2018	Montana Seed Potato
Disease Management Guide
Jess ica Rupp, Nina Zidack, and Barry Jacobsen

The state of Montana dedicates approximately 11,000 acres to the production of the nation’s finest
seed potatoes. Many products are available to help manage diseases affecting seed potato. The following tables represent a quick reference guide concerning many products for seed treatments, disease management, comparisons among products, and disinfectants used for potato handling and storage for your convenience. For guidelines concerning viral diseases, please see the Montana  Seed Potato Viral Disease Management Guide. Additional publications available: Bacterial and Fungal Diseases of Potato and their Management, Montana Seed Potato Late Blight Quick Reference Guide, and Late Blight for Gardeners. Publications coming soon: Biopesticides for Potato Production. For more information, please visit msuextension. org/pspp or montanaspud.org . Please check these websites periodically for weather station updates, new information, alerts, and new factsheets. Follow MtExtPSPP on Twitter for updates. Products listed here are for educational purposes only and do not constitute an exhaustive list. Please consult product labels and cdms.net. Information about FRAC group can be found at frac.info. If you have any additional questions or concerns please call Jessica at 406-404-0789 or Nina at 406-994-3150.

2018 Montana Seed Potato Disease Management Guide
Active

Disease

Aerial Stem Rot

Ingredient (FRAC
Group)

Copper hydroxide

Cymoxanil 27+

Product/ Rate		PHI days

See product labels. Use at highest label rate. See table on disinfectants.
Tanos, 8 oz/acre

Comments

Use with/without Mancozeb following hail event.

48 oz/acre maximum per cropping cycle. 72 oz/acre

famoxadone 11

/application. See product label.

14	maximum per 12 month period. Tank mix or alternate
with copper and/or Mancozeb.

Sodium/ calcium hypochorite

Bacterial Ring Rot or Black Leg

quaternary ammonium compounds
peroxyacetic acid
hydrogen peroxide
formaldehyde
phenol
copper quinolate
iodine compounds

See product labels. Use at highest label rate. See table on disinfectants.

Use only approved tissue culture derived nuclear stocks. Wash and disinfect cellars, air duct pipes, & all handling/cutting equipment with soapy water, then with disinfectant, keeping wet for 10-15 minutes.
Disinfect cutter between each lot. Do not use old sacks. Do not allow any off-farm trucks to be cleaned out on premises. When possible, have truck prewashed with soapy water followed by Quaternary ammonium compound. Use quaternary ammonia disinfectant foot baths. Work with potato lab on any suspected infections.

Disease		Ingredient FRAC Group

Product/ Rate	PHI day

Comments

Bacterial Soft Rot

Same as above.

Chlorine dioxide

sodium/ calcium hydrochlorite

mixtures of peroxyacetic acid and hydrogen peroxide

See product labels. Use at highest label rate.
See table on disinfectants.

Avoid harvest at greater than 65-75F, especially when wet. Have good skin set before harvest (10-14 days post vine kill). Provide protection from sun scald of harvested tubers. Tarp loads if long exposure. Remove symptomatic or damaged tubers before binning . Do not drop potatoes farther than 6-8" during harvest, handling, and binning. Place in disinfected storage with "clean" equipment. Allow for suberization for 10-14 days @50- 55F, aerations with no moisture condensation. If frost damage or signifiicant damage from dry soil-seperate if possible-consider use of Biosave, Oxidate, SaniDate, StorOx, JetOxide, Jet-ASg. Do not use BioSave with other products. If possible, wait to harvest so sympotomatic tubers are obvious. Pile seperately-use as shallow a pile as possible, Use dry air to dry out as fast as possible. Use lower temperatures get to 38-40F as fast as possible

Pre-eme rg ence 

Azoxystrobin 11

Quadris, Apply infurrow 0.4-0.82 fl oz /1000 row ft
Vertisan, Apply

n/a

Plant disease-free seed, several products: Quadris Ridomil Gold SL,

Penthiopyrad 7

infurrow 0.7-1.6 fl oz/1000 row ft

n/a	max rate/A=24 oz

Fluapyroxad 7+
pyraclostrobin 11

Priaxor, Apply infurrow at 0.48-0.6 fl oz/1000 row ft

n/a

Apply again foliar (4-8 0z/A) when plants are 6-12 inches and again before row closure

Post-eme rg ence 

Azoxystrobin 11	Quadris Flowable ,
6.0-15.5 fl oz/acre

14	Apply Quadris prior to disease and continue disease control 7-14 day interval. Rotate with other MOA.

Black Dot

Azoxystrobin 11+
Chlorothalonil M5
Azoxystrobin 11+
Difenoconazole 3

Quadris Opti , 1.6 pts/acre

Quadris Top, 8-14 fl oz/ acre

14	Apply Quadris Opti when plants are 6-12”, Do not apply more than 1.5 lb ai of azoxystrobin per acre per year.

14

Apply Quadris Top prior to disease and continue disease control 7-14 day interval. Rotate with other MOA.

Pyraclostrobin 11	Headline/Headline
SC, 6-9 fl oz/acre
Dithane F-45 : 1- 2 lb/acre, Manzate

3	Apply Headline when plant are 6-12', Max product rate per season 72 fl/oz/acre

Mancozeb M3

Chlorothalonil M5

Prostick: 1-2 lbs/acre,
Penncozeb: 0.5- 2lb/acre
Bravo : 2-1/2 to 4-1/4 pints/acre, Bravo
Weatherstik: ¾ pt/acre, Bravo ZN 1 1/8 pt/acre, Equus
DF: 0.7 lb/acre then 0.9-1.36 lb/acre,
Equus 720 SST:
0.75, then 1-1.5
pt/acre, Echo 720:
0.75, then 1-1.5
pts/acre, Initiate
ZN: 1.125, then 1.5-
2.25 pt/acre,
Orondis Opti B , 0.75, then 1.5 pt/acre

3	Do not exceed more than 11.2 lb ai/season

Many formulations. Follow labels for specific rates and
7	spray intervals. Do not apply more than 15 pints of Orondis Opti B (11.25 lb ai) per acre during each growing
season.

Disease

Active
Ingredient (FRAC
Group)

Product/ Rate		PHI days

Comments

Difenoconazole 3

Top MP, 5.5-7 fl oz/acre

Vertisan, see label,

14	Use no more than 2 consecutive sprays, rotate to another mode of action. Do not apply more than 28 fl. oz./A
No more than 2 consecutive applications no more than

Penthiopyrad 7

Fluapyroxad 7+

14- 24 fl oz/acre	7
Priaxor Xemium,

28 oz/A /season No more than two consecutive applications and no more than 72 fl oz/season/A
No more than two consecutive applications and no more

Pyraclostrobin
11
Azoxystrobin

see label, 4-8 fl.
oz/acre

7	than 3 applications (4-8 oz/A) or 24 oz/season

Black dot

11+
Benzovindiflupyr 7
Pyraclostrobin 11+ Metiram M3

Zoxamide 22+

Elatus , 0.34-0.5 oz/1,000 ft

Cabrio Plus , 2-2.9 lb/acre

Zing!, 24-34 fl

n/a	Apply in-furrow at planting. No more than 9.5 oz/acre banded. See label.

14	No more than two consecutive applications of group 11 fungicide , No more than 17.4 lbs/acre/season
Apply on a preventative schedule. Use the maximum labeled rate at row fill. Do not make more than 2 sequential applications before alternating with a

Chlorothalonil
M5

oz/acre	7

fungicide that has a different mode of action. Do not
make more than 8 applications or apply more than 1.52 lb zoxamide and 8.88 lb chlorothalonil per acre per season.

Early Blight
Late

Metconazole 3	Quash, 2.5-4 oz/acre	1	No more than 4 applications per season, no more than 16
oz, no more than 2 sequential applications
Use adequate Nitrogen for yield objectives. Use P day forecasting system to initiate fungicide applications: uspest.org

Blight	Eliminate cull piles before crop emergence, plant disease-free seed, control volunteers, scout fields for symptoms, use weather based late blight forecasting models uspest.org and montanaspud.org

14

Early Blight: For a 7 day application schedule, use 6.2 fl

Azoxystrobin 11

Azoxystrobin

Quadris Flowable , 6-15.5 fl oz/acre

oz/acre. For a 14 day application use 12 oz/acre. Late Blight: For a 7-day schedule apply Quadris at 12.0 fl oz/acre. Use no more than 2.88qt/a per season. Alternate away from Group 11 fungicides to manage resistance.

11+
chlorothalonil M5

Quadris Opti , 1.6 pt/acre

14	Alternate away from Group 11 fungicides to manage resistance. Use no more than 3 gal/a per season

Begin applications prior to disease development, continue on a 7-14 day interval. No more than 2

Early Blight

Azoxystrobin+ difenoconazole 3

Bacillus

Quadris Top, 8-14 fl oz./acre

Life Gard WG, 1-

consecutive applications. The addition of a
14	spreading/penetrating type adjuvant such as a non-ionic
based surfactant or crop oil concentrate or blend is recommended.
NOP and OMRI Certified, may be applied up to 5 times per crop cycle. Apply in an alternating or tank mix program with labeled fungicides as part of a disease

and Late Blight

mycoides isolate
J

4.5 fl oz /acre.	0

Bravo ZN: 1 1/8, then 1 ½ to 2 ¼ pts/acre, Bravo
Weather Stik 0.75, then 1-1.5 pts/acre,
Equus 720 SST: 0.75, then 1.0-1.5

management program.
Mix only with fungicides having label instructions that do not prohibit such mixtures. See label for specific rates.

Chlorothalonil M5

pt/acre Equus DF: 0.7, then 0.9-1.36
lbs/acre, Echo 720 :
0.75, then 1-1.5
pts/acre Initiate
720: 0.75, then 1-1.5
pts/acre, Initiate
ZN: 1 1/8, then 1 1/2 to 2 1/4 pts/acre

7	Many formulations, follow labels for specific rates and spray intervals

Disease

Active
Ingredient (FRAC
Group)
Cymoxanil 27

Product/ Rate		PHI days

Early blight: Tanos,

Comments

+ famoxadone 11

6 fl oz./acre, Late blight: 6-8 fl oz/acre

14	Mix with M5 group fungicide, consult label

Fenamidone 11	Reason, 5.5-8.2 fl oz	14	30 day PHI for wheat, 1 year all other crops. Do not
exceed 24.6 oz/season

Fluoxastrobin 11

Pyraclostrobin 11

Pyraclostrobin 11+metiram M3

Evito: Early blight: 2-3.8 fl oz, Late blight: 3.8 fl oz,
Aftershock: Early blight: 2.0- 3.8 fl oz, Late blight 3.8 fl oz

Headline Early blight: 6-9 fl oz, Late blight: 6-12 oz
Cabrio Plus Early Blight 2-2.9 lb/acre,
Late Blight 2.9 lbs/acre

7	Do not exceed 22.8 oz/season

3	Do not exceed 2.25 qt/a per season

14	No more than 2 consecutive applications. No more than
17.4 lbs/season

Metaconazole 3	Quash Early Blight
only: 2-4 oz

1	No more than 2 consecutive applications. No more than 16 oz/A/season

Early Blight
and Late Blight

Fluapyroxad 7+ Pyraclostrobin 11

Trifloxystrobin 11

Priaxor Early Blight and Late Blight 4-8 oz/A
Gem 6-8 oz , Gem 500SC 2.9-3.8 fl oz
use highest rate for late blight

1	No more than two consecutive applications and no more than 3 applications (4-8 oz/A) or 24 oz/season

7	Do not exceed 48 oz (23 fl oz-Gem 500SC)/ season

Boscalid 7	Endura 2.5-4.5 oz	30	Early Blight only: No more than 2 sequential
applications, no more than 4 applications/season

Maneb M3

Maneb 80 WP- 1.5
-2.0 lb Manex 4F
1.2- 1.5qt

3	Do not exceed more than 11.2 lb ai/season

Mancozeb M3

Dithane F45 : 1- 2 lb/acre, Manzate : 0.4-1.6 fl oz/acre,
Penncozeb: 0.5- 2lb/acre

3	Do not exceed more than 11.2 lb ai/season

Mandiproamide 40+
Difenoconazole 3

Difenoconazole

Revus Top, 5.5-7.0 fl oz/acre

Top MP, 5.5-7 fl

Use primarily for Late blight. No more than 2 consecutive applications. No more than 28 fl oz/season

14

No more than 2 consecutive applications. No more than

3	oz/acre	14

28 fl oz/season Maybe tank mixed with Omega for late
blight

Pyrimethanil 9	Scala, 7 fl oz	7

7

Early Blight only: Does not control late blight –use in combination with a class M, 7 or 30 material

Fluopyram 7+pyrimethanil 9

Luna Tranquility, 8-11.2 fl oz/acre

Early Blight only: No more than consecutive applications, no more than 43.6 fl oz/A (ground application) or 33.6 fl oz/A (aerial application)

Disease

Active
Ingredient (FRAC
Group)

Product/ Rate		PHI days

SuperTin 4L: 4- 6
floz, SuperTin 80 WP: rate dependent

Comments

Do not use more than 18 oz/season SuperTin4L or 11.25

TPTH-
triphenyltin hydroxide 30

Zoxamide 22+

on method of application, see label, Agri Tin 80WP:
2.5-3.75 oz dry oz/acre, rate dependent on method of application

7
and 21

oz/ season of 80WP formulations. Do not use with emulsifiable pesticides or MH30. Some phytotoxicity to Superior and Norland varieties. Note 24 hr reentry period. May be mixed with maneb or mancozeb products for improved early blight control

Do not exceed 12lb/season Primarily for late blight. Note

Mancozeb M3	Gavel , 1.5-2.0 lb	3

field workers should be advised that this fungicide is
dermal and oral sensitizer

Early Blight
and Late

Chlorothalonil M5

Orondis Opti , 0.6 pts/acre then 1.125 pts/acre

7	Do not apply more than 15 pints of Orondis Opti B (11.25 lb ai) per acre during each growing season.

Blight

Metiram M3	Polyram, 1.5-2.0 lb	14	No more than 14 lb/ season-do not feed to livestock

Zoxamide 22 + Chlorothalonil M5

Zing!, 32-34 fl oz/acre

Apply on a preventative schedule. Use the maximum labeled rate at row fill. Do not make more than 2 sequential applications before alternating with a fungicide that has a different mode of action. Do not make more
7	than 8 applications or apply more than 1.52 lb zoxamide and 8.88 lb chlorothalonil per acre per season. Excellent
for late blight, can be used in place of standard protectants when disease pressure is high. Foliar applications of these products can be more effective in reducing the tuber blight phase of late blight than standard protectants.

Penthiopyrad 7	Vertisan, 10-24 oz	7	Early blight only: No more than two consecutive
applications and no more than 72 fl oz/season/A

Cymoxanil 27	Curzate , 3.2 fl
oz/acre
Cyazofamid 21	Ranman, 1.4-2.75 fl oz

Dimethomorph

14	Do not use alone, mix with FRAC M3, M5, 30 protective fungicide
7	No more than 27.5 fl oz/season. Note for crops not on label 30 day limit before planting
Tank mix with M class fungicide. Do not mix with

15	Forum, 4-6 oz	4
Ametoctradin

mefenoxam or metalaxyl. Do not exceed 30 oz/season.
May be used after vine kill to prevent tuber infection

45 +
Dimethomorph 15

Zampro, 11-14 oz	4	Maximum 42 oz per season

Late Blight only

Propamocarb hydroxide 28
Zoxamide 22 + Chlorothalonil M5

Previcur Flex , 0.7-
1.2 pt

Zing!, 32-34 fl oz/acre

14	Tank mix with M class fungicide. No more than 6 oz/season

Apply on a preventative schedule. Use the maximum labeled rate at row fill. Do not make more than 2 sequential applications before alternating with a fungicide that has a different mode of action. Do not make more
7	than 8 applications or apply more than 1.52 lb zoxamide and 8.88 lb chlorothalonil per acre per season. Excellent
for late blight, can be used in place of standard protectants when disease pressure is high. Foliar applications of these products can be more effective in reducing the tuber blight phase of late blight than standard protectants.

Fluazinam 29	Omega, 5.5 fl oz	14	Tank mix with M class fungicide. No more than 3.5
pt/season

Mandipropanid 40

Revus , 5.5-7.0 fl oz	14	Do not apply more than 28 fl oz/A/season

Disease

Active
Ingredient FRAC Group

Product/ Rate

PHI	Comments
days

Rhizoctonia stem canker and black

Azoxystrobin 11	Quadris, 0.4-0.8 fl
oz/1000 row ft
Azoxystrobin

Apply in-furrow at planting. Will also control Silver Scurf and Black dot. See seed treatment label for Dynasty

scurf -
infurrow

11+
Benzovindiflupyr 7

Elatus , 0.34-0.5 oz/1,000 ft

Apply in-furrow at planting. Nore more than 9.5 oz/acre banded. See label. Also effective against Black Dot

PCNB 14	Blocker 10 G, 1.65
lb/1000 row ft

Blocker 4F, 5.2 to

Apply in-furrow over the seed piece at planting in 8.5 inch band
Apply in-furrow for control of common scab. Do not

Seed
Treatments Please See the 2016
Seed
Treatment Quick

PCNB 14

Pyraclostrobin 11

Flutolanil 7

10.4 fl oz/1,000 ft row

Headline 4-8 fl oz/1000 row ft
Moncut 70-F, 0.71- 1.1lb

spray a PCNB within 12 months of previous application.
See label.

Apply in-furrow at planting

Apply in-furrow over the seed piece at planting in 4-8 inch band- Use a minimum of 3 gal/a water

oz/1000 row ft

Reference Guide

Penthiopyrad 7	Vertisan, 0.7- 1.6 fl

max rate/A=24 oz

Fluapyroxad 7+ Pyraclostrobin 11

Mefanoxam 4

Mefenaxam 4 + Chlorothalonil M5

Priaxor, 0.48-0.6 fl oz/1000 row ft

Ridomil Gold EC,
0.42 oz/1000 row ft, Ultra Flourish 0.84 fl oz/1000 row ft
Ridomil Gold	14
Bravo , 2.5 pts/acre

No more than 24 fl oz or Priaxor may be applied per season

Use a minimum of 3 gal/a water in 6-8 inch band over seed piece. Apply at planting with Quadris=Quadris Ridomil Gold (0.82 fl oz/1000 ft row)

At total of 3 applications at 14 day intervals starting at flowering

Pythium leak and Pink Rot

Mefanoxam 4 + mancozeb M3

Cyazofamid 21

Ridomil Gold MZ,
2.5 lbs/acre
Ranman, 0.42 fl oz/1000 row ft (in- furrow), 2.75 fl oz at layby

3	At total of 3 applications at 14 day intervals starting at flowering

0	Use full label rate

Apply in-furrow with Ultra Flourish and with foliar

Phosphorous acid P7

Phostrol , See label	0

sprays. Start at tuber initiation use 3 applications at 14 day interval. May be used postharvest 12.8 fl oz/ton in 0.5 gal/ton

Boscalid 7	Endura, 5.5-10 oz	30	1-2 applications staring at 1st flower. Can be used to
replace early blight spray
1-2 applications staring at 1st flower. Must combine with

Fluazinam 29	Omega, 5.5-8.0 fl oz	14

M class fungicide to control early blight. This is a very good late blight fungicide. Tank mix with Top MP, chlorothalonil, mancozeb to control early blight
NOP and OMRI Certified, may be applied up to 5 times per crop cycle. Apply in an alternating or tank mix

White Mold

Bacillus
mycoides strain J

Life Gard WG, 1-
4.5 fl oz /acre.

0	program with labeled fungicides as part of a disease management program.
Mix only with fungicides having label instructions that do not prohibit such mixtures. See label for specific rates.

Fluopyram 7+
pyrimethanil 9

Iprodione 2

Luna Tranquility,
11.2 fl oz
Rovral 50 WP 4F:
2 pts/acre, Nevado : 2 pts/acre

7	1-2 applications staring at 1st flower. Can be used to replace early blight spray

14	2 applications staring at 1st flower.

Disease

Active

Ingredient (FRAC
Group)

Thiophanate-

Product/ Rate		PHI days

Topsin M 75 WP,

Comments

Make first application at row closure with subsequent

methyl 1

1-1.5 lb/A or 20-30
oz of 4.5 FL

21	applications 7-14 days later

White Mold

Penthiopyrad 7	Vertisan, 14-24 fl
oz

7	Disease suppression only, Treat at 100% bloom, again 14 later, no more than 72 fl oz./acre/year

Coniothyrium minitans

Contans, 1-4 lbs/acre

0	Apply in fall (preferred) or spring- incorporate lightly

Metconazole M3	Quash, 4.0 oz/acre	1	No more than 4 applications per season, no more than
16 oz, no more than 2 sequential applications

Fusarium D ry rot- storage

Pseudomonas	Biosave	0
syringae

Apply with 1-2 qt/ton of water. Avoid bruising Note ~ 50% of isolates in MT are resistant to thiabendazole (Mertect). However combinations of
BioSave with 0.42 oz/ton Mertect 340F have given the best results.

Scab

Our trials have shown the Blocker as applied for Rhizoctonia or Maxim MZ seed treatment plus Quadris applied in-furrow will give partial control. Be sure that soil moisture is greater than 80% field holding capacity from tuber set through bulking. Use resistant varieties where possible. Integrated management is critical

	Azoxystrobin		
Silver	11+	Elatus, 0.34-0.5	
Scurf	Benzovindiflupyr	oz/1,000 ft	
	7		

Powdery Mildew

Difenoconazole 3

Top MP, 5.5-7 fl oz/acre

Apply 7-14 day interval, no more than two consecutive applications
Apply in-furrow at planting.  Nore more than 9.5 oz/acre banded. See label. Also effective against Black Dot

PESTICIDE USE: Pesticide usage suggestions provided in MSU Extension materials are intended to
serve only as a guide and are published for educational purposes. If any suggestions conflict with a product label, follow the product label instructions. Read and follow all product labels carefully.

Disclaimer: This is not an endorsement of any of the products listed here. Many other products exist. Please consult product labels for rates, proper intervals, and recommendations.

2017 Potato Seed Piece and In- Furrow Treatment Guide

Active Ingredient IRAC/ FRAC Group

Product/ Rate	Comments

Imidacloprid 4

Admire Pro , 0.17-0.35 fl oz/cwt

Apply as diluted spray for the pest suppression of aphids, Colorado potato beetle, flea beetles, leafhoppers, potato psyllids, and wireworms.

Clothianidin 4	Belay , 4.0-6.0 fl oz/acre

Apply in-furrow for the pest suppression of aphids, Colorado potato beetle, flea beetles, leafhoppers, potato psyllids, and wireworms.

Pentachloronitrobenzene (PCNB) 14

Blocker 10 G, 1.65 lbs/1,000 row ft

Apply in-furrow with 8.5" band. See label. PHI=45 days For the control of Stem Canker and Black Scurf.

0.19-0.27 fl oz/cwt

Fludioxonil 12 + Thiamethoxam 4	Cruiser Maxx Potato,

Rate dependent on seeding rate, see label.

Cymoxanil 27 + mancozeb M3	Curzate , 0.25-1 fl oz/cwt

Dithane F-45 , 1.6-2.5

Apply as slurry or concentrated mist for control of late blight. Excellent where seed borne late blight is suspected-use with maneb or mancozeb.

Apply as a slurry for control of late blight,

Mancozeb M3

oz/cwt

Fusarium, Common scab, Rhizoctonia shoot
blight and Silver scurf.

Azoxystrobin 11	Dynasty , 0.10-3.75 per 100 lbs of seed

Apply as slurry for the supression: Black Scurf, Black Dot, Stem Canker, Protection: Silver Scurf. Excellent for seed-borne Rhizoctonia, Silver Scurf, and Black dot. Some soil activity, not as good as in-furrow Quadris. Note- Still labeled, but no longer sold for potato.

Azoxystrobin 11	Equation, 5.8-8.7 fl oz/acre	Apply in-furrow for the control of Black scurf,
Silver scurf, and Black dot. See label.

Penflufen 7 + Prothioconazole 3

Ernesto Silver, 0.31 fl oz/cwt

Apply as diluted spray/slurry for the supression of Rhizoctonia dieases and dry rot. Add mancozeb for better Fusarium control.

thiophanate-methyl 1, mancozeb M3, and cymoxanil 27

Evolve , 0.75 lbs/100 lbs

Apply as dust to cut or single drop seed for the suppression of late blight. Do not attempt to rescue seed. Also for the suppression of Dry rot, Black scurf, and Silver scurf.

Pyraclostrobin 11	Headline EC, 0.4-0.73 fl oz/1,000 ft row

oz/1,000 ft row

Pyraclostrobin 11	Headline SC, 0.4-0.73 fl

Koverall , 1.25 lb/50 gal

Apply in-furrow for the control of Rhizoctonia diseases.
Apply in-furrow for the control of Rhizoctonia diseases.

Apply as slurry, for the suppression of Dry rot,

Mancozeb M3

water

Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

2017 Potato Seed Piece and In-Furrow Treatment Guide cont.

Active Ingredient (FRAC Group)

Product/ Rate	Comments

Maneb/ mancozeb M3 Mancozeb M3

Mancozeb M3

Many products, rate varies

Manzate Flowable , 1 qt/50 gal

Manzate Prostick, 1.25 lbs/50 gal water

Good for seed borne scab. Good fungicide resistance management partner for fludioxonil and cymoxanil.
Apply as slurry, for the suppression of Dry rot, Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

Apply as dust, for the suppression of Dry rot, Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

Fludioxonil 12	Maxim, 8.0 fl oz/cwt

Apply as dust to cut or single drop seed for supression of Fusarium, Stem canker, Black scurf, and Silver scurf.

Fludioxonil 12	Maxim MZ, 0.5 lb/cwt

Apply as dust to cut or single drop seed. Excellent control of Fusarium seed piece decay, Scab, Silver scurf, Seed-borne late blight.

Fludioxonil 12

Maxim 4S , 0.04-0.08 fl oz/cwt

Apply liquid to cut or single drop seed for suppression of Fusarium, Stem canker, Black scurf, and Silver scurf. ***DO NOT USE UNLESS MANCOZEB OR MANEB IS
ADDED*** Resistance has been reported. As a seed producing state we do not want to ship Fusarium resistant to this important fungicide.

Flutolanil 7	Moncut 70 DF, 0.79-1.18 fl oz/1,000 row ft

Apply in-furrow, see label for row spacing.

Manozeb M3 +Flutolanil 7	Moncoat MZ, 0.75-1
lb/cwt

pints/acre

Fluazinam 29	Omega 500 F, 1.5-3.0

Mancozeb M3	Penncozeb 80 WP, 1.25 lbs/50 gal water

Apply as dust. Excellent seed piece treatment will provide control of Fusarium and Rhizoctonia seed piece decay, Scab and Silver scurf.

Apply in-furrow for the suppression of powdery scab. See label.

Apply as slurry, for the suppression of Dry rot, Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

Mancozeb M3	PSP, 1 lb/cwt

Apply as dust, for the suppression of Dry rot, Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

Mancozeb M3	PSP+bark, 1 lb/cwt

Apply as dust, for the suppression of Dry rot, Common scab, Silver scurf. Reduces the spread of late blight. Seed dip.

Fluxapyroxad 7 + Pyraclostrobin 11

Priaxor, 0.48-0.6 fl oz/1,000 row ft

Apply in-furrow for the suppression of Rhizoctonia diseases.

2016 Potato Seed Piece and In-Furrow Treatment Guide cont.
Active Ingredient (FRAC Group)	Product/ Rate	Comments

Azoxystrobin 11	Quadris, 0.4-0.6 fl oz/1,000 row ft

Quadris Ridimil Gold,

Apply in-furrow for the control of black scurf and silver scurf.

Apply in-furrow for the control

Azyoxystrobin 11 + Mefenoxam M3

Cyazofamid 21

0.82 fl lz/ 1,000 row ft

Ranman 400 SC, 1.42 fl oz/1,000 row ft (Lay by:
2.75 fl oz/acre in 20 gal spray solution)

of Rhizoctonia diseases,
pythium leak, and pink rot.
Apply in-furrow of control of pink rot apply at lay-by for suppression of late blight, pink rot, and Pythium. Use rotational modes of action.
See label.
Apply in-furrow or with dry

Mefenoxam M3	Ridimil Gold SL, 0.82 fl oz/1000 row ft

Roper DF Rainshield,

fertilizer. For post-harvest control of pink rot and Pythium leak.
Apply as slurry, for the suprresion of : dry rot,

Mancozeb M3

1.25 lbs/50 gal water

common scab, silver scurf.
Reduces the spread of late blight. Seed dip.

row ft

Azoxystrobin 11	Satorim, 0.4-0.6 fl oz/1,000

Serenade Soil , 2-6

Apply in-furrow for the control of black scurf and silver scurf.
Apply in-furrow for use against Rhizoctonia, Pythium, Fusarium, Verticillium,

Bacillus subtilis

qts/acre

Phytophthora, and Erwinia spp. Be mindful of tank mix,
as these are living organisms. See label.
Apply as slurry to cut or single

Fludioxonil 12	Spirato 40S , 0.5 lb/cwt

Thiophanate-methyl 1	ST-Methyl 540 FS, 0.5-
0.7 fl oz/cwt

drop seed for supression of Fusarium, stem canker, black scurf, and silver scurf.
Apply as a slurry for the supression of Black scurf, stem and stolon canker, silver scurf, and dry rot. See label.

Trichoderma harzianum	T-22 , 0.5-3.0 oz/cwt	Biological, Apply as a slurry or in-furrow. See label.

Information on fungicide controls and their effectiveness for control of early blight, late blight,
Pythium leak, Phytophthora pink rot, and white mold
E= Excellent control, G=Good control, F=Fair control, P=Poor control, N= no control

Type

Active
Ingredient

Name

Late	Early	Pythium	Pink	White
Blight	Blight	Leak	ro t	Mold

Fungicide

Protective

2017 Potato Seed Piece and In-Furrow Treatment Guide cont.
Active Ingredient (FRAC 

Group)

Product/ Rate

Comments

Imidacloprid 4, Thiophanate- methyl 1, and mancozeb M3

Tops MZ Gaucho , 0.75 lb/100 lb

Apply as dust to cut or single drop seed for the suppression of late blight. Do not attempt to
rescue seed. Also for the suppression of Colorado potato beetle, flea beetle, potato leaf- hopper, psyllids, wireworms, dry rot, black scurf, and silver scurf. Good seed treatment for seed-borne, but not soil-borne Rhizoctonia and scab. Due to resistance, it may not be effective for Fusarium or Silver Scurf.

Azoxystrobin 11	Quadris, 0.4-0.6 fl oz/1,000 row ft
Azyoxystrobin 11 + Mefenoxam 4	Quadris Ridimil Gold,
0.82 fl lz/ 1,000 row ft

Apply in-furrow for the control of black scurf
and silver scurf.
Apply in-furrow for the control of Rhizoctonia diseases, pythium leak, and pink rot.

	Bravo 720	G	G	N	N	P	
	Bravo Ultrex	G	G	N	N	P	
	Bravo Weather Stik	G	G	N	N	P	
	Bravo weather Stik						
Chlorothalonil	Zn	G	G	N	N	P	
	Bravo Zn	G	G	N	N	P	
	Echo 720	G	G	N	N	P	
	Echo 90 DF	G	G	N	N	P	
	Echo Zn	G	G	N	N	P	
	Dithane 75DF	G	G	N	N	N	
	Dithane Rainshield						
	NT	G	G	N	N	N	
	Maneb 75 DF	G	G	N	N	N	
Dithiocarbamate	Maneb plus Zinc	G	G	N	N	N	
	Manzate Flowable	G	G	N	N	N	
	Manzate Pro-Stik	G	G	N	N	N	
	Pencozeb 75DF	G	G	N	N	N	
	Polyram 80DF	G	G	N	N	N	
Triphenyltin hydroxide	Super-Tin 80 WP, 4L	
E	
E	
N	
N	
N	
	Agri Tin 80WP	E	E	N	N	N	
Benzamide	Gavel 75 DF	E	G	N	N	N	

Information on fungicide controls and their effectiveness for control of early blight, late blight, Pythium leak, Phytophthora pink rot, and white mold cont.

Name

E= Excellent control, G=Good control, F=Fair control, P=Poor control, N= no control

Type

Active
Ingredient

Late Blight

Early Blight

Pythium Leak

Pink ro t

White Mold

Gem	F-G	E	N	N	N	
Headline	F-G	E	N	N	N	
Tanos	E	E	N	N	N	
Reason 500SC	E	E	N	N	N	
Quadris	E	E	N	N	N	
Quadris Opti	F-G	E	N	N	N	
Evito 480 SC	P-F	E	N	N	N	
Ridomil Gold MZ	F-G	F	G	G	N	
Ridomil Gold/Bravo	F-G	F-G	G	G	N	
Ridomil Gold/Bravo L	F-G	F-G	G	G	N	
Metastar	P	N	G	G	N	
Ultra Flourish	P	N	G	G	N	
Endura	N	N	N	N	N	
Luna Tranquility	N	N	N	N	N	
Vertisan	N	G-E	N	N	P	
Priaxor	F-G	E	N	N	E	
Curzate DF	E	N	N	N	N	
Forum	E	P	N	N	N	
Omega 500F	E	P	N	N	G-E	
ScalaSC	N	G	N	N	N	
Previcur Flex	E	P	N	N	N	
Quash	N	G	N	N	G	
Ranman	E	N	N	E	N	
RevusTop	E	E	N	N	N	
Revus	E	N	N	N	N	
Crop-Phite	P	N	N	N	N	
Fosphite	P	N	N	N	N	
Phostrol	P	N	N	N	N	
Resist 57	P	N	N	N	N	
Topaz	P	N	N	N	N	

QoI,
Strobilurin, Group 11

Phenyl Amide

Fungicide

Systemic/
translaminar

Carboxamid-7

Various

Phophorus Acid Compounds

Disclaimer: This data was generated from previously undertaken field research. This does not
constitute a recommendation of any of these products over another. These products were ranked by their performance in the field under the conditions in which plants were grown. Many other sources exist evaluating these products and many others for their efficacy in treating early blight, late blight, Pythium leak, pink rot, and white mold. Please read labels carefully for the desired disease control guidelines.

2017 Late Blight Fungicides for Control compared at highest label rate Quick Reference Guide
For more information please see the 2016 Montana Seed Potato Late Blight Quick Reference Guide
E= Excellent control, G= Good control, F= Fair control, P= Poor control, N= no control, U= unknown Effectiveness	Mode of action

Fungicide

Chlorothalonil, many products

Mancozeb Maneb
metiram

Curzate Forum
Gavel

Omega
Previcur-Flex Phosporus acid
Several products
Ranman Tanos
Revus Top

TPTH
SuperTin, Agri Tin
Headline Gem
Quadris
Reason

Leaf

New

Stem

Tuber

ant	Curati

Anti-

Rain

Blight	growth	blight	Blight	Protect		ve	sporulant	
G	N	P	N	G	N	N	G	
G	N	P	N	G	N	N	F	
G	N	P	N	G	N	N	F	
G	N	P	N	G	N	N	F	
G	U	F	N	G	E	P	G	
G	U	F	F	G	P	G	G	
E	N	P	F	E	N	N	G	
E	N	P	G	E	N	N	G	
G	G	G	N	G	G	G	E	
P	P	P	G	P	N	U	G	
E	N	P	E	E	N	N	E	
G	U	F	N	G	E	P	G	
E	U	F	G	E	P	F	E	
E	N	E	E	G	N	E	F	
G-E	P-F	F	N	G	G	P	G-E	
G-E	P-F	F	N	G	G	P	G-E	
G-E	P-F	F	N	G	G	P	G-E	
G-E	P-F	F	N	G	G	P	G-E	

fastness

Type of
fungicide

Protective, Contact
Protective, Contact Protective, Contact
Protective, Contact
Translaminar
Translaminar
Protective, Contact
Protective, Contact
Systemic

N/A

Protective, Contact
Translaminar
Translaminar, protective, contact
Protective, Contact
Translaminar Translaminar Translaminar Translaminar

The 2016 Montana Seed Potato Late Blight Quick Reference Guide is available in print by request
and online at both msuextension. org/pspp and montanaspud.org . For a print copy, please send an email to jessica.rupp@montana.edu and include your name, address, and the number of copies you would like to receive.

2017 Disinfectants for Potato Handling and Storage Equipment
Type	Active ingredient	Products	Comments Chlorine generating products
Note: Chlorine has significant human inhalation problems-follow safety precautions!

Bleach	Sodium hypochlorite

Calcium	Calcium hypochlorite
hypochlorite

Chlorine dioxide	Chlorine dioxide

Many products available. Rate will depend on product. Concentrations will vary from 3.25- 12%

Many products available. Rate will depend on product label.

Oxine Sanitizer, SNiPER, EnviroCON, Clorodisys, CDG Solution 3000, and Purogene

Strong oxidizer (corrosive), rapidly inactivated by soil or organic matter, no residual activity. Water pH must be 4-8.

Strong oxidizer (corrosive), rapidly inactivated by soil or organic matter, no residual activity. Water pH must be 4-8. Can be applied directly to potatoes.

Less corrosive than bleach, no residual activity, water pH not as critical.

Non- chlorine gene rating products
Quaternary Ammonium,

Quaternary Ammonium products

Hydrogen peroxide/
Peroxyacetic acid products

benzalkkonium chloride, n-alkyl dimethyl benzyl ammonium chloride, N,N,-didecyl-N,N- dimethyl ammonium chloride, etc.

Hydrogen dioxide (hydrogen peroxide)

De-Bac, Virex, Roccal-D, AFBC, Breakthru, Micro Q64, Micro Q128, Pro- San, and many others.

StorOx, Oxidate, Jet Oxide, Jet Ag, SaniDate 12.0

Only slightly corrosive, relatively safe for humans when diluted, some residual activity, much less affected by organic matter or soil. Water pH not critical.

Can be applied directly to potatoes, no residual. Low corrosiveness. With use of heat JetAg can be used as fumigant in air system.

Iodine, Iodophores	Iodine, povidone iodine

Code Blue Iodine disinfectant and many others. Look for iodine in label name

Corrosive, will stain treated areas, some residual activity. Less affected by organic matter or water pH than bleach.

Phenol-
glutaraldehyde

Phenol- glutaraldehyde

Sporocidin, Hospiseptic Disinfectant Wex-cide, Birex, etc- look for Phenol in name

Warning: oral poison!

Formaldehyde	Formaldehyde	Many products available.	Potential human carcinogen! Follow
OSHA directions regarding exposure

Copper
quinolinolate

Copper 8 quinolinolate

Many products available. Purchase as generic chemical. ISK Biotech PQ-57, PQ-80

Good residual activity. May cause some staining.

The first step in disinfesting surfaces contaminated with potato residues and potential pathogens is to remove soil and  potato residues by washing with soapy water and scrubbing to remove heavy deposits of potato residue. This is an  important step since many disinfectants are inactivated by soil or organic matter and bacteria can live in the heavier  residues protected from disinfectants. The second step is to disinfect with a labeled disinfectant. It is important to keep all surfaces wet with the disinfectant solution for 10-15 minutes and to use the highest labeled rate of the disinfectant chemical.

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MSU’s Seed Potato Certification Website: montanaspud.org