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Spencer S. Walse*J. Steve TebbetsDavid Obenland

David HallJoe Morse (UCR)

Beth Grafton Cardwell (UCR)Michael Rogers (UF)Beth Mitcham (UCD)Dan Kuzmich (ARS)

Breaking insect-related citrus trade barriers using postharvest treatments

2014-2015 CA Citrus Update - Walse

2) Systems-based (reduce need /requirements of #1)- mathematics of pre- & post- harvest factors- soaking (low WM organics) for FRB- ACP to AUS, brown rot w/ Adaskaveg

3) Regulatory - PH3 EPA off-gassing, OPP re-registration- EF report to organic board

1) Stand-alone - PH3 (Brevipalpus mites, red scale, Medfly)

- MB (ACP in Miami last week of April)- cold treatment, fogging degreening rooms (FRB)

- soaks/floods/dips

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Stand-alone fumigation: lab-scalephosphine , methyl bromide, ethyl formate

CRS

OFF/MF

BT

FRB mites

ACP

feasible standalone control option(s)

benefit from system approach

Asian citrus psyllid fumigation with MB~ 70 mg h/L will control adult ACP

( 3 lbs, 50F, 2 h)

PH3 fumigations ongoing at CRF - UC Davis

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Brevapalpus chilensis with MB

> 2-fold more difficult than ACP

~ 152 mg h/L will control adult ACP at 40F, 2.5 h

Relative sorption of fumigants into “naked” fresh produceexternal versus internal feeders

OFF

orange (0.51)

mites

very important for short treatments (MB)

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Brevipalpus chilensis with PH3 @ 1.3 ± 0.5 °C

B. species trade barrier to NZ ??

B. californicus & B. lewisi- MB studies ongoing in Parlier/Kearney (G.-Cardwell)- PH3 studies ongoing in Parlier/Kearney (G.-Cardwell)- EF studies ongoing at CRF – UC Davis (Mitcham)

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Standalone FRB treatments

2) Cold-treatment - “classic” preshipment” 22d at -0.5ºC (-5C for 5 d)- 34% mortality

3) IGR soaks w/ & w/out adjuvants- 200 ppm Imazalil “back ground” solution- 1:1 v/v spray-aid or 4.5% Prospect at 40C 15 – 30s- Applaud 70DF, Esteem .86 EC, Micromite 80wgs- 50% control w/ spray-aid & Micromite

1) Fogging- Acetic acid 1% - Fruit growers & Smilanick (USDA-ARS)- 19% mortality

4) Lime sulfur soaks at 40C- 44% control at 5% 30s exposures

Standalone FRB treatments

5) Organic acid soaks w/ & w/out adjuvants- acetic acid, formic acid, ethyl formate, isopropyl formate,- ethanol, methanol, methyl formate

- acetic acid 5 to10% (or more) , 40C, time, dry, “rinse”- No adjuvant

- > 76% mortality @ 90 s- 92% mortality @240s

- 1:1 v/v spray-aid or 4.5% Prospect at 40C- >97% mortality @ 90s

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Acetic acid soak – commercial

Bin drench (“room temp” fruit)

40C in 1:1 spray aid or 4.5% prospectfood-grade acetic acid (~6% vinegar)

“dry” bins in degreening room “overnight”

Bin dump onto line to rinse and pack per usualcommercial tests to start ASAP

FDA POLICY (http://www.fda.gov/ICECI/ComplianceManuals/CompliancePolicyGuidanceManual/ucm074577.htm):Acetic acid is generally recognized as safe for use in foods if it is of "food-grade" and is used in accord with good manufacturing processes.

FIFRA 25b exempt pesticides: malic acid, citric acid

Opportunity to

impact postharvest treatments

start finish

PRODUCTION POSTHARVESTPREPLANT

“SYSTEMS-BASED”

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FRBOFF/MF

postharvest control

production efforts

“systems” Probit 9 efficacy

General “systems” concept

CRS ACP

>>>>>>>>>>>>>>>>>>>>>>>

Systems-based:Cumulative evaluation of processes

General rule for the multiplication of independent probabilities(Finney, 1948; Rosenthal, 1978)

Sample size estimation(Couey & Chew, ARS & UF, 1986)

))(1))((1))((1(1)( 2121 EnPEPEPEnEEP

)(

) and (

a

baab

EP

EEP ) |EP(E (Eq. 2)

New rule for the multiplication of conditional probabilities

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• Dunking

• Soak tank

• Wall-o-water/Flooding

• Spraying

• Washing over brushes

– Brushes alone

• Washing over rollers

– Rollers alone

• Forced-hot air dryer (confirmatory

Evaluation of events/processes

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Systems evaluation: where we sit now

Exceeding “Probit 9” benchmark without postharvest fumigation

Systems approach for FRB

FRB

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FRB – egg physiology

Evaluation of events/processes

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Systems evaluation: where we sit now

To exceed “Probit 9” benchmark we need to string events

Trade Barriers (we break’em)

Politics/regulatory

$economics

science

X

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Phosphine Chronolgy:

commercial test planned in CA

CO2

Fumigation

AlP

Tablets

CO2 + PH3

PH3 Generator

Pure phosphine diluted in

air

Mg3P2

Tablets

Egypt 1934

1979

1994

2002

First AlP fumigations

1953

Fosfoquim S.A.

SYSTEMS-BASED

finalmitigation

step

Pure phosphine diluted in

supra O2 air

“Horn” phosphine – Fosfoqium S.A.Other factors for Korea: Precedence

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PH3 Applications: MB chambers, CA rooms

waxed

control fumigated

42 F, 48 h , 1500 ppm

field runcontrol fumigated

Fruit Quality w/ Phosphine

David Obenland, USDA-ARS

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Fumigants “off gas” (i.e., depurate) uniformly from boxed fruit over the course of cold storage with loss that follows first-order kinetic approximations given the applied doses and corresponding treatment temperature utilized in this study.

Other factors for Korea:Worker Safety – Inhalation Exposure

“Organic” (i.e., gaseous) fumigant residues in fumigated fruit decreased uniformlyover the course of cold-storage at 37 F and 34 F for oranges and grapes,respectively. Methyl bromide requires time-scales of days and phosphine requirestimescales of hours to reach USEPA food tolerences for both methyl bromide andphosphine residues in fruit (dashed red lines).

Other factors for Korea:Residues – Ingestion Exposure

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THANK YOU