New Developments in Cool Season Vegetable

Weed Control

• Richard Smith, Vegetable Crop and Weed Science Farm Advisor, Monterey County

Weed issues can be moderate to low depending on the rotation• Quick & multiple rotation give growers some

advantages to managing weeds• Some rotations such as baby vegetable mature before

weeds can effectively set seed• Some weeds, such as purslane, shepherd’s purse and

burning nettle can still thrive and be quite problematic

2016 Herbicide Evaluations• Low rates of Kerb for baby lettuce• Zidua (pyroxasulfone) studies Celery Leeks, onions & garlic peppers

• Materials for automated thinner/weeders• Spin-Aid evaluations on spinach• Post transplant applications of Goal Tender

for Brussels sproutsAll available on the UCCE Monterey County Website: Veg/Weed Program

Evaluation of low rates of Kerb

Chart1

PurslanePurslanePurslane

Sow ThistleSow ThistleSow Thistle

0.5 lb ai

1.0 lb ai

untreated

3.8

0.5

20

5

6

3

Sheet1

0.5 lb ai1.0 lb aiuntreated

Purslane3.80.520

Sow Thistle563

Category 33.51.83

Category 44.52.85

Mechanical Weed Control Studies

Finger Weeders

• Invented by the Buddingh company and manufactured in Michigan

• There are European versions of this tool made by the Kress (Germany) and Steketee (Netherlands) Companies

Buddingh Co. Kress & Steketee

Standard cultivation Leaves seedline untouched

Finger WeederDisrupts soil in the seedline

Weed Evaluation of Finger Weedersin Transplanted Radicchio

Gilroy, 2009

Treatment WeedCountPost

Cultivation

PercentWeed

Removal

WeedingTimeAug 7

Weeding Time

Aug 14

Total Hand

weeding time

Standard 40.3 0.0 8.4 6.9 15.3Finger Weeders

16.9 64.0 5.9 5.7 11.6

Finger Weeders• Finger weeders are nothing new, but

access through dealers is fairly recent• Approximately $500/seedline• Sources: Buddingh Weeder Company European designs:

• Sutton Ag (Salinas) Steketee• KULT (Gordonville, PA) Kress

Milestones in Technological Developments

• Over the past 100 years there have been steady improvements in precision of mechanical seeding, cultivation, etc.

• In the last 10-15 years a jump forward has come about due to developments in GPS, computer processing and machine vision

Thinners and Weeders• Automated thinners and weeders

basically use the same technology• They use a camera that captures an

image• The computer processes the image to

determine crop: based on plant size, spacing, etc

• At present they cannot readily distinguish weeds from crop

• That will soon change

Crop/Weed Classification - Size and Location

Mantius Ag Technologies

Ag Mechtronix

Blue River

Vision Robotics

Harvest Moon Automation

(mechanical)

Automated Thinners

Area treated with herbicide to remove plants

Area treated with herbicide to remove plants

A safe zone is established to protect the “keeper” plants

Weeds may survive in the safe zone

Spray Material Options on Lettuce

• Registered on lettuce: Glyphosate Gramaxone Scythe Shark

• Fertilizers: Salt based

• AN20, UN32, Ammonium thiosulfate, Acid based materials

Acid based• NpHuric

• Other materials Sulfuric acid

• Organic herbicides

Material Rate 2 days after application Suppress 6% v/v 69.9Suppress 6% v/v @pH-6.5 68.5Suppress 9% v/v 68.5Suppress 9% v/v @pH-6.5 90.1Scythe 9% v/v 81.2Rely 29 oz/A 31.1Rely 43 oz/A 32.5Shark 1 oz/A 89.127-0-0-5 37 gal/A 67.927-0-0-5MSO

37 gal/A1% v/v 93.9

SF exp. 12% v/v 77.4Untreated --- 0.0

Material Rate 8 days after application Suppress 6% v/v 62.2Suppress 6% v/v @pH-6.5 60.7Suppress 9% v/v 64.6Suppress 9% v/v @pH-6.5 80.1Scythe 9% v/v 73.4Rely 29 oz/A 96.1Rely 43 oz/A 97.5Shark 1 oz/A 96.727-0-0-5 37 gal/A 71.927-0-0-5MSO

37 gal/A1% v/v 94.6

SF exp. 12% v/v 70.9Untreated --- 0.0

Time to Thin and Time to Weed & Remove Doubles

Method Thinninghrs/A

Weed/Double hrs/A*

Total Timehrs/A

Automated 0.9 6.6 7.5Hand 6.6 5.3 11.9

*Automated thinning probably took more time because it left moredoubles than hand thinning:

Automated: 1,024 plants/AHand: 148 plants/A

Doubles left by machine

Thinned plant

RobovatorFrank Poulsen Engineering

Denmark

Automated WeedersBoth Use Split Knife Mechanism

IC SteketeeNetherlands

Island of undisturbed soil is left around the plant; this

undisturbed area can be adjusted to be more aggressive or less

Automated Weeder Evaluation Summary

lettuce and weed plant/A pre and post autoweeder

Timing Lettuceplants1000’s

Weeds1000’s

Pre weeding

37.3 13.5Post weeding 35.2 6.6

Automated Weeder Evaluation Summary

Hand weeding time and lettuce plant wt

MeanTreatment Hand

WeedHrs/A

CropWtlbs

Mechanical weeder 6.1 1.73No mechanical weeder 9.7 1.90

New Developments in Cool Season Vegetable Weed Control Slide Number 22016 Herbicide EvaluationsEvaluation of low rates of KerbMechanical Weed Control StudiesFinger WeedersSlide Number 7Weed Evaluation of Finger Weeders �in Transplanted Radicchio�Gilroy, 2009Finger WeedersMilestones in Technological DevelopmentsThinners and WeedersSlide Number 12Slide Number 13Slide Number 14A safe zone is established to protect the “keeper” plantsSpray Material Options on Lettuce Slide Number 17Slide Number 18Time to Thin and Time to Weed & Remove DoublesSlide Number 20Slide Number 21Slide Number 22Automated Weeder Evaluation Summary�lettuce and weed plant/A pre and post autoweederAutomated Weeder Evaluation Summary�Hand weeding time and lettuce plant wt