Weed ControlTopic 2044

Mr. Christensen

Typical Michigan Weed Seed Production

Weed seeds/plant weed density crop

Velvetleaf 400-1,500 90 corn

Giant foxtail 2,500 100 corn

Common

Lambsquarters 57,000 8 soybean

Weed Seed Fate

From Michigan Field Crop Pest Ecology and Management-Michigan State University Extension Bulletin E-2704

Integrated Pest Management

• Integrated pest management--is the use of all appropriate and economical strategies to manage pests and their damage to acceptable levels with the least disruption to the environment.

Integrated Pest Management

• Determine goals• Pest Monitoring-what kind, how many-

timing• Pest Identification and threshold/action

levels• Control strategies available, implementation

and evaluation of success or failure• Record keeping

Techniques Used in Pest Management

• Natural controls-climate, natural enemies, geographic barriers, food and water supply and shelter

• Applied Controls-Host resistance, biological control, cultural control, mechanical control, habitat modification and sanitation and chemical control

Methods of Weed Control

• Cover crops—weeds don’t have a space to grow.

• Crop rotation—The more diverse the rotation the less opportunity there is for weed population to grow.

• Tillage—No till leaves weed seeds on or near the soil surface, seeds in the germination zone decrease.

Methods of Weed Control

• Planting date—Weed competitiveness can change with planting date.

• Crop plant population and row spacing-Heavier planting limits light for weed germination.

• Rotary Hoeing—Removes small weeds and lets the crop get a head start.

• Cultivation—Do not cultivate if weeds are not a problem or aeration is not needed it can cause weed seeds to be brought into the germination zone.

Cultivation

Chemical Controls

• Algaecide-Algae• Biocide-Microbial Org.• Fungicide-Fungi• Insecticide-Insects &

Related animals• Herbicide-Weeds• Miticide-Mites• Nematicides-Nematodes

• Rodenticide-Rodents• Avicide-Birds• Piscicide-Fish• Molluscicide-Slugs/

snails• Ovicide-Eggs of

organisms• Predacide-Vertebrates

Other Chemical Controls

• Growth regulator-modifies plant or insect development

• Defoliant-removes plant foliage• Desiccant-dries plant foliage• Repellent-diverts a pest• Attractant-lures a pest• Pheromone-attract pest or disrupt behavior• Sterilan-renders pest unable to reproduce

Pesticide

• Protectants• Sterilants• Selective• Nonselective• Broad-Spectrum

• Contact• Systemic• Persistent• Nonpersistent

Pesticide Categories

• Non-Selective—Kills or adversely affects many organisms (Glyphosate)

• Selective—Effective against one type of organism and not another.

• Broad-Spectrum—Pesticides that control a wide range of pests (multiuse).

• Contact—Kill or adversely affect the target organisms by simple contact.

Pesticide Categories

• Systemic—Absorbed by one part of an organism and distributed internally to other parts of the organism for action (heartworm control in dogs)

• Persistent—Remain active for a period of time giving residual protection.

• Non-persistent—Control pests at time of application and breakdown quickly.

Pesticide Categories

• Protectants—Pesticide applied to prevent pest establishment.

• Sterilants—Pesticide that manage pests by rendering them incapable of normal reproduction.

Chemical Weed Control Modes of Action

• Growth Regulators—Banvel, Stinger, 2,4-D (Amine and Ester)

• Amino Acid Synthesis inhibitors (ALS synthase enzyme)—Accent, Broadstrike, Harmony, Pursuit.

• Amino Acid Synthesis (EPSP synthase enzyme) inhibitors—Glyphosate (Honcho, Ranger, Roundup)

Chemical Weed Control Modes of Action

• Lipid (Acetyl-CoA carboxylase enzyme) inhibitors—Assure II, Fusion, Poast, Whip

• Seedling root (tubulin protein) inhibitors—Balan, Prowl, Sonolan, Treflan

• Seedling Shoot inhibitors—Arena, Dual, Eptam, Lasso, Surpass, Frontier

Chemical Weed Control Modes of Action

• Photosynthesis (D-1 Quinone-binding protein) inhibitors—Atrazine, Basagram, Bladex, Buctril, Spike.

• Membrane disrupters—Avenge, Cyclone, Gramoxone Extra, Cobra, Reflex, Blazer

• Pigment inhibitors—Command, Zorial

• Why are their so many Modes of action?

• What advantages do they give the grower.

• Some are effective against different weeds.• Timing of the pest problem may dictate

what can be used (pre-emergence, post emergence)

• Some last a long time and cause safety problems with the fruit or following crops

• Using the same chemicals may develop resistance in the pest

Developing Resistant Pests

From Michigan Field Crop Pest Ecology and Management-Michigan State University Extension Bulletin E-2704

Glyphosate Resistant Weeds

Lambsquarters

Black nightshadeWaterhempYellow nutsedgeVelvetleafCommon Ragweed

Successful Farming February 2004

Marestail