Copper-free production of organic apples:

three years experience in The NetherlandsMarc Trapman

Bio Fruit Advies, Netherlands

Problems with Copper:

1. Accumulation in the orchard soil:– Cu input at reduced rate: 2000-3000 gr. Cu/ha year– Leaving the system: < 200 gr. Cu/ha year

2. European registration as fungicide3. Copper residues on fruits

Copper as fungicide

• Cheap• Persistent• Highly effective• No resistance• Brought spectrum fungicide

• Research : no alternative

Copper replacement =

Not another product but another strategy

System approach:1. Sanitation2. Low susceptible apple varieties3. Careful planning and decision making4. Beware of other diseases5. Alternative fungicides

Alternative materials for scab controlMaterial Kg/ha Effectivenes

sRemarks

Copper 50% 0,2-0,5 Protective ++++

- Post bloom applications cause fruit skin russetingSulfur 80% 5-8 Protective ++ - Unreliable after 5 mm of rain- Risk for sun burn of fruits- Can not be used on all apple and pear varieties

Lime sulfur 12-20 Protective ++Curative ++++

- Instable, degrading to sulfur in ± 24 wet-hours- Post bloom applications can cause fruit skin russeting on other varieties than Golden.- Intense use can damage leafs.- Aggressive, corrosive, pH > 12- Not to be tank mixed with other materials.

Potassium bicarbonate

5-10 Protective +Curative +++

- Very water-soluble, therefore unreliable after less than 5 mm of rain.- Intense use can damage leafs.- pH 8.5- Not to be tank-mixed with other materials then sulfur.

Preventive treatmentCopperSulfur

Potassium bicarbonate

Bio Fruit Advies 10

Mills 1944Mills 1944

Bio Fruit Advies 11

Mills 1944Mills 1944

“Stop spray”Sulfur,

Lime sulfur,Potassium Bicarbonate

Pseudo-CurativeLime sulfur ~300 HDBicarbonate ~300 HD

2007-2008-2009 Working group:“Copper free production of Elstar”

• Discussion and agreement on strategy• All growers applied the strategy on one block of Elstar• On farm stations and RIM infection calculations on

Internet• Regular checks and meetings for feed-back• Strategies developed trough the years

Copper-free strategie 2009

Copper-free Standard Organic

Bud burst-Flowering

Protective: sulfurStop-Spray: sulfur+ bicarbonatePost infection: lime sulfur on main infections

Protective: copperPost infection: lime sulfur on main infections

Flowering-June

Protective: sulfur (+boron)Stop-Spray: sulfur+ bicarbonate

Protective: sulfur (+boron)Stop-Spray: sulfur+ bicarbonate

June-July

Stop-Spray: sulfur+ bicarbonateLime sulfur (In case of scab problems)

Stop-Spray: sulfur+ bicarbonateCopper + sulfur (In case of scab problems)

August-Harvest

Protective: sulfur + Mycosin Protective: copper + sulfur

One mistake in spring and the season is losst !

Percentage fruits with scab lesions at harvest2007 2008 2009

Orchard Cu-free Standard Cu-free Standard Cu-free Standard

Korstanje 0,0 3,4 4,3 1,1

Albers 2,2* 3,0 6,4* 3,0

Flikweert 1,6* 0,0 1,0 1,1 25,21,0

Poley 3,6 0,8 11,2* 1,9 18,3 4,3

Konijn 0,6 0,0 0,2 0,3 0,1 0,3

Peters 0,5 0,1

Van Noord 6,0 5,9

Levels 9,2 13,6

Damen 15,2* 2,8

Stoop 18,5* 11,3

Stoker 39,3* 21,1

Average 1,6 1,4 4,6 1,5 13,3 7,4

Percentage fruits with scab lesions at harvest2007 2008 2009

Orchard Cu-free Standard Cu-free Standard Cu-free Standard

Korstanje 0,0 3,4 4,3 1,1

Albers 2,2* 3,0 6,4* 3,0

Flikweert 1,6* 0,0 1,0 1,1 25,21,0

Poley 3,6 0,8 11,2* 1,9 18,3 4,3

Konijn 0,6 0,0 0,2 0,3 0,1 0,3

Peters 0,5 0,1

V Noord 6,0 5,9

Levels 9,2 13,6

Damen 15,2* 2,8

Stoop 18,5* 11,3

Stoker 39,3* 21,1

Average 1,6 1,4 4,6 1,5 13,3 7,4

4xsame

4xsame

Percentage fruits with scab lesions at harvest2007 2008 2009

Orchard Cu-free Standard Cu-free Standard Cu-free Standard

Korstanje 0,0 3,4 4,3 1,1

Albers 2,2* 3,0 6,4* 3,0

Flikweert 1,6* 0,0 1,0 1,1 25,21,0

Poley 3,6 0,8 11,2* 1,9 18,3 4,3

Konijn 0,6 0,0 0,2 0,3 0,1 0,3

Peters 0,5 0,1

V Noord 6,0 5,9

Levels 9,2 13,6

Damen 15,2* 2,8

Stoop 18,5* 11,3

Stoker 39,3* 21,1

Average 1,6 1,4 4,6 1,5 13,3 7,4

worseworse

worseworse

Percentage fruits with scab lesions at harvest2007 2008 2009

Orchard Cu-free Standard Cu-free Standard Cu-free StandardKorstanje 0,0 3,4 4,3 1,1Albers 2,2* 3,0 6,4* 3,0Flikweert 1,6* 0,0 1,0 1,1 25,2

1,0Poley 3,6 0,8 11,2* 1,9 18,3 4,3Konijn 0,6 0,0 0,2 0,3 0,1 0,3Peters 0,5 0,1V Noord 6,0 5,9Levels 9,2 13,6Damen 15,2* 2,8Stoop 18,5* 11,3Stoker 39,3* 21,1Average 1,6 1,4 4,6 1,5 13,3 7,4

Both badBoth bad

Percentage fruits with scab lesions at harvest2007 2008 2009

Orchard Cu-free Standard Cu-free Standard Cu-free Standard

Korstanje 0,0 3,4 4,3 1,1

Albers 2,2* 3,0 6,4* 3,0

Flikweert 1,6* 0,0 1,0 1,1 25,21,0

Poley 3,6 0,8 11,2* 1,9 18,3 4,3

Konijn 0,6 0,0 0,2 0,3 0,1 0,3

Peters 0,5 0,1

V Noord 6,0 5,9

Levels 9,2 13,6

Damen 15,2* 2,8

Stoop 18,5* 11,3

Stoker 39,3* 21,1

Average 1,6 1,4 4,6 1,5 13,3 7,4

Conclusions

• Skilled and highly motivated growers: still only 50% successful• Pre-infection copper strategy more robust then careful

scheduled sulphur+ bicarbonate treatments

• No effective materials for organic to be expected• Cu-free = optimization of use of existing materials and

knowledge• Effective Cu-free scab control requires:

– Well trained fruit growers– Well trained advisers– High quality spraying equipment– Highly accurate warning systems– Continuous awareness of the situation