Thierry Besancon

April 20, 2020 Thierry Besancon

Safely Using Herbicides in Re-Used Plastic Mulch

Plastic mulch and trickle irrigation are expensive. Re-using the mulch for a second crop after the first can be an effective way to spread the cost.

Plastic mulch and trickle irrigation are expensive. Re-using the mulch for a second crop after the first can be an effective way to spread the cost. When the cost of supplies and labor are evaluated, re-using a field with trickle irrigation and black plastic mulch is an attractive idea, but weed control can be a problem.

The herbicides used under the plastic and between the rows of mulch for the first crop must be safe and labeled for use in the second crop. Prefar applied at 6 quarts per acre in a band when the mulch is laid is a good choice for under the plastic. Prefar is labeled for many vegetable crops but ALWAYS check the label to see if the crop you plan to plant is listed on it. Prefar and Gramoxone plus NIS (nonionic surfactant), applied as a shielded banded spray between the rows of mulch, are also labeled for a wide range of vegetable crops. Be sure post plant applications of Gramoxone plus NIS are shielded, applied at low pressure, and a low drift agent is used.

Often the greatest challenge is eliminating the first crop and any weeds in the field prior to planting the second crop in the mulch. No herbicide should be sprayed broadcast over the mulch except Gramoxone, which is quickly broken down by sunlight.

Roundup and other glyphosate products should NEVER be used on plastic mulch. Gyphosate has no residual activity due to strong and immediate adsorption by the soil where it is slowly broken down by soil microorganisms as a food source. On plastic mulch without contact with the soil, glyphosate does not easily wash off the plastic with rain or irrigation. The simple act of letting the root ball in contact with the plastic during transplanting can expose the crops roots to enough glyphosate to cause lasting injury and crop loss!

Residual herbicides must be banded between the rows of plastic mulch, NEVER sprayed broadcast over the mulch. Broadcasting residual herbicides over plastic mulch can increase the risk of washing the herbicide from the plastic into the planting hole when it rains or if you irrigate overhead. Herbicide concentration in the planting hole will be way higher than the safety threshold for any crop! If the herbicide from 1 square foot of plastic washes into the 3 square inch planting hole, that will increase increase 48 times the intended herbicide rate in the planting hole!!! You can certainly not expect good crop safety from any herbicide at 48 times the intended rate! Keep all residual herbicides off the plastic mulch.

In summary, the greatest weed control challenge in re-used plastic is weeds growing under and through holes in the mulch. Gramoxone is broken down by sunlight, so it can be used to kill the first crop and emerged weeds. Consider fumigating under the mulch with a water soluble fumigant injected through the trickle irrigation to provide weed control in the second crop. Disease control may be another added benefit. Remember to wait until the fumigant has dissipated before planting.

Filed Under: Vegetable Crops Tagged With: herbicide, peppers, tomato, weed control

March 31, 2020 Thierry Besancon

Where Can I Find the 24(c) Label for Dual Magnum Herbicide in Highbush Blueberry

I’ve been recently asked by a few people if Dual Magnum is really labeled for use on highbush blueberry since they cannot find the label on the CDMS website. Dual Magnum received a 24(c) Special Local Need label for various crops in New Jersey, including highbush blueberry.

The 24(c) label is an indemnified label provided by Syngenta, meaning that this label con only be distributed to users that have agreed in writing to the terms and conditions of the use including a waiver of liability.

Therefore, the label is only available from the Syngenta website: https://www.syngenta-us.com/labels/indemnified-label-login

You’ll have to create an account before being able to login to the website. Once you have logged in, you’ll be redirected to the Indemnified Label Search page where you need to enter the information for State (New Jersey) and Product (Dual Magnum, and select “Blueberries, Highbush” for use on. You’ll then have to read the Waiver of Liability and Indemnification Agreementbefore deciding to accept or decline it. If you accept the Waiver, you’ll be redirected to the actual Dual Magnum 24(c) label for use on highbush blueberry.

Filed Under: Blueberry

March 16, 2020 Thierry Besancon

2020 Recommendations for Preemergence Weed Control in Established Blueberry

With T3 stage scheduled for late March, it’s really time now to apply your preemergence herbicides before blueberry bud break!

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. 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 incorporate the herbicide in 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 preemergence 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 preemergence 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 therefore be used in spring to control ALS-resistant horseweed at the rosette stage.

Consult the 2020 Commercial Blueberry Pest Control Recommendations for New Jersey 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 February 25, 2020.

Filed Under: Blueberry, Uncategorized Tagged With: blueberry, herbicide, weed control

November 15, 2019 Thierry Besancon

Considerations for Fall Weed Control in Vineyards

Fall or early winter is the best time to consider the application of a residual herbicide that will help maintaining the ground clean in early spring and allow for delayed herbicide applications in spring. Most residual herbicides primarily control annual grasses or annual broadleaf weeds. A combination of an annual grass herbicide and an annual broadleaf weed herbicide is usually recommended. Rate ranges are recommended for most residual herbicides. Use the lower rates in vineyards with coarse textured (sandy) soil low in organic matter, and the higher rate when soils are fine textured (silt and clay) and have higher organic matter.

Post-harvest application of a residual herbicide should be done in late fall after vines are dormant, but before the soil freezes, or in late winter before the weeds begin to grow in early spring. This application targets the control of winter annuals and provides early season control of summer annual weeds. Most growers are more easily able to apply herbicides to the vineyard in late fall, usually after Thanksgiving in New Jersey. In March, growers find themselves scrambling to apply insecticides and fungicides, and prune.

Pruned wood must be removed or chopped before weed spraying can be accomplished. Weed residues from last season should also be removed as much as possible before considering application of a residual herbicide in fall. Too many leftover residues will prevent the residual herbicide to penetrate into the soil (the “activation” process), and the herbicide will lose efficacy at controlling the emergence of weed seedlings. If you plan hilling-up the vine, be aware that the de-hilling operations will break the residual herbicide coverage. Thus, hilling may not compatible with the use of residual herbicide in fall.

Casoron (dichlobenil), applied in late fall, followed by a spring application of a residual annual grass herbicide is a very effective residual weed control program. More different species of weeds are controlled than any other residual herbicide combination available. Apply 4.0 lb active ingredient Casoron CS (2.7 gallons per acre) or 4.0 to 6.0 lb active ingredient Casoron 4G (100 to 150 lb per acre) in late fall when soil and air temperatures will remain below 50 degrees Fahrenheit until rainfall moves the herbicide into the soil. The active ingredient in the granular formulation can be lost to volatilization in warm weather. The Casoron CS formulation is encapsulated, which prevents loss due to volatilization. Casoron provides annual broadleaf weed control through harvest and annual grass control until early summer the next year. Certain herbaceous perennials, including goldenrod species, aster species, and yellow nutsedge will also be controlled or suppressed by Casoron applied in late fall. Late winter applications provide less consistent winter annual and perennial weed control. Apply an additional residual annual grass herbicide in the spring to provide late summer annual grass control following the late fall application of Casoron.
For many years Princep (simazine) was recommended at 1.0 to 2.0 lb active ingredient per acre in the late fall/ winter, and Karmex (diuron) was recommended at 1.0 to 2.0 lb active ingredient per acre in the late spring. Both herbicides have been safe and reliable, and cost effective choices for many years, and continue to be good options where their use provides good weed control. Both Princep (simazine) and Karmex (diuron) share the same mode of action, inhibition of the light reaction in photosynthesis. Unfortunately, triazine resistant weeds, with cross resistance to urea herbicides, including Karmex, are present at some sites. Where a triazine resistant weed has become established, switch to herbicide(s) a different herbicide mode of action. Use Chateau or Tuscany (flumioxazin) at 0.19 to 0.38 lb of active ingredient per acre or Goal 2XL (oxyfluorfen) at 1.0 to 2.0 lb of active ingredient per acre in late fall or late winter. The activity of both Chateau and Goal occurs at the soil surface as sensitive BLW seedlings emerge. Do not disk, till or otherwise mechanically mix Chateau or Goal into the soil after application, or the effectiveness of the herbicides will be reduced or eliminated.
Alion (indaziflam) is a relatively new (2012) herbicide labeled for use in stone and pome fruit orchards, and in vineyards. Alion is very effective at controlling a broad range of annual grasses and broadleaf weeds. Alion does not provide control of sedges or established perennial weeds. Alion is ideally applied in late fall at 0.045 to 0.065lb of active ingredient per acre in late fall. The most compelling characteristic of Alion is its VERY long weed control period (up to 6 months). However, the use restrictions for Alion are stricter in vineyards than in orchards:

1. Alion can only be applied in vigorous grapes that have been established for a minimum of three years after transplanting.
2. Alion can only be used in grapes that have at least 6 inches of soil barrier between the soil surface and the major portion of the root system.
3. Alion cannot be used on soils with 20% or more gravel content or on sand or loamy-sand soil.
4. Do not apply Alion prior to any type of soil disturbance, including hilling/dehilling operations, and only apply the herbicide after the soil settles.
5. Do not allow spray or spray drift to contact crop foliage, green bark, roots or fruit of the crop being treated as it may cause localized crop injury or death
6. Maximum use rate per application now has a restriction based on soil organic matter (OM) content: if soil contains less than 1% OM, maximum rate is 3.5 oz/A (0.045 lb ai) and if over 1% maximum rate is 5 oz/A (0.065 lb ai). In any case, maximum use rate cannot exceed 5 oz/A (0.065 lb ai) per year or in a 12 month period.
7. No irrigation can be applied within 48 hours following Allion application. This is designed to ensure crop safety by giving the herbicide enough time to bind to surface soils before rainfall or irrigation to ensure proper activation of Alion by allowing weed seeds or seedlings to come into contact with the herbicide.

The Alion label also lists some guidelines that will ensure efficient weed control:

Soil should be free of debris, clumps or cracks at application time to ensure best weed control performance and prevent the herbicide from reaching the grape roots (this is true for best performance of ANY of our PRE herbicides).
For best weed control, dry soil surface for 48 hours followed by rainfall or sprinkler irrigation within 3 weeks is ideal. If irrigation is used to activate, 0.5 inch of water is ideal (the idea is to incorporate the herbicide into the surface an inch or so, where the weeds germinate, but not go too deeply. This is also true for all PRE herbicides.

Consult the New Jersey Commercial Blueberry Pest Control Recommendations for rates and additional information https://njaes.rutgers.edu/pubs/publication.php?pid=E283.

As with all herbicides,always read and follow all label instructions and precautions.

Filed Under: Wine Grape

October 10, 2019 Thierry Besancon

Gramoxone/paraquat Mandatory Training Required Before Use

Spraying for pests

All pesticide certified applicators must successfully complete an EPA-approved training program before mixing, loading, and/or applying paraquat.

Anyone using Gramoxone, Firestorm, Helmquat, Parazone, and other paraquat products must complete an EPA-mandated training before application.

After November 14, 2019, the EPA requires companies to have newly labeled products on the market.

The following are items related to the new label for paraquat products:

Only certified applicators, who successfully completed the paraquat-specific training, can mix, load or apply paraquat.
No longer allow application “under the direct supervision” of a certified applicator.
Restricting the use of all paraquat products to certified applicators only.
EPA required Online Training – users must create an account with username and password.
A certificate will be delivered by the end of the training after successful completion of the online exam.
Applicators must repeat training every three years.

For additional information and FAQs about the paraquat training go to the EPA Paraquat Training website

Filed Under: Blueberry, Commercial Ag Updates, Fruit, Landscape, Nursery, & Turf, Organic Production, Tree Fruit, Turf, Vegetable Crops, Wine Grape

September 12, 2019 Thierry Besancon

Annual Bluegrass Control in Blueberry

Annual bluegrass (Poa annua L.) is an increasingly troublesome winter annual weed in some New Jersey blueberry fields. Native to Europe, this species is now worldwide distributed.

Identification and Life Cycle

Figure 1. Annual bluegrass. Thierry Besancon, Rutgers University

Annual bluegrass starts germinating in late summer as soil temperature drops below 70°F. If conditions are favorable, it will continue germinating throughout the winter. Annual bluegrass has light green leaves with a typical boat-shaped tip (Figures 1 and 2). Leaf blades are often crinkled part way down. It will produce greenish white inflorescences (seed heads) during the spring months. Annual bluegrass is a prolific and rapid seed-producing weed.

Each plant can produce up to 100 seeds that are viable just a few days after pollination, allowing multiple germination flushes during the cool season. Annual bluegrass tends to form dense clumps in areas with moist and/or compacted soil. Poor soil drainage, frequent irrigation, excessive fertilization, use of heavy equipment causing compaction, and shade are conditions that will encourage the development of annual bluegrass.

Figure 2. Annual bluegrass leaf tip. Joseph M. DiTomaso, University of California – Davis, Bugwood.org

Impact

While annual bluegrass may not be a strong competitor for blueberry bushes, it forms a dense mat that will persist until late spring. This mat will prevent proper application of residual herbicides in spring by intercepting the spray solution and reducing the amount of residual herbicide penetrating into the soil. Thus, control of established sod of annual bluegrass prior to spring herbicide applications is essential for successful residual weed control in spring and early summer.

Management

As for any other weed species, preventing the release of viable seeds that will replenish the soil seedbank is a primary objective for controlling this species. Cultivation or manual digging before annual bluegrass patches become well established and before the development of inflorescence will provide control of limited infestations if continued throughout the germination period. However, the use of chemical control may be required for large infested areas or where the species has become established for several seasons.

Application of effective preemergence herbicides may prevent annual bluegrass seedling survival. However, preemergence herbicides will not effectively control emerged plants. Timely application of preemergence herbicides is very important for effective control of annual bluegrass. Herbicides should ideally be applied in late-summer / early fall before annual bluegrass seeds germinate. However, crop injury may result if pre-emergence herbicides are applied at this time when blueberry bushes are not dormant. Therefore, a fall application of a preemergence herbicide tankmixed with a postemergence herbicide is often the most practical solution and should be considered when blueberry leaves start dropping.

Preemergence herbicides such as oryzalin (Surflan), norflurazon (Solicam), or napropamide (Devrinol) may effectively control annual bluegrass. Application of these herbicides can be split between fall and spring applications with half of the yearly rate applied in fall and the second half in spring.
Simazine (Princep) can provide early post-emergence control of leaf stage plants in addition to its residual activity.
Pronamide (Kerb SC) is also an excellent option that will provide both residual and postemergence control of annual bluegrass. Optimum pronamide activity occurs when applications are made under cool temperature conditions (55°°F or less).
S-metolachlor (Dual Magnum) is also effective at controlling annual bluegrass prior to germination. However, Dual Magnum can only be applied once per cropping season and will require grower to agree to the conditions of the indemnified label (https://www.syngenta-us.com/labels/indemnified-label-search).

All preemergence herbicides require incorporation from rainfall so that the herbicide can move into the first few inches of soil where it will be protected from degradation or volatility.

When annual bluegrass has emerged before residual herbicide is applied, a postemergence herbicide should be included in the tank. Use paraquat (Gramoxone or other labeled generic formulation) plus a nonionic surfactant at 0.25% v/v of the spray solution. Glufosinate (Rely 280) is also effective at controlling emerged annual bluegrass, especially when applied under bright sunlight, warm temperature, and high humidity conditions. Do not allow glufosinate spray mist to contact green bark, as injury will occur. None of the graminicides labelled on blueberry (Select, Poast) have sufficient activity for controlling annual bluegrass. The use of glyphosate (Roundup or other labeled generic formulation) is not recommended as failure to control emerged annual bluegrass has been reported in various New Jersey blueberry fields.

Consult the New Jersey Commercial Blueberry Pest Control Recommendations for rates and additional information (https://njaes.rutgers.edu/pubs/publication.php?pid=E265). As with all herbicides, read and follow all label instructions and precautions.

Filed Under: Blueberry, Uncategorized