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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
ked
al/a
c br
oadc
20"
Plus
175
cast
and
sh
c br
oadc
ast
Met
hyl B
rom
h er T
rees
10.0
vg. C
alip
e
trea
ted
Con
rom
ide
broa
I @ 3
3.7
gal/
10' s
wat
h) &
ne II
@ 3
3.7
g
e II
@ 3
3.7
gsh
anke
d at
pi
crin
bro
ad
@ 3
3.7
gal/a
at 2
0" P
lus
Mat
28"
dep
th
Buf
f
0.0
5.0Av
Un
Met
hyl B
r
Telo
ne II (
Telo
n
Telo
ne
Chl
orop
Telo
ne II
@sh
anke
d a
125
lb/a
c
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