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

June 30, 2020

Command 3 ME Label Change for Lima Beans

FMC Corporation, Rutgers University and the New jersey Department of Environmental Protection collaborated on labeling Command 3ME for use on lima beans through the release of a 24(c) Special Local Need Label. The label is available online at https://www.cdms.net/ldat/ld324024.pdf.

In the past, the Command 3ME label allowed use in lima beans, but this use was removed a couple of years ago. This new labeling essentially restores the previous use pattern. This labeling only applies to FMC’s brand of Command.

Command 3ME can be applied at 4 to 6 fluid ounces immediately after seeding, with the lower rate recommended for coarse-textured soils. This low rate does not provide control of pigweed species or most broadleaf weeds (including Palmer amaranth), rather it provides early-season weed suppression that allows for improved control with cultivation. This label also allows for planting lima beans 60 days after application in a preceding crop. This allows use for Command use in peas and planting lima beans at least 60 days later.

Currently, Command 3ME received a 24(c) SLN label for use on lima beans only in New Jersey, Delaware, Maryland, and Virginia.

Filed Under: Commercial Ag Updates, Vegetable Crops Tagged With: , ,
June 12, 2020

Carolina redroot control in cranberry with Callisto® herbicide

Figure 1. Carolina redroot infestation in cranberry bog

Carolina redroot (Lachnanthes caroliniana), a native plant of New Jersey Pine Barrens, has becoming an increasingly troublesome weed for cranberry production across the state (Figure 1). Carolina redroot is a perennial herbaceous weed species belonging to the Haemodoraceae family. It competes for nutritional resources during the cranberry growing season, and its rhizome serve as a feeding resource for wintering waterfowl that can cause severe uprooting damages of cranberry vines when bogs are flooded. Carolina redroot blooms after cranberry and its flower is very attractive to pollinators (Figure 2) at a time when insecticides may be applied to cranberry bogs. Additionally, the desiccated seed head of Carolina redroot can be picked up by harvesting equipment and broken in small pieces that will be difficult to eliminate during fruit processing.

Invasive species

Figure 2. Carolina redroot is very attractive for pollinators… at a time when insecticides may be applied!

 

Studies have been conducted at Rutgers since 2017 to screen various herbicides that can properly control or suppress Carolina redroot without injuring cranberry. In greenhouse screenings, Callisto® 4SC (mesotrione) has provided good control of Carolina redroot while maintaining excellent crop safety. Callisto is a systemic herbicide that will cause bleaching of weed leaves by indirectly inhibiting the biosynthesis of carotenoid that protect chlorophyll from photodegradation. Cranberry is highly tolerant because it is capable of rapidly metabolizing the mesotrione. Callisto will not kill Carolina redroot outright, but will weaken it and stunt it, preventing the formation of the floral stem (Figure 3). We are still evaluating if continued annual use of Callisto for two or three years will completely eliminate Carolina redroot.

Bee pollinating flower

Figure 3. Bleaching and stunting of Carolina redroot floral stem following Callisto applied at 4 fl oz/A

Spot application: ideally, Carolina redroot should be controlled before it starts colonizing large areas of a cranberry bogs. Therefore, scouting and mapping is a crucial and necessary step to detect early infestation that be treated with spot application of Callisto. We obtained in 2019 a 24(c) Special Local Need label for spot application of Callisto at rates that will help controlling perennial weeds such as Carolina redroot. We recommend mixing 3.2 teaspoons of Callisto per gallon of water and add crop oil concentrate (COC) at 1% v:v or 2.5 tablespoon per gallon of water. This rate will allow to spray up to 15 gallons of solution per acre while not exceeding the maximum labeled rate of 8 fl oz per acre and per application.

Stunted plant

Figure 4. Reduction of Carolina redroot biomass with spot application of Callisto at three different rates and two different timings of application

At this rate and if Callisto is applied when Carolina redroot emerge above cranberry canopy in early to mid-June, we observed a reduction of Carolina redroot biomass by 70% at the end of the season. Higher rate will not significantly increase Carolina redroot suppression and later application in mid-July will not be effective (Figure 4). Spot applications will be sprayed with a backpack or hand-held sprayer that needs to be properly calibrated. Calibration of hand sprayers is determined by the walking speed of the applicator and the discharge rate from the nozzle along with the concentration of the material in the tank. Use great care in spot-treating. The difference between an 8-oz application and an 80-oz application is only seconds on the trigger. Spot treatments made to runoff will exceed the maximum application rate.

Stunted plant

Figure 5. Annual sedge control with Callisto applied at 4 fl oz/A

Broadcast application: in bogs where Carolina redroot has colonized large areas, chemigation using irrigation sprinklers or boom application should be considered for broadcasting Callisto.  Callisto can be applied at up to 8 fl oz per acre per application, but we observed bleaching and stunting of Carolina redroot floral stem with Callisto at a 4 fl oz/A rate applied with a regular boom. If chemigating, we recommend Callisto to be applied at 8 fl oz/A. Always use a COC adjuvant at 1% v:v. All application should be made when Carolina redoot leaves emerge from cranberry canopy but before the on-start of bloom because COC adjuvant may injure cranberry flowers and reduce pollination. A second application at 8 fl oz/A can eventually be applied after cranberry bloom to help suppressing Carolina redroot. Callisto will also help controlling sedges or rushes (Figure 5). Callisto applications cannot exceed 2 per acre per year and a maximum of 16 fl oz per acre per year.

 

Filed Under: Cranberry Tagged With: , , ,
June 10, 2020

Important Update on Registration of Low-Volatility Dicamba Herbicides

On June 3, 2020, the U.S. Court of Appeals for the Ninth Circuit issued a ruling that vacates current U.S. registrations of of three dicamba herbicides, XtendiMax (Bayer), Engenia (BASF) and FeXapan (Corteva). The Court ruled in favor of a petition challenging the EPA’s 2018 registration decision. The ruling comes after a group of environmental organizations filed a petition with the Court challenging the U.S. Environmental Protection Agency’s . Other dicamba-containing products are not concerned by this ruling.

The subsequent action by the EPA provides, among other things, that “growers and commercial applicators may use existing stocks that were in their possession on June 3, 2020, the effective date of the Court decision. Such use must be consistent with the product’s previously-approved label, and may not continue after July 31, 2020.”

Click here for the EPA’s full order – see page 11 for key details.

The EPA’s order addresses the use, sale, and distribution of existing stocks of  low-volatility dicamba products impacted by the Court’s ruling.

 

 

Filed Under: Commercial Ag Updates, Field, Forage & Livestock, Fruit, Strawberry, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: , , ,
June 1, 2020

Residual Weed Control in Cabbage and Other Cole Crops

Good weed control in transplanted and seeded cole crops requires planning and the use of pretransplant or preemergence herbicide applications.

Cabbage treated pretransplant with Goal and never cultivated.

Cabbage treated pretransplant with Goal.  The crop was never cultivated.

Preplant incorporate Treflan HFP at 1 to 1.5 pt/A for seeded and up to 2 pt/A for transplanted, or apply Dacthal 6F at 6 to 14 pt/A or Prefar 4E at 4 to 9 qt/A preemergence or post-transplant to control annual grasses and certain broadleaf weeds. Choose Dacthal or Prefar in early spring when soils are cold and wet when Treflan may cause temporary stunting. Please make sure to check the label before mixing as these herbicides are registered for use only on certain cole crops.

Goal 2XL and GoalTender 4F are labeled for transplanting ONLY!.  Goal 2XL can ONLY be used pretransplant whereas GoalTender 4F can be used pre-transplant or post-emergence with a 24(c) Special Local Needs label on broccoli, cabbage and cauliflower in New Jersey (NJ 24(c) SLN GoalTender 4F). Build beds, spray, and transplant through the herbicide barrier. Use Prefar or Dacthal post-transplant for grass control. Treflan or Dual Magnum applied preplant incorporated may increase the risk Goal injury. Do NOT cultivate unless weeds appear. Incorporation of Goal reduces or eliminates the effectiveness of the product for weed control. Goal and GoalTender are registered for use only on certain transplanted cole crops.

Dual Magnum 7.62E has a 24 (c) Special Local Needs label for use on cabbage in New Jersey. Use Dual Magnum at the rate of 0.5 to 1.33 pt/A  depending on soil type. Use the lower rate on soils that are relatively coarse-textured or low in organic matter; use the higher rate on soils that are relatively fine-textured or high in organic matter. Apply to weed free soil in transplanted cabbage after transplanting, or to direct seeded cabbage when the seedlings have developed 3 to 4 true leaves. The delayed use in directed seeded cabbage reduces the risk of slight temporary stunting of the crop. Dual Magnum controls annual grasses, nightshade species, and galinsoga. Yellow nutsedge will be suppressed or controlled at the rates and use patterns on the Dual Magnum label for cabbage. To obtain a label, an indemnification agreement must be filled out on line agreeing not to hold the manufacturer responsible for crop damage. Obtain a copy of the label and complete the indemnification agreement on the Syngenta website. Register or sign in, select state and product, and submit. You will then be asked to select your crop before accepting or not the waiver of liability and indemnification agreement. You must have a copy of this 24(c) label if you want to use Dual Magnum on cabbage!

Consult the 2020/2001 Mid-Atlantic Commercial Vegetable Production Recommendations for rates and additional information.

 

Filed Under: Vegetable Crops Tagged With: , , , ,
May 30, 2020

Specialty Crops Injury Caused by Dicamba Herbicide Drift

Figure 1. Non-tolerant soybean foliage when exposed to a sublethal rate of dicamba 2 weeks after treatment. Leaves are cupped with the bottom edges curved towards the top surface of the leaves.

By Maggie Wasacz1 and Thierry Besancon2

1 Rutgers Weed Science Graduate Student; 2 Rutgers Weed Science Extension Specialist for Specialty Crops

Glyphosate-tolerant soybeans were first commercialized in 1996 in the United States. By 2006, almost 9 out of every 10 soybean acres were planted with glyphosate-tolerant cultivars. However, reliance on glyphosate alone for soybean weed control stimulates the selection of weed biotypes naturally resistant to glyphosate. By 2019, there were 43 weed species known to be resistant to glyphosate, including species such as Palmer amaranth or waterhemp that can easily out-compete soybean and reduce yield by more than 50% if left uncontrolled.

What is Dicamba Herbicide?

One way to control glyphosate-resistant weeds is to treat them with herbicides other than glyphosate, such as dicamba. Dicamba is a synthetic auxin herbicide that has been used to control broadleaf weeds for over 50 years. Chemical and seed companies have recently developed new soybean varieties that are tolerant to dicamba and that started to be commercialized in 2016. With the development of genetically modified dicamba-tolerant soybeans, dicamba may be sprayed more frequently during the growing season. Additionally, dicamba is regularly applied in corn, for right-of-way applications, and in the early fall for perennial weeds control.

Dicamba can injure sensitive broadleaf plants through tank incorrectly rinsed after spraying dicamba, particle drift during the dicamba application, and vaporization after dicamba has been applied . Particle drift refers to the herbicide being carried off-target by the wind during the application. Wind speed, particle droplet size, nozzle type, carrier volume, application method, and application speed will affect the extent of particle drift. Vaporization, on the other hand, occurs when the herbicide evaporates from the target plant and these vapors travel off-target.  For more information on herbicide drift, please refer to the following PPA post 10-best-management-practices-to-avoid-herbicide-drift.

If some of the dicamba sprayed onto a soybean field moves off-target and lands on a nearby field planted with a sensitive crop, the results can be very harmful. This injury could potentially cause aesthetic damage as well as reduce yield reduction.  Potential for yield loss is influenced by amount of dicamba as well as when the injury occurs. Small volumes of dicamba products can cause leaf cupping and deformation, plant twisting, and in extreme cases, plant death of sensitive crops.

Screening Vegetables for Dicamba Sensitivity

Greenhouse studies conducted at Rutgers University in 2019-2020 screened economically important vegetable crops from the mid-Atlantic region for sensitivity to sublethal doses of dicamba. These micro-rates of dicamba simulated varying levels of drift conditions in the field. To put the rates into perspective, the highest dose in this study was equivalent to about one drop of product per quart of water. The goals of this study are to develop recommendations that can help growers design their planting strategies around dicamba-treated fields as well as to use this data to help refine recommendations to maximize protection of sensitive crops.

Crop-Specific Reactions to Simulated Dicamba Drift

The most sensitive crops in this study were the leguminous crops, including non-tolerant soybean, lima bean, and snap bean, as well as solanaceous crops, such as tomato, eggplant and pepper. These crops demonstrated severe injury.

Soybean injury is characterized by the underside edges of the leaves curling upward toward the top surface of the leaves (Figure 1). Lima bean and snap bean have similar injury symptoms, both exhibiting injury in several ways. Higher rates caused some leaves to not emerge at all, while lower rates caused leaf cupping injury that caused the top edges of the leaves to curve downward towards the ground. Other symptoms included a bubble-like texture on the top sides of the leaves, as well as leaf crinkling.

Figure 2. Eggplant 2 weeks after treatment. The undersides of affected leaves are curled upward toward the top surfaces of the leaves.

Figure 3. Bell pepper 2 weeks after treatment. The leaves are cupped with a bubble-like texture on the top surface.

 

 

 

 

 

 

Figure 4. Tomato 2 weeks after treatment. Leaflets are curled, reduced in size, and deformed.

For eggplant and bell pepper, injury was expressed as the undersides of the leaves curling upward toward the top surface (Figures 2 and 3). Additionally, leaf crinkling is seen in bell pepper foliage (Figure 3). Finally, tomato plants express dicamba injury with leaf twisting, cupping, stunting, and crinkling. At higher rates, these leaflets will be extremely stunted and deformed (Figure 4). Lower rates will show slight cupping, leaf crinkling and a change in leaf surface texture. Among the most tolerant crops from this study were basil, pumpkin, lettuce, and kale. These plants incurred the lowest amount of damage. The moderately sensitive crops included watermelon, cucumber, and summer squash. Watermelon foliage exhibits injury differently than many of the other crops tested in the study. Rather than leaf cupping, watermelon leaf texture appears shriveled and more deeply lobed with small bubbles on the top leaf surface (Figure 5).

 

 

Figure 5. Watermelon 2 weeks after treatment. Leaves are deeply lobed with a puckering, bubble-like texture.

Figure 6. Summer squash 2 weeks after treatment. Leaf edges are curved downward toward the ground.

Figure 7. Cucumber 2 weeks after treatment. Leaf is cupped and the bottom edges of the leaf are curved upward towards the top leaf surface.

 

Summer squash and cucumber, however, show leaf cupping when injured. In summer squash, the top edges of the leaf curve downward towards the ground (Figure 6).  The foliage of cucumber tends to curve the bottom edges upward toward the top surface of the leaf, although both directions of cupping were observed. (Figure 7).

On-Going Research at Rutgers

This summer, Rutgers researchers will select a few of these crops to take yield in a field-based dicamba drift study that tests different drift rates and application timings. Although this study gives some preliminary information, more detailed studies are necessary to confirm these findings. However, in the meantime, this greenhouse work gives us a brief snapshot of which species to be most concerned with when working near dicamba treated fields and provides help with field identification of these injury symptoms.

If you suspect that dicamba drift may have injured your crops, please contact you local county extension agent or Rutgers weed science specialist (Dr. Thierry Besançon) as soon as possible, and take detailed pictures of the observed damages.

 

 

Filed Under: Blueberry, Commercial Ag Updates, Fruit, Organic Production, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: , , , , , ,
May 22, 2020

10 Best Management Practices to Avoid Herbicide Drift 

The last few weeks have been very windy, and we already received numerous calls from specialty crops growers inquiring about the risk of herbicide drift or investigating if observed crop damages may be the result of herbicide drift.

Blueberry flowers

Fig.1 Paraquat drift on blueberry flowers

Why does it seem like crops are more affected by herbicide drift in the spring? Well, mostly because this is the time when newly planted crops develop new shoots or reproductive structures that may be very sensitive to herbicide drift (Figure 1). This is also the time of the year when most postemergence herbicide are applied to control emerged weeds and subsequent new flushes. When both events coincide and if weather conditions favor herbicide drift, this could lead to disastrous injury on sensitive non target crops!

Drift is defined as physical movement of an herbicide through air, at the time of application or soon thereafter, to any site other than that intended. It can be particle drift from fine herbicide spray droplets that can travel over long distances during period of high wind. High wind speed, low relative humidity, high temperatures, small droplet size, and spray boom maintained high above the ground are factors that increase the risk of particle drift. Depending on the herbicide, application and weather conditions, fine droplets can travel up to several miles! It can also be vapor drift which results from the ability of an herbicide to vaporize and mix freely with air. Volatility of any herbicidal substance is characterized by its vapor pressure. The higher the vapor pressure of a substance, the greater its tendency to volatilize (Table 1). However, other factors such as herbicide formulation and weather conditions will influence volatility. Some herbicides classified as growth regulators (2,4-D, dicamba, triclopyr or clopyralid) are well known for the higher risk of vapor drift associated with their use when herbicide formulation and/or weather conditions increase volatility (Figure 3).

Herbicide Vapor Pressure (mmHg)
Glyphosate IPA 1.58 x 10-8
Glyphosate Ammonium Salt 6.75 x 10-8
2,4-D DMA <1.0 x 10-7
2,4-D Acid 1.4 x 10-7
Atrazine 2.9 x 10-7
2,4-D BEE 2.4 x 10-6
2,4-D EHE 3.6 x 10-6
Trifluralin 1.1 x 10-4
Clomazone 1.4 x 10-4
Table 1 Vapor Pressures for 2,4-D Formulations and Several Commonly Used Herbicides. Abbreviations: IPA, isopropylamine; DMA, dimethylamine; BEE, butoxyethyl ester; EHE, 2-ethylhexyl ester.

So, there are a few things that you need to consider reducing the risk of potentially expansive damages to sensitive crops:

  1. Select nonvolatile or low volatility herbicides to minimize the risk of vapor drift. Growth regulator herbicides such as 2,4-D, MCPA or triclopyr can be formulated as ester or amine salt. The ester formulation is notorious for its volatility; therefore, always use these herbicides formulated as amine salt to reduce the risk of vapor drift. Other herbicides than growth regulators have high vapor pressure that makes them prone to vapor drift (clomazone, trifluralin, EPTC), but either should be soil incorporated or are formulated in a way (micro-encapsulation) that will limit the risk of vapor drift.

    Beet plant

    Fig. 2 New growth chlorosis on beet. A WSSA group 27 herbicide (“bleacher”) was applied preemergence at planting in a neighboring corn field and drifted to the beet field because of high wind.

  2. Carefully read the herbicide label. The product label will provide information regarding when it is not safe to apply the product based on various parameters such as wind speed, temperature, humidity. You may also find information buffer requirement when spraying near sensitive downwind plants or information on the type of nozzle you must use for a specific herbicide.
  3. Select nozzles that produce the large size droplets while providing adequate coverage at the intended application rate and pressure. You can also select specifically designed drift-reduction nozzles (for example, drift-guard or air induction types) operate at lower pressure (15 to 30 psi) and produce large droplets that will have less potential for drift. A good source of information on droplet characteristics and operating pressure for various nozzle types is the TeeJet nozzle catalog (https://www.teejet.com/CMSImages/TEEJET/documents/catalogs/cat51a_us.pdf).
  4. Use low application pressure and drive at low speed when applying herbicides. Herbicide drift will increase with application pressure and speed…
  5. Keep the boom stable and the nozzles close to the soil as this will minimize herbicide drift but also potential injury to the crop on which herbicide is applied. You may want to consider using a shielded boom when spraying herbicide that are prone to drift or may injure your crop. Keep in mind that postemergence herbicide will provide optimal weed control when applied timely with regards to weed development. If the weeds are too tall (see the maximum weed size for each weed species on the label), then it’s too late to spray!

    Damaged crops

    Fig. 3 Damages to pepper (left), cucumber (center), and eggplant (right) caused by dicamba herbicide applied at 1/1000 of the labeled rate on soybean.

  6. Mix spray additives recommended by the label to reduce the production of fine spray droplets. Avoid tank mix ammonium sulfate with volatile herbicides as ammonium sulfate increases volatility. You can also consider the use of drift retardants that reduce drift by increasing the viscosity or surface tension of a spray solution. However, research shows that while some drift retardants may help under some conditions, the prevention of herbicide drift should primarily rely on nozzle selection, boom height, application pressure, and environmental conditions.
  7. Do not apply herbicides when wind is blowing toward sensitive plants or when wind speed exceeds 10 mph. Ideal spray conditions are when wind speed is between 3 and 10 mph. Low winds (< 3 mph) tend to be unpredictable and variable in direction and may indicate conditions that help the development of a temperature inversion. Applying any herbicide when wind speed exceeds 10 mph may result in catastrophic consequences for neighboring sensitive vegetable or horticultural crops (Figure 2).
  8. Do not apply herbicides when temperature inversion occurs. Inversions occur when warm light air rises upward into the atmosphere and heavy cool air settles near the ground, preventing the mixing of air layers. Temperature inversion will cause small-suspended droplets to form a concentrated cloud that can move long distances (up to several miles). Typically, temperature inversions start at dusk and break up with the sunrise because of vertical air mixing. To confirm the presence of an inversion, air temperature should be measured carefully at two heights out of the direct sun: 6 to 12 inches above the ground or the top of a nearly closed-crop canopy, and at a height of 8 to10 feet above the surface to be sprayed. When the temperature at the higher level is greater than the temperature at the lower level, an inversion exists. The greater the temperature difference between the two levels, the more intense the inversion, and the more stable the lower atmosphere. To test for sure, you can use smoke by burning a small amount of dry vegetation to see if the smoke dissipates or hangs low to the ground. If the smoke hangs in the air together then moves off slowly without dissipating, it indicates that a temperature inversion exists and that you do not want to spray as  long as the temperature inversion persists. Usually, temperature inversion will dissipate when temperature rises 3 degrees or more above the morning low, or when the wind speed increases to more than 3 mph.
  9. Spray when temperatures remain below 80°F to minimize vaporization and droplet evaporation. This will minimize vapor drift but also help with weed control by avoiding that spray droplets evaporate before reaching the target…
  10. Leave a buffer zone between treated fields and sensitive plants. Herbicide labels may specify the width of the buffer zone. The buffer zone will allow larger droplets to settle before reaching sensitive plants. The buffer zone may not be effective in settling small droplets.

Remember that all herbicides are capable of drift, no exception.

When spraying a pesticide, you have a moral and legal responsibility to prevent it from drifting and contaminating or damaging neighboring crops and sensitive areas. Always monitor weather conditions and their evolution carefully when spraying an herbicide. Overall, do not spray if all conditions are not suitable, and stop spraying if conditions change and become unsuitable.

Filed Under: Blueberry, Cranberry, Field, Forage & Livestock, Fruit, Landscape, Nursery, & Turf, Nursery, Strawberry, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: ,