Auxin Herbicides Best Management Practices Training developed by

Auxin Herbicides Best Management Practices Training developed by Alan York, NCSU Training approved by N. C. Dept. Agric. & Cons. Serv.

Purpose of Training § Neither encouraging nor discouraging use § Not trying to scare you; intent is to raise awareness of potential problems and how to avoid them § Not discussing weed control systems § Provide applicators with information needed to avoid off-target deposition (with emphases on new auxin technologies) • • Prevent damage to your crops Prevent damage to your neighbor’s crops (and your wallet)

Purpose of Training § Provide applicators with information needed to avoid off-target deposition • Prevent damage to your crops • Prevent damage to your neighbor’s crops (and your wallet) § Future availability of technology depends upon how well we manage off-target deposition (time-limited registrations for Engenia and Xtendi. Max; 2 years; extension of registration depends on how much drift we have)

Enlist & Xtend technologies: We want to keep them!

Purpose of Training § Provide applicators with information needed to avoid off-target deposition • Protect your crops • Protect your neighbor’s crops (and your wallet) § Future availability of technology may depend upon how well we manage off-target deposition § Growers must demonstrate they can use the technology responsibly § Goal is ZERO off-target issues

New Technologies Traits Crops Resistant to: Enlist Cotton 2, 4 -D, glyphosate, glufosinate Soybean Xtend Corn 2, 4 -D, glyphosate, FOP’s Cotton dicamba, glyphosate, glufosinate Soybean dicamba, glyphosate

New Technologies Traits Crops Herbicides Registration status Enlist Cotton Enlist Duo Registered Jan 2017 Soybean (2, 4 -D + glyphosate) Corn Xtend Cotton Engenia (dicamba) Registered Dec 2016 Soybean Xtendi. Max (dicamba) Registered Nov 2016 Fe. Xapan (dicamba) Registered Feb 2017

Dicamba ≠ 2, 4 -D They are not interchangeable

T. Barber T. Whaley A. York

What is an “auxin-sensitive” crop? Basically any broadleaf crop that does not have Enlist or Xtend trait Dicamba (1/900 th full rate) 2, 4 -D amine; 1350 feet upwind

Visual Sensitivity: Example Dicamba Lower Moderate Severe Broccoli Cabbage Kale Mustard Pecan Turnip Cantaloupe Cucumber Peach Peanut Squash Cotton Pepper Tomato Watermelon >1/75 X 1/75 -1/300 X 1/300 -1/800 X Extreme Grapes* Lima Bean Southern Pea Snap Bean Soybean Sweetpotato* Tobacco* < 1/800 X Herbicide Rate of Visually Detectable Injury For relative comparison, tomato, squash, and watermelon response to Roundup would be in the “lower” category. *Data from literature; all other data generated in GA field studies

Visual Sensitivity: Example 2, 4 -D Lower Moderate Severe Extreme Broccoli Cabbage Kale Mustard Onions Turnip Cantaloupe Canola Cucumber Peaches Peanut Pecan Squash Pepper Tomato Watermelon Cotton Grapes* Sweetpotato* Tobacco* 1/300 -1/800 X < 1/800 X >1/75 X 1/75 -1/300 X Herbicide Rate of Visually Detectable Injury For relative comparison, tomato, squash, and watermelon response to Roundup would be in the “lower” category. *Data from literature; all other data generated in GA field studies

Types of Labels Container label Supplemental label 24(c) Special Local Need label

§ Applicator must follow all labeling That includes: Container label Supplemental label NC 24(c) label § Applicator must have all the above in possession when applying.

York, 2015

Impacts of Off-target Deposition ► Reduced yield • Rate of exposure • Growth stage at exposure • Growing conditions at and after exposure

Expression of Auxin Injury § Auxin herbicides affect expanding plant tissue, or new growth. § New growth must occur before symptoms are observed. § Symptoms develop slowly. • First observed about a week after exposure; max out at 3 to 4 weeks after exposure.

Impacts of Off-target Deposition ► Reduced yield ► Marketability of tobacco, fruits and vegetables (high value crops) • Has a tolerance been established? • Regardless of residue level, will buyer accept crop? (particular concern with tobacco and vegetables) • Visible injury may occur with non-detectable residue levels “If we see injury, we don’t want it. ”

Sources of Off-Target Deposition ► Vapor drift ► Sprayer contamination

Spray Drift vs. Vapor Drift Spray drift (also called particle drift) is the physical movement of fine spray droplets by wind after the droplets leave the nozzle and before they reach the intended target.

Spray Drift vs. Vapor Drift Vapor drift is movement of herbicide in a gaseous form after it has been deposited on the target. After deposition, the herbicide changes from a liquid or solid form into a gas, and the gas moves off-target with wind. Can occur hours or days after application.

Sources of Off-Target Deposition ► Vapor drift Chemistry, Formulation Temperature, Humidity ► Spray drift ► Sprayer contamination

Temperature and Vapor Drift • No temperature restrictions on labels of new 2, 4 -D and dicamba products. • However, exercise more caution when temperatures reach 90 F or above, especially if sensitive crops in the neighborhood.

Sources of Off-Target Deposition ► Vapor drift Critical! Chemistry, Formulation Temperature, Humidity ► Spray drift ► Sprayer contamination

Herbicides for New Auxin-Resistant Cotton and Soybean Products Xtendi. Max with Vapor. Grip Technology Fexapan plus Vapor. Grip Technology Active ingredients dicamba, DGA* salt Engenia dicamba, BAPMA* salt Enlist Duo 2, 4 -D, choline salt + glyphosate, DMA* salt * DGA: diglycolamine; BAPMA: N, N-bis-(aminopropyl) methylamine; DMA, dimethylammonium.

To reduce potential for vapor drift: • New products specifically for Xtend or Enlist crops have reduced potential for vapor drift compared with other formulations on market. • Only brands of dicamba or 2, 4 -D specifically registered for use on Xtend or Enlist crops can be used. § Important to use only the brands specifically registered for Xtend or Enlist crops.

Sources of Off-Target Deposition ► Vapor drift – use of registered formulations is our best defense ► Spray drift ► Sprayer contamination

Sources of Off-Target Deposition ► Vapor drift ► Spray drift Nozzle type Wind speed Spray pressure Land terrain Sprayer speed Humidity Boom height Spray volume Tank mixes; adjuvants Buffer areas ► Sprayer contamination

Nozzle type Spray Pressure Sprayer Speed Influence Spray Droplet Size

Droplet size order Standard Flat Spray e Fin XR Tee. Jet® ar t l U Turbo Tee. Jet® Induction Turbo Tee. Jet® AIXR Tee. Jet® Air Induction Tee. Jet® e rs a o C