Rutgers University | New Jersey Agricultural Experiment Station | Pesticide User Responsibility

April 6, 2023

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.

Filed Under: Blueberry Tagged With: , ,
March 14, 2023

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.
Filed Under: Blueberry, Fruit Tagged With: , , ,
March 10, 2022

Tips in Preparation of Herbicide Shortages in 2022 – Tree Fruit and Small Fruit Crops

Thierry E. Besançon, Rutgers University, and Lynn M. Sosnoskie, Cornell University

Many growers in the US have been focused on predicted herbicide shortages in the upcoming field season. While the primary concerns have surrounded glyphosate and glufosinate, there is increasing apprehension that active ingredients of importance to tree fruit and small fruit growers may also be affected. Although the supply change is dynamic, chemical stocks may become, and remain, tight at the local or regional level as growers try to fill gaps in their toolboxes. As spring residual herbicide are soon to be applied, please consider the following when planning for the 2022 season.

Important note: Not all herbicides are available in all crops in both New Jersey and New York. Always review current labels before applying products

 

Successful Weed Identification, Regular Scouting and Detailed Field Records are Crucial for Optimizing Weed Control Success

  • The first step in developing a novel herbicide program is knowing what species are present and determining which combination of products will be the most effective (and affordable) at suppressing them. Not all active ingredients are equally useful against all species and careful consideration needs to be paid to each chemical’s spectrum of control. Please, carefully review herbicide effectiveness tables for various weed species that are available in the 2022 Commercial New Jersey Pest Control Recommendations for blueberry, tree fruits or grape (https://njaes.rutgers.edu/pubs/). Similar tables are available in Cornell’s weed control guides (PMEP Guidelines (cornell.edu))

Familiarize Yourself with Chemical Substitutes before Applying Them over Many Acres

  • Some switches may be intuitive (e.g. using Poast (sethoxydim) or Fusilade (fluazifop) in place of clethodim where allowed) while others may be more complicated (e.g. using a tank-mixture in place of a single product). In addition to knowing a product’s target species, become acquainted with each herbicide’s labeled rate structure and spray volume, use patterns (e.g. application timing), environmental limitations (e.g. soil type or temperature restrictions), adjuvant requirements, and potential interactions with tank-mix partners. Not all chemicals are compatible with each other, and antagonism can reduce weed control efficacy while enhancing crop injury concerns. Contact your Extension Specialists if you have any doubt regarding physical compatibility and efficacy of herbicides mixtures.

Soil-Applied Preemergence Herbicides are Critical Tools

  • Soil-applied preemergence herbicides are very useful tools for suppressing weeds that emerge with the crop; these plants are the most injurious as early season competitors are very likely to reduce yields. Like postemergence products, soil-applied herbicides must be carefully selected to balance crop safety with weed control needs. Pay attention to rate requirements according to soil type, as this can influence both efficacy and injury. Preemergence herbicides need to be moved (aka activation) into the soil solution (via either rainfall or irrigation) where they are taken-up by emerging weed seedlings; delays in activation can reduce overall performance if some weeds continue to germinate and emerge under low soil moisture conditions. Delays may also facilitate the degradation of some products susceptible to breakdown in sunlight (i.e. photolysis). Be aware that trickle irrigation may cause less effective and less consistent weed control by washing off residual herbicides from top soil where weeds germinate, thus increasing herbicide application costs. When possible, use overlapping residual products to suppress weed emergence throughout the season. Some active ingredients may have both preemergence and postemergence activity (e.g. flumioxazin (Chateau) or simazine (Princep)).

Timing Matters

  • Postemergence (i.e. foliar) weed control should be undertaken when weeds are small and succulent. Herbicide labels will have specific recommendations regarding the optimal size for treatment. For instance, clethodim (Select Max) and sethoxydim (Poast) have a maximum height or lateral growth requirement of 6 inches for effective control of goosegrass or crabgrass. Weeds are more sensitive to control measures when they are small and succulent, so rapid identification and management will improve control success. Because many foliar-applied herbicides can also damage crops, as well, always follow label guidance to reduce risk of injury.

Optimize Herbicide Application Rate for Postemergence Applications

  • Target using the lowest effective herbicide rate to stretch your herbicide supply. For example, instead of applying 32 or 44 oz/acre of a glyphosate brand product, consider using the standard rate on the label such as 22 oz/acre for Roundup PowerMax. Again, timing of application with regards to weed size will be critical to optimize your herbicide supply. The smaller the weeds, the less herbicide you will have to apply to control it! Therefore, frequent scouting as highlighted above will be very important to optimize your herbicide application and stretch your herbicide supply.

Don’t Skimp on Adjuvants

  • If herbicides are going to be in short supply, then there may be fewer shots to control weeds. If there are fewer shots available, make every shot count as much as possible. Follow label recommendations regarding the inclusion of water conditioners, surfactants, etc…, to maximize product efficacy. Refer to point number two about potential compatibility concerns when tank-mix partners are involved.

Get Perennial Weeds under Control

  • Perennial species such as Canada thistle, goldenrods, bindweed or quackgrass are frequent and troublesome weeds of tree fruit and small fruit crops. Because control of these weeds requires the use of systemic herbicides that may be in short supply (i.e. glyphosate), appropriate timing of application will be critical to maximize herbicide efficacy. For example, Canada thistle should be sprayed with a systemic herbicide in late spring after flower buds started to develop whereas Virginia creeper or poison ivy should be targeted in mid- to late summer after vines flowers but before fall color appears in the foliage. Use effective alternatives such as clopyralid (Stinger) for control of leguminous and composite (e.g. Canada thistle) weeds or soil-applied pronamide (Kerb) for control of perennial grasses where authorized. This may help you to reserve the use of glyphosate for perennial weeds that cannot be efficiently controlled by other products.

Consider Non-Chemical Weed Control Strategies When and Where Appropriate

  • This includes hand weeding, cultivation, and mowing practices. Like herbicides, these practices are not effective against all species at all times. For example, while cultivation can control many weed seedlings, particularly at the white-thread stage, soil disturbance is less effective against well-developed plants. In the case of some perennials (for instance, field bindweed or Canada thistle), cultivation contributes to break up and disperse root fragments within and across fields, facilitating dispersal. Ultimately, plan for hand-weeding escapes prior to the weeds setting seeds as this will help reducing the weed seedbank for future growing seasons.

Plan Ahead Now!

  • 2022 could be a difficult year if many crop production and protection chemicals are limited. Herbicide shortages could impact weed control success in the coming growing season…and beyond. Weeds that are not controlled in 2022 will set seed that will cause problems in the future. Planning now can help with weed management in both the short and long term.
Filed Under: Blueberry, Cranberry, Fruit, Strawberry, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: , , , , , , ,
March 10, 2022

2022 Update on Weed Control with Preemergence Herbicides for Highbush Blueberry

With a looming shortage of some postemergence herbicides, effective use of soil-applied preemergence herbicides becomes increasingly important in 2022. As the T3 stage is forecasted for early April, soil-applied preemergence herbicides should be sprayed before blueberry bud break.

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 mixed with a postemergence herbicide. Glufosinate (Rely 280), paraquat (Gramoxone) and carfentrazone (Aim) are postemergence herbicides that may be applied with preemergence herbicides with little risk for 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. In order 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 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 (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, Matrix SG (rimsulfuron) and Sandea (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 (pronamide) and Surflan (oryzalin) are 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 (diuron) and Princep (simazine) have relatively low solubility and have been very safe on blueberries. Sinbar (terbacil) has a longer residual life in the soil and also is more soluble, so it should be used infrequently on light, wet soils. Velpar (hexazinone) is very soluble and should not be used on New Jersey sandy 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.
  • Trellis (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.

WSSA group 12 and 27 – Carotenoid Biosynthesis Inhibitors

  • Solicam (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 or Motif (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 (flumioxazin) and Zeus XC or Zeus Prime XC (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 (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 20 – Cellulose Synthesis Inhibitors

  • Casoron (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. So, keep this herbicide ONLY for fall/winter applications. Plants must be at least one year old before Casoron should be used.
Filed Under: Blueberry, Uncategorized Tagged With: , ,
May 26, 2021

Cicadas Are Here and Fruit IPM for 5/26/21

Cicadas are Here, There and Everywhere (Depending where you are): 17 year cicadas began emergence last week. These insects while a marvel in the insect world, are also capable of doing considerable damage to young fruit trees, grape vines, and blueberry bushes. After mating they begin to deposit their eggs in slits along small diameter branches. Thin branches which are loaded with fruit weight and damaged by egg laying can break. Some growers have asked about damage and what they can do to prevent it. Most egg laying is starting this week.

[Read more…]

Filed Under: Blueberry, Fruit, Landscape, Nursery, & Turf, Nursery, Tree Fruit, Wine Grape Tagged With: , , , , , , , , , , , , , ,
March 5, 2021

2021 Recommendations for Residual Weed Control in Established Blueberry

Horseweed

Horseweed / Marestail

With T3 stage scheduled for early April  it’s now time  to consider your residual herbicide application before bud-break!

Residual 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.

Keep also in mind that these herbicides should receive at least ½” rainfall or irrigation one to seven days after application (depending on herbicides) to move the herbicide into the soil

 

 

In order to reduce the potential of selecting for herbicide-resistant weeds, it is highly recommended mixing two residual herbicides with different MOA whenever you apply pre-emergence (residual) herbicides. 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 6 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 a postemergence herbicides to control emerged weeds. Roundup (glyphosate), Rely 280 (glufosinate,) and Gramoxone (paraquat) are postemergence herbicides that may be applied with pre-emergence herbicides before bud break with little risk for crop injury.

  •  MOA 2: Solida (rimsulfuron) and Sandea (halosulfuron) are ALS inhibitors 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
  • MOA 3: Kerb (pronamide) and Surflan (oryzalin) are mitosis inhibitor that will be effective at controlling many annual grass species for 4 to 6 weeks after application. Kerb also help controlling perennial quackgrass. If applied to warm soils (> 55°F), Kerb persistence (and weed control) is much reduced; therefore, reserve Kerb for fall/winter application. Do not use Kerb on blueberries that have not been established for about a year.
  • MOA 5 and 7: The photosynthesis 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 (diuron) and Princep (simazine) have relatively low solubility and have been very safe on blueberries. Sinbar (terbacil) has a longer residual life in the soil and also is more soluble, so it should be used infrequently on light, wet soils. Velpar (hexazinone) is very soluble and should not be used on New Jersey sandy soils. These herbicides are effective on a many broadleaf weed species, including common chickweed, common lambsquarters, common groundsel, henbit, nightshade, redroot pigweed, pineappleweed, shepherd’s-purse, smartweed, and some mustards. Sinbar and Princep will also control most of the annual grasses and help suppressing quackgrass.
  • MOA 12: Solicam (norflurazon) is a pigment inhibitor that may 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.
  • MOA 14: Chateau (flumioxazin), Zeus XC (sulfentrazone), and Zeus Prime XC (sulfentrazone plus carfentrazone) are PPO inhibitors with activity against many broadleaves (including redroot pigweed, catchweed bedstraw, common mallow, common lambsquarters, ladysthumb, wild mustard, and 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. Zeus products may also provide some suppression of yellow nutsedge. Chateau has a 7 day preharvest interval (PHI) and Zeus Prime XC have 3 day PHI, and can therefore be applied later in the season to extend preemergence broadleaves control into late summer. Blueberry plants must have been established at least two years prior to use of these herbicides.
  • MOA 15: Devrinol (napropamide) and Dual Magnum (s-metolachlor) are long chain fatty acid inhibitor. Devrinol 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. Dual Magnum has a 24c Special Local Need label for blueberry in New Jersey. This herbicide controls 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.
  • MOA 20: Casoron (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 dichlobenil formulation), Casoron can lose much of its activity. So, reserve this herbicide ONLY for fall/winter applications. Plants must be at least one year old before Casoron should be used.
  • MOA 21: Trellis SC (isoxaben) is a cell wall synthesis inhibitor currently currently registered for bearing and non-bearing blueberry. Trellis SC primarily controls annual broadleaf weeds, such as horseweed, common lambsquarters, wild mustards, shepherd’s- purse, purslane, and common chickweed; higher rates may also suppress field bindweed and curly dock. However, Trellis SC will have to be mixed with a Group 3, 12, or 15 residual herbicide for controlling annual grasses.
  • MOA 27: Callisto (mesotrione) is an HPPD inhibitor recommended for spring application to 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. Callisto has both preemergence and postemergence activity and can be used in spring prior to bloom to control ALS-resistant horseweed at the rosette stage.
  • MOA 29: Alion (indaziflam) is a cellulose biosynthesis inhibitor recommended for fall or spring application to control annual broadleaf and grassy weeds. Alion has no effect on emerged weeds or established perennials. It should be applied before weeds emerge or tank-mixed with a postemergence (POST) herbicide to control emerged weeds. Do not use Alion on soil classed as sand, or with more than 20% gravel.

Soil-Applied Herbicide Rates (in Active Ingredients) for Common Soil Types

Graph of Soil-Applied Herbicide Rates

N/A = NOT LABELED (DO NOT USE).
1Use the lower recommended rate when tank-mixing with another pre-emergence herbicide, unless annual grass pressure is severe.
2Use one-half the recommended rate when tank-mixing with another pre-emergence herbicide.

The 2021 Commercial Blueberry Pest Control Recommendations for New Jersey will soon be available on https://njaes.rutgers.edu for rates and additional information. The information above is correct to the best of our knowledge. Other formulations with the same active ingredient as some of the products listed above may exist that may or not may be labeled for the same uses. Always consult the label before making pesticide applications. Information was current as of March 5, 2021

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