Understanding Phosphorous Acid on Injury and...

Understanding Phosphorous Acid on Injury

and Uptake in Tubers Andy Robinson, Potato Extension Agronomist, NDSU / U of M

www.ag.ndsu.edu/potatoextension

Phosphorous Acid Applications

• Phosphorous acid applied to protect crop

from Pink Rot and Late Blight tuber rot.

– Applied foliar and direct on tubers going into

storage.

• When applied foliar growers often report

leaf burning especially if the crop is under

moisture, fertility, or disease stress.

2

Phosphorous Acid Applications

• Shown to be highly effective at controlling late blight and pink rot (Gudmestad).

• Also data indicates silver scurf control in storage.

• Not effective against soft rots, leak, Fusarium.

• There is potential for leaf burning especially if the crop is under moisture, fertility, or disease stress.

Gefu Wang-Pruski,PhD Tudor Borza, PhD

Evaluation of ConfineTM Residue in Field and Postharvest

Treated Tubers 2012

Wang-Pruski’s Conclusions

– Ion chromotograhy effective at quantifying

phosphite in tubers

– Post harvest application resulted in highest

levels of phosphites in cortex and tuber

– Rate response (10 pt/a applied 3x was better

than 2x)

– Concentrations: Cortex>medulla>skin

– Foliar treatments translocate to the tuber

(Gefu Wang-Pruski Ph.D, Tudor Borza Ph.D)

Avocado Growers

Preferred Treatment Methods

7

Current Application Use Patterns

Examples of treatments:

• Chemigation 4.8 L/a 2X

• Aerial 2.4 L/a 4-6X

• Aerial 3.3 L/a 2X chemigate 3.3 L/a 1X

• Aerial 3.3 L/a 3X

• Ground rig 3.3 L/a 1X

• Aerial 4.8 L/a 1X chemigated 4.8 L/a 1X

• None

• Many others…

Variation because growers are trying to reduce injury.

8

Picture of burn…

10

Efficacy and Injury

Injury

• Greenhouse trial (2014)

• Field trials (2014-2015)

Efficacy

• Lab testing for phosphite

• Challenge inoculation for pink rot

Spring 2013 Samples - Europhins Lab

Dr. Neil Gudmestad

Location Method Rate Pink rot (%) Phos acid

(mg/kg)

1 Linton Check 0 15.0 No test

2 Larimore Flown 4 X 2.4 L/a 1.3 89.7

3 Dawson Flown 1 X 4.8 L/a 1.3 62.9

Chemigation 1 X 4.8 L/a

4 Karlsruhe Chemigation 2 X 4.8 L/a 3.8 24.8

5 Park Rapids Flown 2 X 2.4 L/a 3.8 28.3





LSD p=0.05 7.1

Adjuvants

Can adjuvants

reduce injury

from phosphoric

acid?

14

WATER

WATER + SURFACTANT

15

North Dakota Adjuvant CompendiumFor other adjuvants: www.herbicide-adjuvants.com/

Fertilizer

AMS (Dry)AMS (liquid)

VariousVarious

$0.35 lb$6.00 gal

4 to 8.5 lb/A2 to 4 qt/A

28% UAN/Bulk Various $3.00 to 10.00 gal 2 to 4 qt/A

Nonionic Surfactant (NIS)

Activator 90APSA-80ChemSurf 90WetcitHypertonicInduceLiberate LeciTechPen-A-trate IIPrefer 90PreferenceProtyxR-11Surf-AC 910Tradition 93TranslateWet-Sol 99

LovelandAmwayUnited Suppl.Oro AgriCHSHelenaLovelandPrecision LabsWest CentralWinfieldPrecision LabsWilbur-EllisDrexelRosensUnited Suppl.Schaeffers

$30.00 gal$32.00 gal$32.00 gal$75.00 gal$31.00 gal$31.00 gal$40.00 gal$32.00 gal$32.00 gal$35.00 gal$100.00 g$27.00 gal$25.00 gal

$ - gal$38.00 gal$30.00 gal

0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.8% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v

0.125% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v0.25 to 0.5% v/v

NIS Approved for use in WaterSurfactants approved for use in bodies of water are: Activate Plus Agridex BroncPlusDryEDTClass Act NG Induce Level 7 Liberate L-TechPreference R-11 Top Surf X-77

Surfactant & Silicone

FreewayKineticSil-FactSilkinSpeedSur-PlusSylcoat

LovelandHelenaDrexelWinfieldPrecision LabsUnited Suppl.Wilbur-Ellis

$110.00 g$100.00 g$45.00 gal$96.00 gal$135.00 g$87.00 gal$122.00 gl

0.75 to 2 pt/100 gal 0.75 to 2 pt/100 gal0.75 to 2 pt/100 gal0.75 to 2 pt/100 gal

0.25 to 2 pt/100 gal0.5 to 2 pt/100 gal

0.75 to 2 pt/100 gal

Surfactant & AMS

Bronc PlusDryEDTClass Act NGClass Act FlexDeliverImpressive DBPowerhouseRe-DuceSurfate Ultra Surf AMSWheelhouse

Wilbur-EllisWinfieldWinfieldPrecision LabsRosensRosensHelenaLovelandUnited Suppl.CHS

$1.65 lb$13.00 gal$15.00 gal$14.00 gal

$1.25 lb$12.00 gal$12.00 gal$23.00 gal$10.00 gal$12.00 gal

10 lb/100 gal2.5% v/v

1 to 4 % v/v2.5% v/v2.25 lb/A

5 to 10 qt/100 gal1% v/v1% v/v

2.5% v/v2.5% v/v

AMS Replacement / Water Conditioning Agent (WCA)

CitronCut-RateQuest/RequestSpeedway

Farm DirectWilbur-EllisHelenaUnited Suppl.

$3.50 lb$2.50 lb

$22.00 gal$38.00 gal

2.2 lb/100 gal4 lb/100 gal

0.5% v/v0.5% v/v

AMS & WCA (AMS Replacement)

AllianceBronc MaxChoice W-MasterEnactSeQuel

WinfieldWilbur-EllisLovelandRosensHelena

$20.00 gal$24.00 gal$29.00 gal$25.00 gal$15.00 gal

1.25% v/v0.5% v/v0.5% v/v0.5% v/v

1 to 5 pt/100 gal

Surfactant & AMS Replacement (WCA)

FastrackFlameTransport Ultra

United Suppl.LovelandPrecision Labs

$28.00 gal$42.00 gal$39.00 gal

0.75% v/v0.5% v/v

0.25 to 0.75% v/v

Surfactant & AMS & AMS Replacement (WCA)

Bronc TotalTransport LpH

Wilbur-EllisPrecision Labs

$30.00 gal$20.00 gal

0.75 to 1% v/v0.5 % v/v

Acidic AMS Replacement (contains AMADS)

AMADS - Monocarbamide dihydrogen sulfate = urea + sulfuric acid

AduroBrimstoneET-4000FixateGun SmokeHel-FireImportJackhammer

WinfieldWilbur-EllisMK Ag ServiceCHSLovelandHelenaPrecision LabsWest Central

$32.00 gal$38.00 gal$31.00 gal$32.00 gal$40.00 gal$35.00 gal$37.00 gal$32.00 gal

4 pt/100 gal4 pt/100 gal4 pt/100 gal4 pt/100 gal4 pt/100 gal4 pt/100 gal4 pt/100 gal4 pt/100 gal

Basic pH Blend

AxonLinkageNewtoneQuad 7

CHSWest CentralWinfieldLoveland

$24.00 gal$24.00 gal$30.00 gal$22.00 gal

1% v/v1% v/v1% v/v1% v/v

Petroleum Oil Concentrate (POC/COC)

Agri-Dex HerbimaxWCS Crop OilPrime OilProtyx AerialR-WayROC Crop Oil

HelenaLovelandWest CentralWinfieldPrecision LabsRosensWilbur-Ellis

$24.00 gal$20.00 gal$14.00 gal$15.00 gal$21.00 gal

$ - gal$12.00 gal

1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A

0.5 pt/A1 to 2 pt/A1 to 2 pt/A

Crop (Soybean) Oil Concentrate

BeanOil Drexel $15.00 gal 1 to 2 pt/A

Methylated Seed Oil (MSO)

EmulateFire-ZoneMES-100MSO Leci-TechMSO UltraNoblePersist UltraPremium MSOSucceedSundance IISuperspread MSOUpland MSO

CHSHelenaDrexelLovelandPrecision LabsWinfieldJ.R. Simplot HelenaUnited Suppl.RosensWilbur-EllisWest Central

$22.00 gal$27.00 gal$16.00 gal$25.00 gal$26.00 gal$22.00 gal$20.00 gal$20.00 gal$19.00 gal$21.00 gal$24.00 gal$22.00 gal

1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A1 to 2 pt/A

High Surfactant Methylated Oil Concentrate (HSMOC)

Cide WinderDestiny HCDuceHot MESKixytSavvyWoodside

HelenaWinfieldHelenaDrexelPrecision LabsWest CentralCHS

$40.00 gal$38.00 gal $34.00 gal$29.00 gal$44.00 gal$36.00 gal$36.00 gal

1 to 1.5 pt/A1 to 1.5 pt/A1 to 1.5 pt/A1 to 1.5 pt/A1 to 1.5 pt/A1 to 1.5 pt/A1 to 1.5 pt/A

126

Greenhouse study

• Screened and evaluated adjuvants over

multiple runs

– Many adjuvants available today

• Carrier volume of 140 L/ha

• All treatments used 5.8 kg/ha phosphorus

acid (4.8 L/a Phostrol) + adjuvant

16

Greenhouse Testing

17

Field Study (2014)

• Commercial Russet Burbank field 2014 and

repeating some treatments in 2015

• RCBD with 4 replicates

• Treatments were various adjuvant combinations

• Application at dime-sized tuber and 14 days

after dime-sized tubers

• Estimated crop injury & biomass at 3 days after

treatment

• ANOVA with a LSD at p=0.05

19

20

Crop injury and estimated biomass 3 days after treatment applied on July

29, 2014 in Osage, MN.

Treatment Rate

1 Non-treated

2 Phostrol 2.4 L/a

3 Phostrol 4.8 L/a

4 Ingery MSO 6 fl oz/a

5 K-Tone 0.5% v/v

6 Phostrol + Inergy MSO 4.8 L/a + 6 fl oz/a

7 Phostrol + K-Tone 4.8 L/a + 0.5% v/v

8 Phostrol + Liberate

LeciTech 4.8 L/a + 0.5% v/v

9 Phostrol + Silkin 2.4 L/a + 0.25% v/v

10 Phostrol + Silkin 4.8 L/a + 0.25% v/v

11 Phostrol + Class Act NG 2.4 L/a + 2.5% v/v

12 Phostrol + Class Act NG 4.8 L/a + 2.5% v/v

13 Phostrol + Penncozeb 3.3 L/a + 2 lb/a

14 Phostrol + Bravo Weather

Stick 3.3 L/a + 1.5 pt/a

LSD at P=0.05

21



Treatment Rate Crop injury Biomass

------------------ % ------------------

1 Non-treated 0 100

2 Phostrol 2.4 L/a 21 88


4 Ingery MSO 6 fl oz/a 5 100

5 K-Tone 0.5% v/v 9 95

6 Phostrol + Inergy MSO 4.8 L/a + 6 fl oz/a 31 88

7 Phostrol + K-Tone 4.8 L/a + 0.5% v/v 24 90


LeciTech 4.8 L/a + 0.5% v/v 40 79

9 Phostrol + Silkin 2.4 L/a + 0.25% v/v 11 96


11 Phostrol + Class Act NG 2.4 L/a + 2.5% v/v 15 96


13 Phostrol + Penncozeb 3.3 L/a + 2 lb/a 18 95


Stick 3.3 L/a + 1.5 pt/a 13 94

LSD at P=0.05 10 7

22




------------------ % ------------------

1 Non-treated 0 100




5 K-Tone 0.5% v/v 9 95




LeciTech 4.8 L/a + 0.5% v/v 40 79







Stick 3.3 L/a + 1.5 pt/a 13 94

LSD at P=0.05 10 7

23




------------------ % ------------------

1 Non-treated 0 100




5 K-Tone 0.5% v/v 9 95




LeciTech 4.8 L/a + 0.5% v/v 40 79







Stick 3.3 L/a + 1.5 pt/a 13 94

LSD at P=0.05 10 7

Storage Tuber Testing

• Tubers were taken from

storage in January and

February 2015.

• Tested for phosphoric

acid in tubers.

• Challenge inculcated for

pink rot.

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Phosphoric Applied x Tuber Phosphite

26

Y = 11.8 + 0.34x

R2 = 0.24

Phosphoric acid x Pink rot

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Y = 5.1 – 0.11x

R2 = 0.12

Conclusions: Injury

• Apply earlier

• Use higher water carrier volumes

• Use lower rates (2.4-3.3 L/a)

• Silicone surfactants may help (don’t apply

foliar fungicide for 2-3 days after using

silicone surfactant)

Conclusions: Efficacy

• Air and air + chemigation had more phos acid in tubers tested.

• Chemigation alone had less phos acid in tubers tested.

• Tuber phosphite level of 30 ppm had < 2% pink rot incidence. But pink rot challenge was likely too late.

– Other research suggests 100 ppm is needed for Phythophtora spp. control.

More Studies in 2015

• Commercial Russet Burbank field (2015)

• RCBD with 4 replicates

• Treatments: Dose

– Test if earlier treatments will cause less burn and can

more easily be applied with ground sprayer

• Application started at tuber initiation and weekly

afterward

• Estimated biomass.

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Treatments

31

Treatment No. Rate (L/a) Treatment Date

1 Untreated Check 0

2 Phostrol 2.4 L/a 2.4 18-Jun






8 Phostrol 3.3 L/a x 3 3.3 9-Jul

3.3 16-Jul

3.3 23-Jul


2.4 16-Jul

2.4 23-Jul

2.4 30-Jul


4.7 23-Jul

11 Phostrol 4.7 L/a x 2 4.7 18-Jun

4.7 25-Jun


4.7 25-Jun

4.7 9-Jul

Emergence: 28 May

Row closure: 28 June

Estimated Biomass (4 DAT)

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Non-treated

33

14.2 L/a Phosphorous acid

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Graded Yield

Marketable Yield

Pink Rot Challenge

Pink Rot and Yield

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• Treatment 10:

- 9 & 23 July

• Treatment 11

- 18 & 25 June

• All Fs had a

treatment on

July 9th and/or

after

Treatments

39

Treatment No. Rate (L/a) Treatment Date

1 Untreated Check 0








3.3 16-Jul

3.3 23-Jul


2.4 16-Jul

2.4 23-Jul

2.4 30-Jul


4.7 23-Jul


4.7 25-Jun


4.7 25-Jun

4.7 9-Jul

Summary

• 3+ applications of phosphoric acid after

were best for pink rot control.

• Timing is important – after July 9th in this

study there was better pink rot control.

• Surfactant and silicone adjuvants can

help reduce injury when phosphoric acid

rates were low (<2.4 L/a).

40

What Does All This Work Mean?

• Multiple applications of low amounts

(<2.4-3.3 L/a) of phosphoric acid at the

right time with a surfactant/silicone will

provide the least injury and best

protection from pink rot.

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Acknowledgements

• Nufarm Americas Inc.

• JR Simplot Company

• RD Offutt Company

• MN Area II Research and Promotion

counsel

42

Questions /

Comments? z.umn.edu/spud

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