Orchard Replanting: Mitigating the possible Impacts of Soilborne Problems.

David Doll

CAPCA Fall 2011

10-5-11

Replant Problems of Perennial Nuts

1.Current control strategies for mitigating soilborne pathogens and nematodes upon replanting almonds.

2. Background research into the etiology of replant problems of almonds.

3. Briefly touch on fumigate selection for replanting walnuts.

• Abiotic factors (physical, chemical conditions related to previous production)

• Aggressive pathogens, pests

(Phytophthora, Armillaria, Verticillium, Ten-Lined June Beetle) –localized, not managed completely by fumigation

• Plant-parasitic nematodes

(ring, lesion, root knot), approx. 35% of almond and fresh stone fruit acreage, 60% of cling peach acreage infested (McKenry)

• Replant disease (RD) Microbe-induced growth suppression; incidence nearly universal in Prunus after Prunus, but severity varies greatly

Healthy tree RD-affected tree

Symptoms of replant disease on almond

The Replant Problems

Abiotic Factors Learn from the old orchard! Aerial image through Google Earth, walking the field Determine areas of variability and address •Soil Modification – ripping, backhoeing, slip-plowing

•Irrigation system – High volume/low volume

•Rootstocks – Determine options for salinity, boron, alkalinity, high water table, etc.

Management of Aggressive Pathogens

• Can affect any soil type; consider history of old orchard

• Fumigation is not able to

completely eradicate, but reduce population

• Fumigants that include methyl bromide

• Provide conditions that favor a thorough fumigation

• Cultural Practices and Resistant

Rootstocks for Phytopthora and Armillaria– Marianna 2624, Ishtara, Krymsk-86

Plant Parasitic Nematodes

Ring Nematode -Bacterial Canker Complex

Rootknot Nematode –Galls

on roots

Lesion Nematode – root damage

Plant Parasitic Nematodes– Pre-plant Sampling

Interpreting Results:

Main Question: Are the there main nematodes there, or not?

If not, fumigation is not

needed for nematodes.

If so – how many are present?

Plant Parasitic Nematodes– Pre-plant Sampling

Nematode Low Population (<40/L)

Medium Population (40-150/L)

High Population (>150/L)

Rootstock Available?

Rootknot Cover Crop Row Strip Fumigate

Nemaguard, Offspring of Nemaguard (Most Hybrids)

Ring Row Strip Fumigate, Cover Crop

Row Strip Fumigate, Cover Crop

Broadcast Fumigate, Cover Crop

Tolerant Rootstocks – Lovell, Viking NO P/A Hybrids!

Lesion Cover Crop Row Strip Fumigate, Cover Crop

Broadcast Fumigate, Cover Crop

Any Vigorous Rootstock (P/A Hybrids)

Plant Parasitic Nematodes– Management

Replant Disease of Almond

Healthy RD-affected

Healthy (L) and replant disease-affected (R) almond trees, Madera County 2007

Replant Disease of Almond: Management

Fine texture soils do not tend to have as severe of replant disease problems

Fallow or cover crop for at least

one year Fumigate row strips with

chloropicrin containing fumigants

Switching rootstock parentage

may provide some control, but sacrifices other horticultural benefits

2006 - 3rd 2007 - 4th 2008-5th 2009-6th 2010 - 7th Total

Control 294 1812 2868 1996 2672 9642

MB 400 lb/a Br. (100%) 282 2262 3103 2551 2403 10601

MB 400 lb/a R. Strip (38%) 424 1894 3197 2323 2359 10197

Telone II 340 lb/a Br. (100%) 547 2199 3111 2879 3113 11849

Telone II 340 lb/a R. Strip (38%) 483 2026 3063 2130 2799 10501

TeloneC35 535 lb/a Br. (100%) 637 2385 3458 3080 2711 12271

TeloneC35 535 lb/a R. Strip (38%) 696 2133 3087 3031 2643 11590

IM:CP 400 lb/a Br. (100%) 682 2364 3246 3078 2690 12060

IM:CP 400 lb/a R. Strip (38%) 632 2241 3309 3317 2900 12399

CP 400 lb/a Br. (100%) 554 2191 2937 2860 2459 11001

CP 400 lb/a R. Strip (38%) 680 2301 3211 2984 2540 11716

Nonpareil Yield Responses, 2003 almond replant trial, Madera Co. (Fumigated Oct 2003, planted Jan 2004)

696 – 294 = 402lbs ($663 at $1.65/lb) 11590 – 9642 = 1948 lbs($3214 at $1.65/lb)

Replant Problems of Almonds: Fumigant Selection

Problem Fumigant Method

Nematode Parasitism

Telone II or Telone C35

Broadcast or Row Strip

Replant Disease Chloropicrin or Telone C35

Row Strip or Tree Site

Aggressive Pathogens

Chloropicrin/ Methyl Bromide

Broadcast

Replant Problems of Perennial Nuts

1.Current control strategies for mitigating soilborne pathogens and nematodes upon replanting.

2. Background Research into the etiology of replant problems

3. Briefly touch on fumigate selection for replanting walnuts.

USDA MBA: Almond Replant Trials Field trial locations & start dates:

Madera County, San Joaquin Valley:

• 2003, Agriland, almond after almond (sandy loam) (fr. CSREES)

• 2006, Paramount, almond after almond (sandy loam)

• 2007, Agriland, almond after almond (sandy loam)

• 2009, Poythress, almond after almond (loam)

Fresno County, San Joaquin Valley :

• 2007, USDA-ARS Parlier, peach after plum (sandy loam)

• 2007, USDA-ARS Parlier, almond after peach (sandy loam)

• 2008, Berberian, Reedley, peach after peach (sandy loam)

• 2008, KAC, Parlier, almond after peach (sandy loam)

• 2008, USDA-ARS, Parlier, peach after peach (sandy loam)

• 2010, USDA-ARS, Parlier, almond and peach rootstocks x Tel C35 fum

Colusa County, Sacramento Valley:

• 2007, almond after almond, Nickels Estate (loam)

Merced County, San Joaquin Valley :

• 2009, Frago, almond after almond (sand)

• 2010, Littlejohn, almond after almond (sand)

Management of Replant Disease on Almond

• “It is a root problem.”

• “Only occurs with Prunus following Prunus ”

• “It is not just a growth response from the fumigant.”

• “Low levels of Chloropicrin control the problem”

• “Cover cropping helps”

Replant Disease of Almond: Effect on the root system

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Root diameter (mm)

Control

Pre-plant chloropcirin

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Root diameter (mm)

Control

Pre-plant chloropcirin

Marianna 2624 rootstock Lovell peach rootstock

To

tal ro

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Root length densities at 0 to 2 ft depth; determined by root

excavation and digital imaging

Replant Disease of Almond: Fumigant Benefit

Nemaguard Seedlings planted in soils that have been previously cropped in

peaches or grapes for 15 years. Microplot trials.

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Peach Grape

Control

Methyl Bromide

Chloropicrin

Telone II

Telone II C35

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Rate of chloropicrin (kg/tree site)

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Growth and 1st year yield response of almond to pre-plant spot fumigation treatments with chloropicrin (0.25 to 2.0 lb / tree site), Butte County

Replant Disease of Almond: Fumigant Selection/Rate

Application of pre-plant cropping and fallow treatments. Microplot experiments.

Replant Disease of Almond: Cover Cropping

Responses of Nemaguard peach seedlings to short-term fallow, rotation treatments, microplots, Parlier

Top

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sh w

t. e

nd

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Averages from three 2-year experiments

Replant Disease of Almond: Cover Cropping

The affects of Piper-Sudan on replant disease of peach. Field Trials. Planting: O’Henry Peach on Nemaguard following 20 yr old Santa Rosa Plums on Marianna 2624

Replant Disease of Almond: Cover Cropping

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Control Sudan

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P=0.048

Replant Disease of Almond: Cover Cropping

Management of Plant Parasitic Nematodes

• “Use fumigants that contain Telone II”

• “Strip fumigation provides three to five years of nematode relief – broadcast may hold longer”

• Most Recent: Walnut replant trial hosted by Bob Beede in Kings County

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control MeBr TELONE II-

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

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RING NEMATODE

AVERAGE POPULATION PER FIVE FOOT DEPTH

Effect of Fumigant on Nematodes: Case Study from Replanting Walnuts

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control MeBr TELONE II-

STRIP

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C-PI

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MeB

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

LESION NEMATODE

AVERAGE POPULATION PER FIVE FOOT DEPTH

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MA

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/250

cc

Effect of Fumigant on Nematodes: Case Study from Replanting Walnuts

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control MeBr TELONE II-

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nonp pre nonp 21d nonp 119d nonp 410d nonp 560d

NONPARASITIC NEMATODES

AVERAGE POPULATION PER FIVE FOOT DEPTH

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Effect of Fumigant on Nematodes: Case Study from Replanting Walnuts

Replant Problems of Perennial Nuts

3. Briefly touch on fumigate selection for replanting walnuts.

Methyl Bromide Alternatives for Replanting Walnuts

Kings County

Bob Beede, UC Kings Co. Farm Advisor

Mike McKenry, Extension Specialist Riverside

Dan Kluepfel, USDA-ARS Davis

Tony Garcia, Kings Co. Ag. Assist.

2. Orchard removal fall: 2006

A. Trees pushed and chipped

B. Ground chiseled to 3 feet

C. Days spent collecting old roots

D. Field then disked, irrigated, and prepared for spring corn planting

Methyl Bromide Alternatives for Replanting Walnuts Kings County

Field Site Following Modification

Field Site Ready for Fumigation

1. Untreated Control (2.07 acres) 2. Methyl Bromide broadcast @ 400 lb/ac (2.07 acres) 3. Telone II @ 33.7 gal/ac strip treated (10’ swath) & shanked at

20” (2.07 acres) 4. Telone II @ 33.7 gal/ac broadcast & shanked at 20” (2.07 acres) 5. Telone II @33.7 gal/ac broadcast and shanked at 20” , Plus 175

lb/ac Chloropicrin broadcast and shanked at 28” (2.07 acres) 6. Telone II @ 33.7 gal/ac broadcast and shanked at 20”, Plus

Methyl Bromide @ 125 lb/ac at 28” depth (2.07 acres)

Kings County Methyl Bromide Alternatives Treatments Six Replications per Fumigant, 12 Trees per plot

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Effect of Fumigant Treatments on Growth of Pre-Grafted Walnuts

Gold Top Ranch Walnut Replant Trial (12-18-08)

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Effect of Fumigant Treatments on Growth of First Leaf Walnuts

Gold Top Ranch Walnut Replant Trial (11-10-09)

b b b

b b

a

FUMIGATED Two-year-old Tulare Scion

OCTOBER 27, 2010

NO FUMIGATION CONTROL

SAME TREE AGE

OCTOBER 27, 2010

Should I Consider Recommending a Grower to Fumigate?

• Yes – especially in lighter soils. Economically, it pencils out as a wise investment.

• Best treatment depends on pressure present.

• If Nematodes are there, products must contain Telone II.

• Low rates of chloropicrin have been shown to increase tree growth; may have application for heavier soils.