Southeastern U.S. Vegetable Crop Handbook - 2021 - 239

DISEASE CONTROL
TABLE 3-22. DISEASE CONTROL PRODUCTS FOR ONION (cont'd)
E. Pfeufer, Plant Pathologist, University of Kentucky; B. Dutta, Plant Pathologist, University of Georgia
Minimum Days
Disease
ONION (dry)
Damping off
(Pythium spp.)
Material
mefenoxam
(Ridomil Gold)
metalaxyl (various)
azoxystrobin + mefenoxam
(Uniform)
Downy mildew
(Peronospora destructor)
acibenzolar-S-methyl
(Actigard)
ametoctradin + dimethomorph
(Zampro)
chlorothalonil + cymoxanil
(Ariston)
cyazofamid
(Ranman)
famoxadone + cymoxanil
(Tanos)
fenamidone
(Reason)
fluazinam (various)
fluxapyroxad + pyraclostrobin
(Merivon)
mandipropamid
(Revus 2.08 F)
mefenoxam + chlorothalonil
(Ridomil Gold/Bravo)
oxithiapripolin +
mandipropamid
(Orondis Ultra)
FRAC
Code
4
4
21
45+40
M+27
21
11+27
11
29
7+11
40
4+M
49
+40
Rate of Material
Formulation
Harv. Reentry Method, Schedule, and Remarks
0.5 to 1 pt/trt acre -
2 to 4 pt/trt acre
0.75 to 1 oz/acre
14.0 fl oz/acre
1.6 to 2.4 pt/acre
2.75 to 3.0 oz/acre
8.0 oz/acre
5.5 fl oz/acre
1.0 pt/acre
8 to 11 fl oz/acre
8 fl oz/acre
2.5 lb/acre
5.5 to 8.0 fl oz/acre
-
11 + 4 0.34 fl oz /1000 ft -
7
7
3
7
7
7
7
14
7
2
2
0.5
See label for row rates. Also for green onion.
Preplant incorporated or soil surface spray.
In furrow treatment.
Suppression only. Also labeled for Iris yellow spot virus and
bacterial leaf blight.
12 hr Begin applications prior to disease development and continue
on a 5 to 7 day spray interval.
0.5
0.5
0.5
0.5
1
0.5
0.5
2
4hr
Apply prior to favorable infection periods; continue on 7 to 9
day interval; alternate with a different mode of action.
Use a surfactant for best results.
Apply preventively on a 5 to 7 day schedule and do not
rotate with group 11 fungicides.
Use as soon as environmental conditions become favorable.
Initiate sprays when conditions are favorable for disease or
at disease onset. Spray on a 7 to 10 day schedule.
Suppression only. Apply at disease onset; continue on 7 to
14 day schedule. No more than 3 applications/season
Apply prior to disease development and continue throughout
season at 7 to10 day intervals; maximum 24 fl oz per
season.
Use with a suitable adjuvant.
Use higher rate if disease is present. For best results, begin
the disease resistance program with an initial treatment at
planting or trans- planting with a fungicide registered for its
use. Apply Orondis Ultra as a foliar spray in a mixture with
copper-based fungicide beginning at first appearance of
symptoms.
pyraclostrobin + boscalid
(Pristine)
Leaf blight
(Botrytis spp.)
azoxystrobin (various)
azoxystrobin + chlorothalonil
(Quadris Opti)
penthiopyrad
(Fontelis)
cyprodinil + fludioxonil
(Switch)
dicloran
(Botran)
difenoconazole + cyprodinil
(Inspire Super)
fixed copper (various)
pyraclostrobin
(Cabrio)
pyrimethanil
(Scala)
11+7
11
11+M
7
9+12
14
3+9
M
11
9
18.5 oz/acre
6.2 to 15.4 fl oz/acre
1.6 to 3.2 pt/acre
16 to 24 fl oz/acre
11 to 14 oz/acre
1.5 to 2.7 lb/acre
16 to 20 fl oz/acre
See labels
12 oz/acre
9 or 18 fl oz/acre
7
7
0.5
0.5
7
7
14
3
7
14
7
1
4 hr
0.5
For suppression only. Make a maximum of 6 applications
per season.
Make no more than two sequential applications before alternating
with fungicides with a different mode of action. Apply
no more than 2.88 qt per crop per acre per season.
Make no more than one application before alternating with a
fungicide with a different mode of action.
12 hr Begin sprays prior to disease development and continue on
a 7 to 14 day schedule.
0.5
0.5
0.5
Do not plant rotational crops other than onions or strawberries
for 12 months following the last application.
Use lower rate in a tank mix with broad-spectrum fungicide
and higher rate when applied alone. Do not apply more than
54 fl oz per crop.
Make no more than two applications before alternating with
a fungicide with a different mode of action.
Spray at first appearance, 7 to 10 day intervals. Do not
apply to exposed bulbs.
Make no more than 2 sequential applications and no more
than 6 applications per season.
Use lower rate in a tank mix with broad-spectrum fungicide
and higher rate when applied alone. Do not apply more than
54 fl oz per crop.
2021 Vegetable Crop Handbook for Southeastern United States
239
Southeastern U.S. Vegetable Crop Handbook - 2021

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