CONSIDERATIONS WHEN REPLANTING WALNUTSREPLANTING WALNUTS

USING FUMIGANTS

Carolyn DeBuse Farm Advisor Solano & Yolo Counties

REASONS TO FUMIGATEREASONS TO FUMIGATE

Replanting Walnut to WalnutReplanting Walnut to WalnutVery old orchard with established nematode problemsproblemsTime restrictions –reduce fallow timeCan not change rootstock

ECONOMIC CHOICEECONOMIC CHOICE

Bruce Lampinen, UC Extension Specialist

After nine years at a seasonal average midday stem water potential of:

Bruce Lampinen, UC Extension Specialist

water potential of:

-5 bars -7 bars -9 barsYield (tons/ac) 4 3.2 2.4Cum. yield 18.0 14.0 10.8Cum. yield 18.0 14.0 10.8Cum. dollars $36,000 $28,000 $21,600Per acre loss -$8,000 -$14,400

80% 64% 48%

ECONOMIC CHOICESECONOMIC CHOICES

~45% midday light interceptionPotential for 2.2 tons/acre

~30% midday light interceptionPotential for 1.5 ton/acre

Bruce Lampinen, UC Extension Specialist

TESTING FOR NEMATODESTESTING FOR NEMATODES

Take multiple soil samples from the old orchard p pat depths of 18-36 inches deep.

Include various soil typesInclude live roots in sampleSample when soil is moistCombine soil samples that are similar in depth and soil type

Send to Lab for nematode count of each species

UNDERSTANDING YOUR NEMATODE SAMPLEUNDERSTANDING YOUR NEMATODE SAMPLE

Nematodes SpeciespLesion nematode- Pratylenchus vulnus-

A count of one is too high

Ring nematode-Mesocriconema xenoplax-Also bad for walnuts

Root-knot nematode-Meliodogyne spp.-Can be problematic but not severe

Decision 85 % of aln t orchards ha e too Decision: 85 % of walnut orchards have too high of a nematode population and fumigation is neededis needed

SOIL TYPE CONSIDERATIONS AND FUMIGATIONSOIL TYPE CONSIDERATIONS AND FUMIGATION

In light sandy loam soil the In light sandy loam soil the fumigation moves through the soil freely soil freely In heavy silt y clay soil fumigation moves slower and fumigation moves slower and not as farG t i l Gas movement is also dependant on dryness of soil

SOIL TYPE CONSIDERATIONS AND FUMIGATION SOIL TYPE CONSIDERATIONS AND FUMIGATION

Fumigants move 10,000 to 30,000 times Fumigants move 10,000 to 30,000 times faster in “soil-air” than “soil-water”Methyl bromide works in heavy soilMethyl bromide works in heavy soil

Colder soil temps (42-80°F) & works well in high moisture soils moisture soils

1,3 Dichloropropene (Telone II )does not!N d 55°F il t & l k i il t Need > 55°F soil temps & locks up in soil-water Want soil moisture at 12-18%

SOIL MOISTURE REQUIRED FOR DIFFERENT TREATMENTS AND SOIL TYPES

FUMIGANT NAMEAPPLICATION AMOUNT

SOIL TYPESOIL

MOISTUREMethyl bromide 225-350 lb/ac injected at

TREATMENTS AND SOIL TYPES

Methyl bromide (restricted use only)

225-350 lb/ac injected at 10 in.

any 12-18%

1,3 Dichloropropene(Telone II)

33.7 gpasandy-sandy loam

TIMELINE FOR PREP AND FUMIGATIONTIMELINE FOR PREP AND FUMIGATION

Year oneOctober –November 15th : kill roots60 days; remove trees

Year twoMarch-May: plant or leave fallowAugust: Soil ripping and cultivationSeptember-November: Fumigate

Plant: January -April Total time= 18-20 months

TREE REMOVALTREE REMOVAL

By November 15thBy November 15Cut treesPaint stumps with Paint stumps with

50ml Garlon plus 50ml MorAct.W i 60 DWait 60 DaysNote: Prunus species you can use glyphosate (Roundup) plus MorAct

TREE REMOVALTREE REMOVAL

60 Days after trees ywere killed remove stumps and rip

Within 5 months 99% of nematodes inside roots have ground

been killedBy next summer the roots left in the soil will disintegratedisintegrateIt takes 2 ½ years of fallow to lower nematode populations to the same level as 1 year with Garlonp p y

SOIL PREPARATIONSSOIL PREPARATIONS

1. Starve the remaining soil borne gnematodesD i t th il 2. Drying out the soil

3 Texture of soil at fumigation 3. Texture of soil at fumigation needs to be loose 5 feet deep

SOIL PREPARATIONSSOIL PREPARATIONS

Starve the remaining soil borne nematodesFallow-

Reduces nematodes 50%

Plant alternative cropSudan grass- (reduce nematodes 85%)SafflowerWheatA th th th bAny other crop other than beans

SUDAN GRASS

Peach RD, Parlier: effects of fumigation treatments x sudan rotation

Fumigation treatmentFumigant /treated A

Fumigant/ orchard A

Sudan grass rotation

Trunk dia. increase by 30 Aug 2008Fumigation treatment

(Oct 2007)/treated A

(lbs)orchard A

(lbs)rotation

(Jul‐Sep 2007)by 30 Aug 2008 

(mm)

Control 0 ‐‐no 7.9

yes 14.1

MB, by conventional shanks to  8’‐wide row strips

400 168no *22.6*yes *20.4*

Telone C35, by conventional shanks to 8’‐wide row strips

540 227no *28.3*yes *31 9*shanks to 8 wide row strips yes 31.9

Telone C35, by GPS‐controlled shanks to 5x 6’ tree spots

540 81no *21.4*yes *24.2*

Inline, by single drip emitters540 43

no *20.8*to 4’‐dia. tree spots

540 43yes *21.3*

CP, by GPS‐controlled shanks to 5x6’ tree spots

400 60no *24.2*

yes *26.5*

Mi i i ifi t diff ( di t 95% fid i t l ) 8 9Minimum significant difference (according to 95% confidence intervals): 8.9

Greg Browne; 2007

INTERIM CROP DIFFERENCESINTERIM CROP DIFFERENCESPeach RD, Parlier: effects of fumigation treatments x sudan rotation

Pre‐plant rotation Disease 

severity rating 

Trunk Diameter 30 Aug 2008 

Pre Fumigation treatment treatment 7 July 2008 (mm)

Control

No fallow 0.9 25.31 year fallow 0.7 28.8

ControlMustard 0.7 29.0

Wheat‐Sudan 0.5 29.5No fallow 0.4 34.9

Chloropicrin 400 lb/A1 year fallow 0.3 39.1Mustard 0.2 40.4

Wheat‐Sudan 0.2 40.7

Greg Browne; 2007

SOIL PREPARATIONSSOIL PREPARATIONS

Drying out the soil Heavy soils need to be at 12-18% by fumigation

Plant a crop to dry soilFallow and rip and disc down to 4-5 feetRepeat ripping and tilling through out summerTest soil moisture – Sample soil at different depths 1-5 feet; weigh sample, then dry, and weigh againweigh again

Goal is 12% to 5 feet deep > 12% will require more fumigant q g

SOIL PREPARATIONSSOIL PREPARATIONS

FUMIGATION TIMINGFUMIGATION TIMING

Before Nov 15thBefore Nov 15Soil Temperatures >55°F- Not a problem in California (at one foot depth)California (at one foot depth)Before 2 inches of rain fall

FUMIGATION CHOICESFUMIGATION CHOICES

For heavy walnut soilsFor heavy walnut soilsMethyl bromide is hard to find and too expensiveTelone II- 1 3 DichloropropeneTelone II- 1,3 DichloropropeneChloropicrin- not to be used alone but in tandemTelone C35 1 3 Dichloropropene plus ChloropicrinTelone C35- 1,3 Dichloropropene plus ChloropicrinMetam-sodium (Vapam) not a true fumigant but can be used at soil surface levels to sterilize the top can be used at soil surface levels to sterilize the top layers if tarp is not used (check w/ ag com)

Methyl Bromide AlternativesMethyl Bromide AlternativesTrialTrial Kings CountyKings CountyTrialTrial--Kings CountyKings County

Bob Beede, UC Kings Co. Farm Advisor

Dan Kluepfel, USDA-ARS Davis

Mike McKenry, Extension Specialist Riverside

Lani Yakabe, Graduate Research Assistant,

UCD Plant Pathology

Tony Garcia, Kings Co. Ag. Assist.

Gold Top Ranch Alternate Fumigation Trial (2008) Trunk Caliper Measurements in (MM) Thur. 12-18-08

24 8 25 3 25 3

30.0

20.0

24.8 25.3 24.6 25.3 24.023.9

20 0

25.0

in M

M.

0 lb

/ac

ated

t 2

0"

dcas

t &

d at

20"

cast

&

5 lb

/ac

anke

d at

28"

t and

m

ide

@

15.0

20.0

er M

eas.

ntro

l

adca

st @

400

/ac

strip

trea

& s

hank

ed a

t

gal/a

c br

oad

shan

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al/a

c br

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20"

Plus

175

cast

and

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ast

Met

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rees

10.0

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alip

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I @ 3

3.7

gal/

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125

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1 2 3 4 5 6 7Treatments Number 7 is the Buffer rows

Bob Beede, UCCE Kings County

35

RING NEMATODEAVERAGE POPULATION PER FIVE FOOT DEPTH

30

35Bob Beede, UCCE Kings County

25

250c

c

15

20

ATO

DES

/2

10NEM

A

0

5

control MeBr TELONE II-STRIP

TELONE II-BROAD

TELONE II +C-PI

TELONE +MeB

ring pre ring 21d ring 119d ring 410d ring 560d

350

LESION NEMATODEAVERAGE POPULATION PER FIVE FOOT DEPTH

300

350Bob Beede, UCCE Kings County

200

250

250c

c

150

200

ATO

DE/

2

100NEM

0

50

control MeBr TELONE II-STRIP

TELONE II-BROAD

TELONE II +C-PI

TELONE +MeB

lesion pre lesion 21d lesion 119d lesion 410d lesion 560d

APPLICATION CONSIDERATIONSAPPLICATION CONSIDERATIONS

Sealing Shank cut Sealing Shank cut immediatelyBuessing shank- has wings Buessing shank- has wings to seal the behind injectionsFollow shank with disc and

15-20 inches

Follow shank with disc and roller

24-30 inches

Tarp

APPLICATION CONSIDERATIONSAPPLICATION CONSIDERATIONS

At 12-15%332 lbs/A Telone at 18”plus 150 lb/A 332 lbs/A Telone at 18 plus 150 lb/A Chloropicrin at 26”

At >15-19%

15-20 inches

332 lbs/A Telone at 18”plus 250 lb/A Chloropicrin at 26”Consider 12’ strip application to tree row with double the Telone but equal to

24-30 inches

with double the Telone but equal to 332Lbs/A

Michael McKenry, 2002

APPLICATION CONSIDERATIONSAPPLICATION CONSIDERATIONS

Reality checkReality checkTelone II @ 18 inches ($)Telone C35 @ 18 inches ($$)Telone C35 @ 18 inches ($$)Methyl bromide ($$$) if available still the top choice

18 inches

available still the top choice even if cost is highBuessing Shank southern

Followed by roller to seal the soilBuessing Shank southern

California hires for 60-100 acres ($$$)

Soil Fumigant RegulatoryUpdateUpdate

Even more restrictions coming your way!

• Methyl Bromide phase-out under the Montreal Protocol/Clean Air Act (EPA - Office of Air)

g y y

– To prevent destruction of stratospheric ozone layer

• Telone Township Caps (CDPR)f– To protect bystanders/neighbors from chronic exposure

• VOC Soil Fumigant regulation in the SJV (CDPR/SJVAQCD/ARB/ EPA Office of Air))– To reduce ground level ozone formation

• Reregistration of Soil Fumigants (EPA -Office of Pesticide Programs)To protect bystanders/neighbors from acute and chronic exposures– To protect bystanders/neighbors from acute and chronic exposures

Gabriele Ludwig (Almond Board of California)

Soil Fumigant RegulatoryUpdateUpdate

• EPA reviewed the risks from all soil fumigants:

EPA’s Reregistration Eligibility Decision (RED)• EPA reviewed the risks from all soil fumigants:

– Methyl Bromide, Chloropicrin, Metam Sodium, Dazomet, Methyl Iodide• Telone reregistered in 1998 so not part of this RED.

• In 2010-11 new labels with new restrictions • Major requirements include:

– Major buffer zones for MeBr and PicC dit f t i ki d f t il t il l• Credits for certain kinds of tarps or soil types or soil seals

– Notification of neighbors in advance of fumigation OR - Extensive, costly monitoring outside of buffer– Need to break up fumigations into smaller blocks– Can’t overlap buffer zones

• Must have written OK for any buffer zone that extends onto neighboring public or private land.p p

– Fumigant Management Plan required

Gabriele Ludwig (Almond Board of California) c

Notification OR MonitoringRequirementRequirement

Notification depends on size of buffer:

If b ff i Th i hb ithiIf buffer zone is: Then neighbors withindistance from edge of buffer must be

notified:

< 100 ft within 50 ftIf 100300 ft within 300 ft

OR

Need to monitor space between bufferzone outer edge and neighbor everyhour during application and entire buffer zone period (5 days min).

If exceed certain limits must startfumigation evacuation plan.

Gabriele Ludwig (Almond Board of California) c

ROOTSTOCK CHOICESROOTSTOCK CHOICES

Paradox Clone: VX211Paradox Clone: VX211Preliminary findings that VX211 tolerates nematode feedingnematode feedingIf population too high tolerance disappears

California Black supports fewer nematodes California Black supports fewer nematodes than Paradox seedling , but less vigorousE gli h t l g l ti f English supports large populations of nematodes

GOLD TOP RANCH FUMIGATION ALTERNATIVE TRIAL (2008) CALIPER MEASUREMENTS IN MM

THUR. DEC. 12, 2008

30

35

2124

2725

30

M

15

20

AVG

. IN

M

5

10

A

0

PARADOX VLACH VX-211

Bob Beede, UCCE Kings County

Average Diameter (mm) Jan 2010

RESULTS FROM RESULTS FROM SOLANO COUNTY SOLANO COUNTY ROOTSTOCK TRIALROOTSTOCK TRIAL20

25

30

35 aab

dcc

ROOTSTOCK TRIAL ROOTSTOCK TRIAL PLANTED 2009 PLANTED 2009

5

10

15

20

0

Vlach 2 VX211 Vlach 1 Pdx. Seedling

Burbank RX1

Estimated Height (ft) Aug 2009

6

7

8

Estimated Height (ft) Aug 2009

ab b

c cd

2

3

4

5 dc cd

0

1

Vlach 2 Vlach 1 VX211 RX1 Pdx. Seedling Burbank

NUTRIENT ADDITIONSNUTRIENT ADDITIONSSoil micro and macro nutrients can be depleted

P i h d Previous orchard Fumigation can lower Phosphorous and Zinc

Some debate over adding nutrients to just planted walnuts

studies showed 1/6 lb ‘20-20-20’ plus 8.3 ml of ‘Super Micro’ with 2 gallons of water at planting

f fdoubled the size of trees in first yearspoon feed nitrogen through out season

Leaf sample in July

THANK YOU