Label Group Numbers Guides to Resistance Management

Label Group Numbers How they made it to Labels Where they come from Understanding them Using them

Purpose of the group numbers Resistance management guidelines for pesticides. Resistance: A pest once controlled by a pesticide and is no longer controlled by that pesticide. Michigan now has 24 resistant weed species!

Group numbers are for several pesticides - this presentation is focused on herbicides

On the Label - upper right corner GROUP1HERBICIDE GROUP2HERBICIDE GROUP3HERBICIDE GROUP4HERBICIDE GROUP5HERBICIDE GROUP6HERBICIDE GROUP7HERBICIDE GROUP8HERBICIDE GROUP9HERBICIDE GROUP10HERBICIDE GROUP13HERBICIDE GROUP14HERBICIDE GROUP15HERBICIDE GROUP16HERBICIDE GROUP19HERBICIDE GROUP22HERBICIDE GROUP27HERBICIDE

A long journey to the label August, 2001 EPA issued guidance for voluntary pesticide resistance management labeling guidelines Align with other global resistance management systems - international harmonization

Resistance Action Committees Industry technical committees: HRAC - Herbicide Resistance Action Committee Alliance with Weed Science Society of America HRAC system is alphabetic WSSA system is numeric - Canada started with numeric Both groups support a world-wide data base of herbicide resistance:

The other Resistance Action Committees IRAC - Insecticide Resistance Action Committee FRAC -Fungicide Resistance Action Committee

EPA’s Goal Ensure users are fully informed about resistance management while making clear that compliance is not required Direction For Use headings: “Resistance Management Recommendations” “box” the statements to clearly segregate the information from mandatory use instrictions

Label herbicide resistance management statements - What can happen This is a Group _ herbicide. Any weed population may contain or develop plants naturally resistant this product and others in Group _. Weed species with acquired resistance to group _ herbicides may eventually dominate the weed population if Group _ herbicides are used repeatedly in the same field or in successive years as the primary method of control for the target species. Total loss of control of the target species product or others in the Group is possible.

Label herbicide resistance management statements - How to delay resistance Avoid consecutive use of the product and others in the Group.

How to delay resistance Tank mix or use premixes of herbicides from different Groups

How to delay resistance Base herbicide use on a comprehensive IPM program

How to delay resistance Monitor application sites for weeds not dying

How to delay resistance Contact your extension specialist, certified crop advisors and/or the manufacturer for integrated weed management recommendations for specific sites or resistant weed biotypes

ACCase inhibitors Mode of Action - Lipid synthesis inhibitor Prevents the formation of fatty acids, which are essential for the production of lipids. Lipids are vital in the integrity of cell walls and thus new plant growth AI (Trade names) sethoxydim (Poast, Poast Plus) clethodim (Select Max) quizalifop (Assure II) fluazifop (Fusilade II & DX, component in Fusion), fenoxaprop (component in Fusion) A grass burndown herbicide - no resistant species in MI GROUP1HERBICIDE

Amino Acid Synthesis Inhibitors ALS Inhibitors - metabolic pathway blockers imazapyr (Arsenal, Habitat, Sahara - w/diuron) imazapic (Plateau) halosulfuron (Manage, Sedge Hammer) sulfosulforon (Certainty) Resistant species: Palmer AmaranthGiant Foxtail Tall Water HempKochia Common Ragweed Marestail/Horseweed GROUP2HERBICIDE

Amino Acid Synthesis Inhibitors EPSP Synthase inhibitor - metabolic pathway blocker glyphosate (Roundup, Roundup QuickPro, Rodeo, Trailblazer) Resistant species: Palmer AmaranthGiant Foxtail Tall Water HempKochia Common Ragweed Marestail/Horseweed GROUP9HERBICIDE

Seedling Growth Inhibitors Inhibits a protein called tubulin which prevents mitosis pendimethalin (Pre-Em, Penncap) trifluralin (Treflan) pronamide (Barricade,Kerb) No resistant species reported in Michigan GROUP3HERBICIDE

Growth Regulators Synthetic auxins 2,4-D (Weedone, 2,4_D Amine &Ester + others) MCPA (Weedar + others) MCPP (MCPP4 Amine + others aminocyclopyrachlor (Perspective, Streamline) aminopyralid (Milestone) clopyralid (Confront, Lontrel, Transline) dicamba (Vision + others) quinclorac (Drive, QuinPro) fluroxypyr (Escalade) triclopyr (Garlon 3 &Garlon Ultra 4L, GROUP4HERBICIDE

Growth Regulators Synthetic Auxins - these herbicides disrupt hormone balance and protein synthesis in plants, leading to a variety of plant growth abnormalities Resistant species Wild Carrot Lambsquarter GROUP4HERBICIDE

Dicamba vs. Acorn Squash

Photosynthesis Inhibitors These herbicides block the photosynthetic process, thereby preventing the conversion of sunlight into chemical energy - block photosynthetic electron transport atrazine (AAtrex - RUP) Resistant species - Velvetleaf, Powell Amaranth, simazine (Princep) Purslane, Groundsel, Prostrate Pigweed bentazon (Basagran) bromoxynil (Buctril, Moxy, others) diuron (Direx, Karmex) will be RUP in MI GROUP5HERBICIDE GROUP6HERBICIDE GROUP7HERBICIDE

Cell Membrane Disrupters These herbicides disrupt cell membranes - “Burn Downs” Carfentrazone-ethyl (Quicksilver T&O, Square One w/quinclorac) Sulfentrazone (Speed Zone, Q-4. Dismiss, Oust) Flumioxazin (BroadStar, SureGuard) Lactofen (Cobra) diquat (Reward) paraquat (Gramoxone -RUP) Some reported resistance in aquatic - duckweed, Eurasian Watermilfoil GROUP14HERBICIDE GROUP22HERBICIDE

Pigment Inhibitors -Bleachers HPPD inhibitors - Recent developments for resistant weeds mesotrione (Tenacity, Calisto) isoxaflutole (Balance) Right now limited Section 18 for Ag GROUP27HERBICIDE

Mesotrione vs. Tomatoes

Pigment Inhibitors PDS Inhibitor fluridone (Sonar) -Aquatic Herbicide GROUP12HERBICIDE

Nitrogen Metabolism Inhibitor - bleaching Glutamine Assimilation Inhibitors - This herbicide blocks the enzyme glutamine synthetase, thus preventing the conversion of ammonia into amino acids Ammonia builds to toxic levels glufosinate (Finale, Liberty) GROUP10HERBICIDE

Glufosinate vs. Flowers

Label Group Numbers How they made it to Labels Where they come from Understanding them Using them