequent 
trials the outer scales of the bulbs 
appeared to be thoroughly dry after 
exposure of two days, but the treat¬ 
ment was extended much longer in 
order to determine any possible benefit 
of longer exposure. 
In order to increase possibilities of 
infection and to simulate extreme 
weather conditions, the remaining six 
crates of sets were dampened and kept 
damp for one week. One crate was 
then set aside without further treat¬ 
ment. Another was dried in the sun 
for several days according to the usual 
commercial method. The remaining 
four crates were placed in the drier and 
one crate removed after 2, 6, 9, and 14 
days, respectively. 
2 Dried in sun. 
at Racine. On January 4 following, 
final notes were taken. The percent¬ 
age of neck rot was estimated by 
examining several hundred sets in each 
crate. Each crate was then given the 
usual commercial sorting in which all 
excess chaff and decayed bulbs were 
removed. The weight of marketable 
sets was then determined and the 
shrinkage by weight for each crate was 
calculated. The results are summarized 
in Table IV. 
In spite of the good weather condi¬ 
tions which prevailed, 9 per cent of the 
bulbs in Lot I and 44 per cent of the 
bulbs in Lot II decayed in the un¬ 
treated crates. Where either lot was 
exposed to damp conditions for a short 
period the amount of infection was in 
each case greatly increased. In all 
cases the artificial drying showed bene- 
