Evaluation of Organic Seed andEvaluation of Organic Seed and Drench Treatments for Damping‐off 

in Organic Pea Crops

Ana Vida Alcala1, Lindsey du Toit1, and Lyndon Porter2

1WSU Mount Vernon NWREC, and 2USDA‐ARS, ProsserWSU Mount Vernon NWREC, and  USDA ARS, Prosser

Background 

Poor crop standSeed quality 

S db thPoor crop stand Soilborne pathogens

Seedborne pathogens

p g

Pythium spp. 

Fusarium spp.

Rhizoctonia spp.

Background 2009 WA organic vegetable grower interviews 

f lSignificant losses to poor emergence. • replant entire fields • greater seeding rate than conventional crops g g p(weed control  and poor stands) 

Early planting = critical factor associated with poor stands.

Reasons for early planting :id d

y p g p

• avoid weeds• harvest and process before conventional crops • double cropping

Background2009 WA organic vegetable grower interviews 

Organic seed treatments are not widely used: inconsistency.

$Growers’ willing to pay ≥ $100/acre for a treatment that consistently results in 30% increase in stand.

Pea cultivars planted early in the season in WA for processing markets.

Products must work in cold, wet soils. 

Objectives1. Identify Pythium spp. associated with poor stands in organic vegetable crops in the Columbia Basin.

P. ultimumP. oligandrumP. catenulatum

P. intermedium

P. splendens P. camurandrumP. diclinum

P. radiosum

P. inflatunP. sylvaticum

P.aristosporum To beidentified

P. dissotocumP. violae

P. echinulatum

P. torulosum

P. adhaerens

P. middletonii

Pythium species identified (37 certified organic fields in Columbia Basin)

P. torulosum

P. irregulareP. abappressorium

Objectives1. Identify Pythium spp. associated with poor stands in organic vegetable crops in the Columbia Basin.

P. ultimum24.6 %

P. violae3.3 %

P. irregulare 15.1%

P. abappressorium

4.9 %

Pythium species identified (37 certified organic fields in Columbia Basin)

15.1%4.9 %

Objectives

2. Evaluate seed and drench treatments for control of damping‐off in organic pea crops.

Methods: 2011 Field trial locations

Boardman, Oregon

Soap Lake, Washington

Mount Vernon, WashingtonMount Vernon, WashingtonMount Vernon, WashingtonMount Vernon, Washington

MethodsTreatments: Boardman and Soap Lake trials (OMRI listed) 

Seed treatments Drench treatmentsSeed treatments Drench treatments

Acadian Marine Seaplant Extract Serenade Soil

Actinovate STP Soilgard 12Gg

HeadsUp Plant Protection Stimplex Biostimulant

Mycoseed Treat Water drench (control)

Mycostop Mix

Natural II CO2 backpack sprayer

Nordox 75 WG Prestop WP

Primed seeds

T‐22 HC

Non‐treated seeds (control)

Methods

Seed treatments Drench treatments Control treatments

Treatments at Mount Vernon trial

Acadian Marine Seaplant Extract Serenade Soil Apron XL

Actinovate STP Soilgard 12G Non‐treated seeds (NTS), inoculated soilHeadsUp Plant Protection Stimplex BiostimulantHeadsUp Plant Protection Stimplex Biostimulant

Mycoseed Treat NTS, inoculated soil + water drenchMycostop Mix CO2 backpack sprayer

Natural II Prestop WP NTS, non‐inoculated soil

Nordox 75 WG NTS, non‐inoculated soil + soil‐oatmeal carrierPrimed seedsPrimed seeds

T‐22 HC

Germains’ II

Prestop Mix

Inoculated with Pythium ultimum

MethodsPlanting  Boardman – Bistro

Soap Lake BoogieSoap Lake – BoogieMount Vernon – Ice Pack

MethodsDrench applications at planting and 14 dap

Methods

Weekly stand count 14 – 35 dap

Sampling and isolation ofSampling and isolation of pathogen from roots  

35 dap 

MethodsRoot rot rating, height, and shoot dry weight

at full bloomat full bloom

Rating scale: 0 ‐ 5 (0 = no symptoms & 5 = dead plant)

Methods

Harvest

Methods

Removal of seeds from pods

Seed weight  Tenderometer reading 

Results: Boardman trialEmergence

Ave. = 35% emergence (35 dap) Poor stand = Rhizoctonia and PythiumPoor stand = Rhizoctonia and Pythium

Results: Boardman trialYield (lb/A)

Results: Soap Lake trialEmergence

Ave. = 81% emergence 

Results: Soap Lake trial Yield (lb/A) 

Results: Mount Vernon trialEmergence

l d i h hi l iInoculated with Pythium ultimum

Results: Mount Vernon trialYield (lb/A)

20.00% Increase in Emergence

Compared to Non-treated Seed15.00

Nordox 6 4

Compared to Non-treated Seed

10.00

Nordox 6.4 

Nordox 6.4 + Corn Flour

5.00

0.002007 2008A 2008B 2009A 2009B 2011A 2011B 2011C

‐5.00

‐10.00

40.00

50.00

% Increase in Yield Compared to Non-treated Seed

30.00

20.00

N d 6 4

10.00

Nordox 6.4 

Nordox 6.4 + Corn Flour

0.002007 2008A 2008B 2009A 2009B 2011A 2011B 2011C

‐10.00

‐20.00

SummaryThree field environments:

• high disease pressure (Boardman trial)• low disease pressure (Soap Lake trial)• inoculated (cold and wet) site (Mount Vernon trial)

High disease site: Nordox and primed seed increased emergence Primed seed increased yield

Low disease site: No benefit from seed treatmentsDrench treatments reduced emergence 

Inoculated site: No treatment worked against Pythium;Primed seed reduced emergence.

l i d d i i h d i lConclusion: Nordox and priming showed potential for damping‐off control.

Future work

Growth chamber trials: optimize primingGrowth chamber trials: optimize priming protocol, evaluate combined treatments (e.g., priming and Nordox).

2012 field trials: more effective seed ( l b )treatments (alone and in combination) 

from 2011 field data.

Other aspects of damping‐off management.

Plant Disease Management Report (PDMR) vol. 6

Acknowledgement

•WSU CSANR•Organic vegetable growers and processors in WA and OR

•Manufacturers and distributors of the organic products

Some of the pesticides discussed in this t ti t t d d i t l presentation were tested under an experimental

use permit granted by WSDA.Application of a pesticide to a crop or site that Application of a pesticide to a crop or site that is not on the label is a violation of pesticide law and may subject the applicator to civil penalties m y j pp p

up to $7,500.In addition, such an application may also result

in illegal residues that could subject the crop to seizure or embargo action by WSDA and/or the

U S Food and Drug AdministrationU.S. Food and Drug Administration.It is your responsibility to check the label

before using the product to ensure lawful use before using the product to ensure lawful use and obtain all necessary permits in advance.