Postharvest aspects in citrus fruit production:Postharvest aspects in citrus fruit production:new insights on future treatments

Samir Droby

Department of Postharvest Science, ARO, The Volcani Centerp

Competition places multiple demands on p p pcitrus fruit suppliers

Quantity

Quality: Specific On time 

Cost

Shi

• Taste (Brix/acid)• % Juice• Peel disorders

requirements:• Packaging• Pallets• Size

delivery

Shippers• Peel disorders• Firmness• Shelf life• Decay

Size• Tailor made• Quarantine

• Consistency

FlexibilitySafety: microbial and pesticide

Competition places multiple demands on p p pcitrus fruit suppliers

Quantity

Quality: Specific On time 

Cost

Shi

• Taste (Brix/acid)• % Juice• Peel disorders

requirements:• Packaging• Pallets• Size

delivery

Shippers• Peel disorders• Firmness• Shelf life• Decay

Size• Tailor made• Quarantine

• Consistency

Flexibility Pesticide residues

Most frequent complains in the marketcolorRind

browningRind breakdown

QCScales

DecayScaring

Oleo Mechanical Shapesize

Zero tolerance for decay in the market

Costly repacking at destination

Factors affecting development of postharvest decay of citrus fruit

Storage conditions Temp. & RH

Postharvest   handling

Mechanical & physiological damage

Fruit quality / physiological status Pre‐harvest history

Type of package

Drencher Postharvest treatment f it f it i

Postharvest treatment f it f it i of citrus fruit in

packhouseof citrus fruit in

packhouse

Pressure Washer detergent

Water rinse Water rinse

WaxSpray

Sorting

Soak tank/

Dryer

S tiDryer

Spray over rollers

Sorting& packing

Dryer

“Silver bullet approach”: f i id th l t t tfungicides as the only treatment

lmazalil TBZMRL 5 ppm MRL 5 ppmlmazalil TBZMRL 5 ppm MRL 5 ppm

1-]2,)2,4- dichlorophenyl)‐2‐(2‐ -)1,3(-2 thiazol‐4‐yl)‐1H‐

propenyloxy)ethyl]‐1H‐imidazole benzoimidazole

Guazatine (Panoctine) OPPMRL 5 ppm MRL 10 ppm

N N''' (i i di 8 1 t di l)N,N'''‐(iminodi‐8,1‐octanediyl)

Ortho‐phenylphenol 

Timelines for fungicide introductions and first reports of resistance development to Penicillium reports of resistance development to Penicillium

digitatum on citrus fruit

SOPP &OPP 36 59 Harding 195923 yr.

Harding, 1962

SOPP &OPP

Biphenyl

TBZ

36 59

44 62

62 70 Dave/Petrie, 1970

Harding, 1959

22 yr.

8 yr.TBZ

Benomyl

Imazalil

70

62 73

80 87 Eckert 1987

Laville, 197311 yr.

7 yr.Imazalil

Fludioxonil

Pyrimethanil

80

04

04 ?

c e t 98

Azoxystrobin

36 46 56 66 76 86 96 06

Year Introduced

04?

Year Introduced

Figure derived from: Kaplan, Dave and Petrie, Proc. Int. Soc. Citriculture. 1981: 788-791

Fungicide application in the packhouse

Drencher Spray

Wax

Dip tank On line Drencher

Mold infection and residues in fruit for different Imazalil concentrations in waxdifferent Imazalil concentrations in wax

F it di d i 500 l ti Ii lil f 30 dFruit dipped in a 500 ppm solution Iimazalil for 30 seconds can have a residue of between 0.75‐1.2ppm

Residue analysis of fungicides through out the packing season

Mg/kg

p g

Consolidation of forces to reduce pesticide residues – current situation

• Food safety has become competitive among                                                                   

pesticide residues – current situation

supermarket chains/supplyers

•Each supermarket chain now have there own MRLs

I d b di d NGO d di

•• ComplexComplex•• Not standardizedNot standardized

•Increased pressure by media and NGOs demanding produce free of chemical residues

•Pathogen resistance to fungicides

–– CodexCodex–– European UnionEuropean Union

I di id lI di id l•Key Fungicides have been withdrawn from the market

–– Individual Individual countriescountries

•• “Organic”“Organic”OrganicOrganic

R t i t f f i id Recent requirements for fungicide residues in citrus fruit: Russia

S. No. Active ingredients

Codex EUH Russiag

1 2-4 D 1 mg/kg 1 mg/kg 02 Imazalil 5 mg/kg 5 mg/kg 0.1 mg/kg3 Thiabendazole

(TBZ)10 mg/kg 5 mg/kg 1 mg/kg

What we can do to face this situation?

Understanding the basics: Disease is a process Disease is a process ………………

Spores Infection Germination Decay develop.Contamination

48 h

Adopting “multi hurdle/system Adopting multi-hurdle/system approach”

The hurdle concept:Combine several factors into hurdle effects thatpathogens should not be able to overcomepathogens should not be able to overcome

Combination and complementary treatments

100% 50% 10% 2% 0.1%Initial incidence

50% effective

80% effective

80% effective

80% effective

Minimizing postharvest losses of Minimizing postharvest losses of citrus fruit

Prober use of sanitizers and

fungicides

Avoiding wounding

fungicides

Orchard management &

it tiPathological

P kh h i

sanitation

Overcoming long delays

Packhouse hygiene and sanitationMaintaining cold

chain

long delays at the shed

Level 1: the Orchard: • Preventing injury during harvest and transport• Orchard sanitation (reducing inoculum)• Optimal harvest timing • Optimal harvest timing • Use sanitized harvest boxes/bins (reducing inoculum)

Level 2: arrival in the packhouse:• Transport and treat the fruit within 24 hours after harvest• Transport and treat the fruit within 24 hours after harvest

• Keep the fruit in shade

• Drench with fungicides/sanitizers Drench with fungicides/sanitizers

Level 3: equipment and packhouse sanitation:

• Packing line, floor should be cleaned on daily basis• Use of disinfectants, detergents• Monitor fungal populations in the air and on the packlineg p p p

Before disinfection After disinfection

Level 3: equipment and packhouse sanitation:

• Keep dirty area clean during working hours• Separate dirty area from the rest of the packing line

Exhaust fan

Level 4: Cooling, cleaning and sanitizing

cold rooms, containers and ship compartmentsm , p mp m

Level 5: Fungicide application

Spray water soak tank+ fungicidefungicide

heated water

C ti di ti fSoak tankDrenching Application in

wax

Curative: eradication of established infections &

protection

What is new in chemical control?What is new in chemical control?

Reduced risk fungicides for control of

Phenylpyrrole Strobilurin Anilinpyrimidine

Reduced risk fungicides for control of postharvest decay of citrus fruit

Scholar, Graduate (Fludioxonil)

Abound (Azoxystrobin)

Penbotec (Pyrimethanil)

y py py

Inhibition of signal Inhibition of amino Inhibition of gtransduction (Protein

kinase) acids and protein

synthesismitochondrial

respiration

Control of postharvest decay of citrus fruit by Scholarcitrus fruit by Scholar

4

5Valencia - Paking house exp

1

2

3D

ecay

(%) 4 Weeks in storage 5ºC+ 1 week shelf

0Water (HW) Scholar 1000ppm in

WaxScholar 500ppm in HW +1000 ppm in

Wax

Imazalil 500 ppm in HW+1000ppm in

Wax

3

4

(%)

3 Weeks at 5ºC + 13 days Shelf

Murcot - Paking house Exp

0

1

2

Dec

ay

Natural decay

Water (HW) Scholar 1000ppm in Wax

Scholar 500ppm in HW +1000 ppm in

Wax

Imazalil 500 ppm in HW+1000ppm in

Wax

y

A+

Fludioxonil AzoxystrobinFludioxonil

&

Azoxystrobin

4-(2,2-difluoro-1,3-b di l 4 l) 1H

&Methyl (E)-2-[2-[6-(2-

cyanophenoxy)pyrimidin-4-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile

yl]oxyphenyl]-3-methoxy-prop-2-enoate

Registration expected 2010

P i th il l l lPyrimethanil lmazalil

4,6-dimethyl-N-phenyl-2-pyrimidinamine

1]2)2 4 ) (

&py

1-]2,)2,4- dichlorophenyl)‐2‐(2‐propenyloxy)ethyl]‐1H‐imidazole

Control of postharvest decay of citrus f it b Phil b t

6010 d t 20 C

Valencia

fruit by Philabuster

20

40

10 d at 20 C 17 d at 5 C

Dec

ay (%

)

0Wax Only Philabuster 500

ppm in HW + waxPhilabuster 2000

ppm in waxImazalil 500 ppm

in HW + 1000 ppm in wax

202530

13 d at 10 C 4 d at 20 C

(%)

Grapefruit

05

1015

Dec

ay

Commecial

Fruit was wounded 24 hours before

Wax Only Philabuster 500 ppm in HW + wax

Philabuster 2000 ppm in wax

Imazalil 500 ppm in HW + 1000 ppm

in wax

Packhouse trial 2008

treatment

Pre-harvest application of fungicides to reduce postharvest decay

TopsinTopsin and and BenlateBenlate = same active ingredient= same active ingredient

to reduce postharvest decay

thiophanate-methyl benomyl

carbendazimTopsinTopsin BenlateBenlate

Effects of pre-harvest applications of Topsin on postharvest decay

70

80

90

100g

or s

tora

ge

Topsin

Control Kern Co. Lindcove1 Lindcove2

40

50

60

70

ter d

egre

enin

g

10

20

30

40

en m

old

% a

ft

0Gre

None 1,000 10,000 100,000 1,000,000

Inoculum density

CaliforniaJ. Smilanick

Reducing chemical residues: Control Alternatives

Soft and non-residual chemicals

Possible alternatives:• OPP

Heat treatments

• “Curing”

HCombinations of two or• OPP• Sodium bicarbonate• Quaternary ammonium Chl i

• Hot water

• Heated fungicide solutions

Combinations of two or more alternatives

• Chlorine• Ozone• Electrolyzed water

solutions

• Hot water dip or brush

Pre-harvest practices

Growth regulators (GA 2 4 D)

Biocontrol

Microbial biocontrol agents Growth regulators (GA, 2,4‐D)Microbial biocontrol agents

Integrated Control of Postharvest Decay of Grapefruit

8

10

12%)

After 4 weeks at 11°C + 2 weeks at 20°Ca

Decay of Grapefruit

2

4

6

8

Decay (%

bcb

cbc

0

8

10

12After 4 weeks at 20°Ca

2

4

6

8

Decay (%

)

b bbb

0b

“Natural infection”

Control of decay in cold stored Oranges ( T )

Decay (%)

(cv Tarocco)100 %

100

Decay (%)

Non Treated Control

60

80Shemer

Imazalyl+wax

20

40

7 14 21 460

Italy, (Treatments included a hot carbonate prewash)

Storage at 10 C (days)

Thank youThank you