Regional Watermelon Meeting

Weed Control in Watermelon: Strategies with Herbicides, Cover Crops and Rotation

Jim HeiserUniversity of Missouri

Fisher Delta Research Center

Introduction

• Getting Started

• Chemical Control

• Rotation Control Measures

• Cover crops

• Tillage

• Fertility

Getting Started

www.agroecology.org

• Multiple benefits

• Weed suppression

• Build soil

• Hold fertility

• Improve pollination

• Termination

• Excessive residue

Cover Crops

• Types• Grass/cereal

• Tall

• Termination

• Legume• “Free” N

• Become ‘weeds’

• Other broadleaf• Compaction

• Termination

• Mixture• Establishment

• Synergism

Cover Crops

• Types

• Grass/cereal

• Tall

• Termination

• Legume

• “Free” N

• Become ‘weeds’

• Other broadleaf

• Compaction

• Termination

• Mixture

• Establishment

• Synergism

Cover Crops

• Winter wheat

• Fall

• Cereal Rye

• NOT ryegrass

• Fall or spring

• Fall tillage

• Winter weeds?

• Cover crop herbicide

Cereal Cover Crops

Extension.missouri.edu

grantcountyweedboard.org

• Termination

• Chemical

• Timing and size

• Rolling/Crimping

• Flowering

• Timing Critical

• Reseed

• Dormancy

Cereal Cover Crops

Gene Stevens

Jim Heiser

extension.missouri.edu

• Crimping• Better kill?• No drift• Suppression

• Difficult• Wind

• Chemical• Easier• Some suppression• Wind

• Poor kill• Reseeding

Cover Crop Termination

• WINTER Rye

• Chemical termination

• Reseeded

• New beds = strip till

• Vetch good but…

• Legumes difficult

• Broadleaves?

My Cover Crop Experience

• Tillage

• Late fall primary

• Shallow in season

• Fertility

• Soil test

• Rapid growth

Tillage and Fertility

Gene Stevens

Introduction

• Getting Started

• Chemical Control

• Rotation Control Measures

Chemical Control

• Limited Choices

• Crop value vs. risk

• “New” programs

Chemical Control

onevegetables.com

cals.arizona.edu

• Bensulide• Bee issues

• Few weeds listed

• Yellows• Placement

• Duration

• Clomazone• Very low rates

Chemical Control

• Carfentrazone, Paraquat, Glypohsate, Flumioxazin• Shielded/spot• Row middles

• Halosulfuron• Pre in direct seeded• 7 day PTran

• Graminicides• Grasses• Oil or surfactant

Chemical Control

• Row middles

• Grass control

• Shielded

• Pre harvest intervals

• Reapply PRE

Post Emerge Chemical Control

• Narrow tolerance

• Calibration essential

• Yield reduction

• By competition

• By injury

Chemical Control Risks

teejet

• Labeling cost $$$$$

• “Minor” crops

• *Azafeniden, Axiom, Thiazopyr, Gallery, Dimension, Harmony• PRE ≈2x rate safe

• Olympus, Envoke

• Olympus, Axiom, Harmony• POST – safer on cantaloupe

Future Options

*K. Umeda, University of Arizona, College of Agriculture 2001 Vegetable Report

• Cotton• Marestail, Palmer, Sandbur, Goathead, etc.

• Soybeans• Same as above

• Better options

• Corn

• Poorly suited

• Best options

Rotation Options

• Cotton and soybean• Keep fighting the good fight!

• Overlap

• Strive for 100% control

• Corn• Try where feasible

• Suitable hybrids

• Cleanup

Rotation Options

• Three year rotation

• “New” ground melons

• Cotton

• Corn

Other Options

southeastfarmpress.com

deltafarmpress.com

• Proper populations

• Varietal selection

• Irrigation and drainage

• Mulch middles

• Early cultivation

Other Factors to Consider

UCANR.edu

• University of Florida

• HS190, Weed Management in Cucurbit Crops

• University of California

• UC Weed Science, Mulching with rolled straw bales

• Texas A&M University

• Russell W. Wallace, The effect of herbicide treatment on direct-seeded watermelons:2003

• Louisiana State University

• 2013 Weed Management Guide

Other Resources

Contact Information

Jim Heiser

Fisher Delta Research Center

PO Box 160

147 State Hwy T

Portageville, MO 63873

(573) 379-5431 (O)

(573) 999-3748 (C)

www.plantsci.missouri.edu/deltaweeds