Endangered Species Act: What will soon change for pesticide labelling and uses?

Endangered Species Act and Pesticides: How will pesticide labels change to protect endangered species?

Wednesday, March 20 at 11 a.m – Webinar

Enacted in 1973, the Endangered Species Act (ESA) requires all federal agencies to consider the impact to threatened and endangered species and their critical habitat when making decisions. The Environmental Protection Agency (EPA) has faced numerous lawsuits for its failure to consider the Act when issuing pesticide registrations—resulting in a 2023 commitment from the Agency’s Office of Pesticide Programs that puts the ESA at the forefront of all future registrations and some registration renewals.

The NYS IPM program at Cornell will be hosting Dr. Bill Chism, Chair of the Endangered Species Act Committee for the Weed Science Society of America (WSSA), to give a webinar on March 20th (at 11 a.m.) with the following objectives:

  • • Inform us about the history of Endangered Species Act (ESA),
  • Discuss the requirements of all Federal agencies to comply with the ESA,
  • Describe the EPA’s current workplan (including the proposed Herbicide Strategy) to meet their statutory obligations,
  • Explains what this might mean for future pesticide labeling efforts.

Registration: Endangered Species Act and Pesticides: An Example | CALS (cornell.edu)

About the Speaker


Bill Chism is the chair of the Endangered Species Act Committee of the Weed Science Society of America (WSSA). He retired after more than two decades with the EPA, where he conducted assessments on the benefits of pesticides to farmers as part of the registration review process. Bill grew up working on a vegetable farm in the Salinas Valley of California. He worked in extension researching weed control research on vegetable crops before earning his PhD in Weed Science from Virginia Tech and spent 10 years working for a pesticide registrant.

 

Update on Xtend-specific dicamba products registration

On February 6, 2024, the U.S. District Court of Arizona vacated the registrations of three dicamba products (Engenia 5L, Xtendimax 2.9L and Tavium 3.39CS) labeled for over-the-top use in Xtend and XtendFlex soybean systems. After several days of uncertainty, we now have guidance from the EPA about use of these products in the 2024 growing season. Based on the Court’s decision, the EPA considers these products to be no longer registered but allows for use of existing stocks under limited conditions:

  • Use of products: The EPA’s “existing stocks order” allows private and commercial applicators to use existing stocks that were acquired by May 31, 2024. Applications of these products are permitted until June 30, 2024, in Xtend brand soybean fields.
  • Distribution and sale: The EPA order limits further distribution and sales of these products to only existing stocks that were in possession of dealers prior to February 6, 2024, to facilitate use of the product by the June 30 deadline. In other words, the major manufacturers/registrants of these products are not allowed to sell them anymore, but any dealers with an existing inventory may sell these products until May 31, 2024, and applicators may spray them, according to their label, until June 30, 2024.
  • Dicamba training: To use any of these Xtend-specific dicamba products, special dicamba training must be done annually to purchase and apply them. Training is reciprocal across brands, meaning an applicator only needs to take one dicamba-specific training each year; no matter what product is used, and which organization does the training. For more information about online dicamba training options and other specifics see:

Keep in mind, other dicamba-containing products such as Clarity, Diflexx, Status, and the many generics cannot be legally sprayed over-the-top of Xtend brand soybeans. However, the use of glyphosate and glufosinate (Liberty, etc.) products can still be used depending on the variety.

Enlist E3 soybean varieties have not been affected by this lawsuit and thus registered 2,4-D choline products (Enlist One and Duo) can be used in that system. These and other 2,4-D products cannot be applied over-the-top in Xtend/XtendFlex soybean systems, otherwise major crop damage will occur.

We will continue to provide updates if more details emerge. The EPA order and summary can be found here: Existing Stocks Order for Dicamba Products Previously Registered for Over-the-Top Use on Dicamba-Tolerant Cotton and Soybean (PDF).

The 2024 Mid-Atlantic Weed Control Guide for Agronomic Crops is now available!

The 2024 Mid-Atlantic Weed Control Guide: Essentials for Agronomic Crops is now available for purchase from Penn State Extension in print ($10) or as a digital download ($8). A bundle that includes both versions can be purchased for $18. More information about this guide is available at https://extension.psu.edu/weed-guide.

Penn State Extension (Dwight Lingenfelter and Dr. John Wallace) produces this publication in cooperation with the University of Delaware (Dr. Mark VanGessel), the University of Maryland (Dr. Kurt Vollmer), Rutgers University (Dr. Thierry Besancon), Virginia Tech (Drs. Michael Flessner and Vijay Singh) and West Virginia University (Dr. Rakesh Chandran).

The guide contains essential tables about herbicide recommendations and general use guidelines for corn, sorghum, soybean, small grains, forages and farmstead.

It also offers herbicide effectiveness ratings on problem weeds such as henbit, horsenettle, horseweed/marestail, palmer amaranth and waterhemp, common pokeweed, common ragweed, giant ragweed, annual ryegrass, broadleaf and curly dock, johnsongrass and shattercane, lambsquarters, milkweed and hemp dogbane, Canada thistle, and other species.

Featuring updated herbicide tables from the 2023-24 edition of the Penn State Agronomy Guide, this condensed, quick-reference manual highlights basic information about herbicide-use recommendations and herbicide effectiveness on common weed species in the region.

Alion herbicide received 24(c) Special Local Need label for use on Highbush Blueberry

Thanks to field research conduct by the Rutgers Specialty crops Weed Science lab and funded by Rutgers NJAES, Bayer CropScience, and the NJ Blueberry and Cranberry Research Council, Alion® herbicide received a FIFRA 24(c) Special Local Need label from the EPA and the NJDEP for use ONLY on dormant highbush blueberry in sandy soils containing greater than 1% organic matter. The new  24(c) Special Local Need label can be found on the Agrian website here.

Alion® (indaziflam) is a Weed Science Society of America (WSSA) group 29 cellulose biosynthesis inhibitor in the alkylazine family. The FIFRA Section 3 label of Alion® allows its use on blueberries that have been established for at least one year but prevents its use on soil with ≥ 20% gravel content or on sandy soil, regardless of soil organic matter content. Thus, prior to receiving the new  24(c) Special Local Need label, Alion® could not legally be applied on New Jersey blueberries that are primarily planted on sandy soils.

The new 24(c) Special Local Need label allows directed application to the soil beneath blueberry bushes planted on sandy soils with some important restrictions:

  • Only apply Alion Herbicide to soil as a dormant application in late fall through early spring before bud swell.
  • Do not use Alion® in highbush blueberry crops grown in sand containing <1 % organic matter content.
  • Do not use on soils with 20% or more gravel content.
  • Do not apply more than a total of 10 fl oz product/A (0.13 lb ai/A) per year on sand containing ≥1 % organic matter content in a 12-month period when used in any highbush blueberry.
  • Do not allow spray to contact green stems, foliage, flowers, or berries or unacceptable injury may occur.
  • When making more than one application per year, allow a minimum of 90 days between applications.

Alion® provides excellent and season-long residual control of annual grasses and broadleaf species due to its long soil persistence with half-life greater than 150 days and low water solubility under acidic soil conditions. Results of a 3-years study conducted on three different blueberry cultivars (Duke, Bluecrop, and Elliott) at the Rutgers P.E. Marucci Center  demonstrated that repeated fall or early spring applications of indaziflam at the 5 fl oz/a labeled rate did not cause injury or reduce commercial yield of blueberry grown on sandy acidic soil. Data generated through this research also showed that fall application of indaziflam consistently provided better weed control than spring applications for species such as horseweed, large crabgrass or narrowleaf goldentop. This suggests that Alion®  applications in New Jersey should be restricted to dormant bushes during the fall season in order to maximize weed control effectiveness while maintaining the highest level of crop safety as compared to spring application. Alion® has no activity on sedge species or perennial weeds. Therefore, it is important to consider rotating to different herbicide modes of action after 1 or 2 years of Alion® application to avoid selecting for weeds that are not controlled by Alion® and prevent potential development of herbicide resistance to indaziflam.

2023 Weed Control with Residual Herbicides for New Jersey Highbush Blueberry

With T3 stage forecasted for the end of March this year, soil-applied preemergence herbicides should be sprayed before blueberry bud break to minimize the risk of crop injury and allow sufficient time for residual herbicide to be “activated” by rainfall.

Soil-applied preemergence herbicides should be applied prior to weed seed germination. If applied to weeds that are already out of the ground, most of these products will not control them if they are not tank-mixed with a postemergence herbicide. Glufosinate (Rely 280), paraquat (Gramoxone and generic formulations) and carfentrazone (Aim) are postemergence herbicides that may be applied with preemergence herbicides with little risk of crop injury. Keep in mind that at least ½” rainfall or irrigation is needed within 7 days after application to move (“activate”) preemergence herbicides into the soil solution. Delaying activation may reduce overall performance if some weeds continue to germinate under low soil moisture conditions or if herbicide at the surface of the soil is susceptible to sunlight breakdown.

Make sure the herbicides you plan to apply will be effective at controlling the weed species in your field by checking the herbicide label. Usually, residual herbicides will suppress weed for 5 to 8 weeks depending on irrigation as well as soil and weather conditions. After this period, another residual herbicide can be needed to control weeds through harvest and could be mixed with postemergence herbicides to control emerged weeds. To reduce the potential of selecting for herbicide-resistant weeds, it is highly recommended mixing two herbicides that belong to two different WSSA (Weed Science Society of America) groups whenever you apply preemergence herbicides.

Please, refer to the 2022-2023 New Jersey Commercial Blueberry Pest Control Recommendations for more information on herbicide rates and use restrictions. https://njaes.rutgers.edu/pubs/publication.php?pid=E265

WSSA group 0 – Unknown Site of Action

  • Devrinol 50DF-XT or Devrinol 2-XT (napropamide) will provide good control of annual grasses and should therefore be tank mixed with a PSII or a PPO inhibitor for controlling broadleaf weeds. Devrinol is rapidly degraded if left exposed on the soil surface, so it should be applied less than 24 hours before a rain event to incorporate the herbicide in the soil.

WSSA group 2 – Acetolactate Synthase (ALS) Inhibitors

  • Solida 25WDG or Matrix 25SG (rimsulfuron) or Sandea 75DF (halosulfuron) are ALS-inhibiting herbicides that have both preemergence and postemergence activity. They control most annual broadleaves but are weak on common groundsel, common lambsquarters and eastern black nightshade. Sandea is ONLY recommended for postemergence control of yellow nutsedge.
  • However, these two herbicides will NOT control ALS resistant weeds (horseweed, ragweed) already widespread in New Jersey. Thus, these herbicides should always be tank mixed with a partner effective at controlling these weeds.

WSSA group 3 – Mitosis Inhibitors

  • Kerb 50WP or Kerb 3.3SC (pronamide) is effective at controlling many annual grass species for 4 to 6 weeks after application. Surflan should not be applied to soils containing more than 5% organic matter. Kerb also helps controlling perennial quackgrass as well as annual bluegrass. If applied to warm soils, Kerb persistence and weed control can be severely reduced; therefore, keep Kerb for fall/winter application when soil temperature remains under 55°F. Do not use Kerb on blueberries that have not been established for about a year.

WSSA group 5 and 7 – Photosystem II (PS II) Inhibitors

  • PS II inhibitors have a broad spectrum of control and will be effective against many broadleaves and annual grasses when applied in spring. Karmex 80DF (diuron) and Princep 4L or Princep Caliber 90WDG (simazine) have relatively low solubility and have been very safe on blueberries. Sinbar 80WDG (terbacil) has a longer residual life in the soil and also is more soluble, so it should be used infrequently on light, wet soils. These herbicides are effective on many broadleaf weed species, including common chickweed, common lambsquarters, common groundsel, henbit, nightshade, redroot pigweed, pineapple weed, shepherd’s-purse, smartweed, and some mustards.  Princep and Sinbar will also control many annual grasses and help suppressing quackgrass. Do not exceed more than 1 lb/A of Sinbar to minimize the risk of crop injury.
  • Trellis 4.2SC(isoxaben) is registered for bearing and non-bearing blueberry. Trellis will be most useful in new plantings for preemergence control of annual broadleaf weeds such as common lambsquarters, ragweed, black nightshade, horseweed and smartweed. It does not control grasses.
  • Velpar 2L or Velossa 2.4L (hexazinone) is very soluble and should not be used on blueberries grown on sandy soils as the risk of crop injury is high with this herbicide.

WSSA group 12 and 27 – Carotenoid Biosynthesis Inhibitors

  • Solicam 80DF (norflurazon) can be applied in fall or early spring primarily for annual grass control and quackgrass suppression. Solicam may also provide partial control of many broadleaf weeds as well as of yellow nutsedge. Do not use Solicam on blueberries that have not been established for about a year.
  • Callisto 4SC or Motif 4L (mesotrione) will control many annual broadleaf weeds as well as annual sedges. It controls large crabgrass but no other grasses, such as goosegrass. Callisto may be used as a broadcast spray between rows to control broadleaves and crabgrass without injuring the fescue sod. However, Callisto CANNOT be applied after the onset of bloom.

WSSA group 14 – Protoporphyrinogen Oxidase (PP0) Inhibitors

  • Chateau EZ (flumioxazin) and Zeus 4XC or Zeus Prime 3.5XC (sulfentrazone) have activity against many annual broadleaf weeds (pigweeds, common lambsquarters, ladysthumb, mallow, shepherd’s-purse) when applied preemergence in spring. Chateau and Zeus Prime XC also have some postemergence activity on newly emerged seedlings of annual weeds. Herbicides containing sulfentrazone will also provide suppression of yellow nutsedge. Chateau has a 7 days pre-harvest interval (PHI) and Zeus Prime XC has a 3 days PHI, allowing these herbicides to be applied later in the season to extend preemergence broadleaves control into summer. Blueberry plants must have been established at least two years prior to use of these herbicides.

WSSA group 15 – Protoporphyrinogen Oxidase (PP0) Inhibitors

  • Dual Magnum 7.6ec (S-metolachlor) has a 24(c) Special Local Need label for blueberry in New Jersey. This herbicide provides preemergence control of many annual grasses and some small-seeded broadleaf annual weeds such as redroot pigweed, nightshade and common purslane. Dual Magnum also suppresses emergence of yellow nutsedge. Use Dual Magnum only on plants established for more than one year, and lower rates are suggested on 2- to 3-year-old plantings.

WSSA group 29 – Cellulose Synthesis Inhibitors

  • Casoron 4G (dichlobenil) is a cellulose synthesis inhibitor recommended for fall application to control many annual and perennial broadleaves, grasses and yellow nutsedge. If left on the soil surface or if applied to warm soil (> 55°F or 70°F depending on Casoron formulation), Casoron can lose much of its activity.
  • Alion 1.67SC (indaziflam) IS NOT LABELED FOR USE ON HIGHBUSH BLUEBERRY GROWN ON SANDY SOILS AND/OR ON SOILS WITH ≥20% GRAVEL CONTENT. Additionally, Alion requires significant rainfall for being activated which is not guaranteed with spring applications. Field trials at the Marucci Center have consistently shown better weed control efficacy with fall applications than spring applications.
  • Casoron 4G and Alion 1.67SC should be used ONLY for fall/winter applications. Plants must be at least one year old before Casoron 4G or Alion 1.67SC should be used.

Recommendations for Under Plastic Mulch Weed Control

Plastic mulch, usually used with trickle irrigation, has many horticultural benefits for summer vegetable crops, and black plastic controls most annual weeds. Mulch does not solve all the weed problems in the field, and creates new challenges for the grower.
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