Vegetable Seed Pathology Washington State University
Vegetable Seed Pathology Washington State University
Vegetable Seed Pathology Washington State University
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Efficacy of Fungicide<br />
<strong>Seed</strong> Treatments for<br />
Management of<br />
<strong>Seed</strong>ling Blights of Onion<br />
2008 PNVA Annual Convention & Trade Show,<br />
Kennewick, WA, 19-20 19 20 November 2008<br />
Lindsey du Toit<br />
<strong>Washington</strong> <strong>State</strong> <strong>University</strong>
<strong>Seed</strong>ling blights of onion
Pythium damping-off
Rhizoctonia seedling<br />
blight
Rhizoctonia seedling blight
<strong>Seed</strong>ling blights of onion<br />
• Pythium spp., Rhizoctonia spp., Fusarium spp.<br />
• Promoted by:<br />
• soil drainage –<br />
wet, poorly drained, low spots,<br />
compaction<br />
• crop rotations, including cover crops<br />
• decomposing organic matter<br />
• Most are NOT seedborne<br />
• Spread:<br />
• with movement of soil<br />
• irrigation water, splashing water, runoff<br />
• transplants
<strong>Seed</strong>ling blights of onion<br />
• Management:<br />
• practices that improve soil drainage<br />
• break compaction, drain tiles, raised beds<br />
• crop rotation – limited?<br />
• incorporate plant residues >8” deep<br />
• Fungicide seed treatments/drenches:<br />
• soilborne inoculum<br />
• limited duration of efficacy<br />
• spectrum – Pythium vs. Rhizoc. vs. Fusarium<br />
• Fumigants:<br />
• metam sodium, chloropicrin, …<br />
• Resistance?
2008 Onion <strong>Seed</strong> Treatment Trial<br />
Assess efficacy of fungicide seed treatments<br />
for management of several seedborne and soilborne<br />
pathogens of onion<br />
1.<br />
<strong>Seed</strong>borne fungi:<br />
Botrytis aclada, B. allii, Aspergillu spp.<br />
Kritzman’s agar assay<br />
2. Soilborne pathogens:<br />
- Rhizoctonia solani AG4 HGII<br />
- Pythium ultimum<br />
Growout assays in greenhouse
Application of a pesticide to a crop or site that is not<br />
on the label is a violation of pesticide law and may<br />
subject the applicator to civil penalties up to $7,500.<br />
In addition, such an application may also result in<br />
illegal residues that could subject the crop to seizure<br />
or embargo action by WSDA and/or the U.S. Food and<br />
Drug Administration.<br />
It is your responsibility to check the label before using<br />
the product to ensure lawful use and obtain all<br />
necessary permits in advance.
Trade name Active ingredient Trade name Active ingredient<br />
Non-treated seed,<br />
non-inoculated<br />
medium<br />
Non-treated seed,<br />
inoculated medium<br />
Farmore<br />
Farmore D300 +<br />
cyprodinil<br />
Farmore D300 +<br />
Mertect 340F<br />
Farmore D300 +<br />
Actigard<br />
Apron + Maxim +<br />
A14635<br />
Farmore D300 +<br />
Thiram<br />
D300 Mefenoxam (Apron) +<br />
fludioxonil (Maxim) +<br />
azoxystrobin (Dynasty)<br />
Mefenoxam + fludioxonil<br />
+ azoxystrobin +<br />
cyprodinil<br />
Mefenoxam + fludioxonil<br />
+ azoxystrobin +<br />
thiabendazole<br />
Mefenoxam + fludioxonil<br />
+ azoxystrobin +<br />
acibenzolar-S-methyl<br />
Mefenoxam + fludioxonil<br />
+ experimental<br />
Mefenoxam + fludioxonil<br />
+ azoxystrobin + thiram<br />
Thiram<br />
42-S Thiram<br />
Farmore D300 +<br />
thiamethoxam<br />
Farmore D300 +<br />
Trigard OMC 75 WP<br />
Mefenoxam + fludioxonil +<br />
azoxystrobin +<br />
thiamethoxam (insecticide)<br />
Mefenoxam + fludioxonil<br />
+ azoxystrobin +<br />
cyromazine (insecticide)<br />
Coronet 200 ml Boscalid+<br />
Pyraclostrobin<br />
Coronet 400 ml Boscalid+<br />
Pyraclostrobin<br />
Agricoat<br />
Agricoat<br />
800A Proprietary organic<br />
711A Proprietary organic<br />
Rovral 4F Iprodione
Materials & Methods<br />
After seed treatment:<br />
1. AOSA blotter germination assay<br />
2. Kritzman’s agar assay<br />
3. Greenhouse growout<br />
assays
Germ assay: % <strong>Seed</strong> germinated at 10 days<br />
% seed germinated at 10 days<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
No significant<br />
differences<br />
Non-trt seed, non-inoc<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
AgriCoat 800A<br />
Apron+Maxim+A14635<br />
Coronet 200 ml<br />
Coronet 400 ml<br />
Farmore D300<br />
FD300+Actigard<br />
FD300+Mertect 340F<br />
FD300+thiamethoxam<br />
FD300+Thiram<br />
FD300+Trigard<br />
FD300+Vangard<br />
Rovral 4F<br />
Thiram<br />
l
Health assay: % <strong>Seed</strong> infected with Botrytis<br />
% seed with Botrytis spp.<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Non-trt seed, non-inoc<br />
Non-trt sd, inoc flat<br />
b<br />
AgriCoat 711A<br />
j<br />
AgriCoat 800A<br />
j<br />
Apron+Maxim+A14635<br />
a<br />
Coronet 200 ml<br />
i<br />
Coronet 400 ml<br />
i<br />
bc<br />
Farmore D300<br />
fg<br />
FD300+Actigard<br />
cd<br />
FD300+Mertect 340F<br />
ef<br />
FD300+thiamethoxam<br />
FD300+Thiram<br />
h<br />
de<br />
FD300+Trigard<br />
FD300+Vangard<br />
d<br />
Rovral 4F<br />
j<br />
l<br />
Thiram<br />
g<br />
l
Health assay: % <strong>Seed</strong> infected with Aspergillus<br />
% seed with Aspergillus spp.<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Non-trt seed, non-inoc<br />
cde<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
h<br />
AgriCoat 800A<br />
bcd<br />
h h h<br />
Apron+Maxim+A14635<br />
Coronet 200 ml<br />
Coronet 400 ml<br />
ab<br />
Farmore D300<br />
g<br />
FD300+Actigard<br />
def<br />
FD300+Mertect 340F<br />
bcd<br />
FD300+thiamethoxam<br />
FD300+Thiram<br />
g<br />
bc<br />
FD300+Trigard<br />
FD300+Vangard<br />
ef<br />
a<br />
Rovral 4F<br />
l<br />
fg<br />
Thiram
Health assay: % <strong>Seed</strong> infected with Penicillium<br />
% seed with Penicillium spp.<br />
20<br />
18<br />
16<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Non-trt seed, non-inoc<br />
Non-trt sd, inoc flat<br />
a<br />
AgriCoat 711A<br />
h<br />
AgriCoat 800A<br />
h<br />
bc<br />
Apron+Maxim+A14635<br />
Coronet 200 ml<br />
h<br />
Coronet 400 ml<br />
h<br />
ab<br />
Farmore D300<br />
efg<br />
FD300+Actigard<br />
FD300+Mertect 340F<br />
ab<br />
FD300+thiamethoxam<br />
ef<br />
FD300+Thiram<br />
fg<br />
FD300+Trigard<br />
d cd<br />
FD300+Vangard<br />
Rovral 4F<br />
g<br />
l<br />
Thiram<br />
de
% seed infested<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Non-trt seed, non-inoc<br />
Health assay: % <strong>Seed</strong> infested<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
AgriCoat 800A<br />
Apron+Maxim+A14635<br />
Coronet 200 ml<br />
Coronet 400 ml<br />
Farmore D300<br />
FD300+Actigard<br />
FD300+Mertect 340F<br />
FD300+thiamethoxam<br />
FD300+Thiram<br />
FD300+Trigard<br />
FD300+Vangard<br />
Rovral 4F<br />
Thiram<br />
Botrytis<br />
Aspergillus<br />
Penicillium<br />
l
Plant dry weight (grams, 35 d)<br />
Pythium assay: Plant dry weight (~35 d)<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Non-trt seed, non-inoc<br />
a<br />
e-h<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
h<br />
AgriCoat 800A<br />
gh<br />
c-g<br />
Apron+Maxim+A14635<br />
f-h<br />
Coronet 200 ml<br />
f-h<br />
Coronet 400 ml<br />
b-e<br />
Farmore D300<br />
d-h<br />
FD300+Actigard<br />
*<br />
ab<br />
FD300+Mertect 340F<br />
d-h<br />
FD300+thiamethoxam<br />
FD300+Thiram<br />
*<br />
bcd<br />
c-g<br />
FD300+Trigard<br />
abc<br />
FD300+Vangard<br />
*<br />
gh<br />
Rovral 4F<br />
b-f<br />
l<br />
Thiram<br />
l
Pythium seedling blight assay<br />
Non-treated seed in noninoculated<br />
medium<br />
AgriCoat 711A<br />
Non-treated seed in<br />
inoculated medium
Rhizoctonia assay: Plant dry weight (~35 d)<br />
Plant dry weight (grams, 35 d)<br />
5<br />
4.5<br />
4<br />
3.5<br />
3<br />
2.5<br />
2<br />
1.5<br />
1<br />
0.5<br />
0<br />
Non-trt seed, non-inoc<br />
a<br />
ef f<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
ef<br />
AgriCoat 800A<br />
Apron+Maxim+A14635<br />
b<br />
bc<br />
Coronet 200 ml<br />
bc<br />
Coronet 400 ml<br />
bc<br />
Farmore D300<br />
cd<br />
FD300+Actigard<br />
*<br />
bc<br />
FD300+Mertect 340F<br />
cd<br />
FD300+thiamethoxam<br />
bc<br />
FD300+Thiram<br />
bc<br />
FD300+Trigard<br />
cd<br />
FD300+Vangard<br />
b<br />
Rovral 4F<br />
l<br />
de<br />
Thiram<br />
l
Pythium & Rhizoctonia: Plant dry weight<br />
Plant dry weight (grams, 35 d)<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Non-trt seed, non-inoc<br />
* Pythium ultimum<br />
* Rhizoctonia solani<br />
Non-trt sd, inoc flat<br />
AgriCoat 711A<br />
AgriCoat 800A<br />
Apron+Maxim+A14635<br />
Coronet 200 ml<br />
Coronet 400 ml<br />
Farmore D300<br />
FD300+Actigard<br />
*<br />
*<br />
FD300+Mertect 340F<br />
FD300+thiamethoxam<br />
*<br />
FD300+Thiram<br />
FD300+Trigard<br />
*<br />
FD300+Vangard<br />
Rovral 4F<br />
Thiram<br />
l
Summary<br />
• <strong>Seed</strong>borne fungi:<br />
• Best efficacy from AgriCoat 711A & 800A, Coronet, &<br />
Rovral 4F against Botrytis, Aspergillus, & Penicillium<br />
• Soilborne damping-off pathogens:<br />
• Pythium = Best efficacy from Farmore D300 +<br />
Mertect 340F or Vangard WG<br />
• Rhizoctonia = none with great efficacy, many with<br />
moderate efficacy<br />
• Organic treatments had no efficacy<br />
• Need multiple modes of action<br />
• 2008 WSDA registration for Coronet on onion seed
Acknowledgements<br />
AgriCoat<br />
LLC, BASF Corp.,<br />
Syngenta<br />
Crop Protection<br />
Christianson Endowment<br />
<strong>Seed</strong> companies, growers, field reps<br />
Mike Derie, Derie,<br />
Louise Brissey, Brissey<br />
Barbara Holmes, Emily Gatch, Gatch<br />
Megan Twomey, Twomey,<br />
Carrie Miller<br />
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