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

August 30, 2018

Fall control of perennial weeds with herbicides

Late summer and fall are perfect times to work on tough-to-control perennial weeds such as Virginia creeper vine, bindweed, green-brier, Canada thistle, goldenrod, and poison ivy. These perennials are among the most difficult weeds to eradicate, especially because of their ability to generate new shoots from their root systems. Successful management strategies will mostly rely on herbicide that can move from the leaf to the below-ground plant parts. Timely initial application and consistency at controlling any regrowth with follow-up spot treatments are crucial for long-term control of these weeds.

3 different species of weeds that affect blueberries

Field bindweed (upper left), goldenrod (lower left) and green-brier (right) are some tough weed species of NJ blueberry and will warrant extra time for achieving successful control

Glyphosate (Roundup or other generic products) is the only postemergence herbicide labeled on blueberry that can provide good control of perennial weeds. Late summer and fall are good times for applying glyphosate as plant sap movement is mostly directed toward the roots where nutrients will be stored in anticipation of next season. Therefore, large volume of glyphosate can easily be translocated from the leaves to the roots, improving the efficiency of the herbicide at killing below-ground storage organs. It is VERY IMPORTANT for glyphosate to be applied when weed leaves are still green before fall colors appear.

Use extreme care not to contact crop green tissues (stems and leaves) with glyphosate. Glyphosate absorbed by crop green leaves and bark moves within the plant and can severely damage or kill above-ground and below-ground parts of annual crop and perennial treess. Weeds such as bindweed, Virginia creeper, and greenbrier may need to be pulled out of the trees so they can be treated safely. This may seem too slow to be practical, but consider what these weeds cost in lost income. For example, blueberry bushes covered by Virginia creeper vine may yield just 20% of their potential. This easily equates to a $5 to $10 loss per bush. The loss is incurred each year and increases as the vines spread to neighboring bushes. Investing 15 minutes to carefully pull vines out of that bush and safely treat them on the ground is money well spent.

Glyphosate should be applied through low pressure spot treatment to limit drift movements. Glyphosate absorption will be improved if ammonium sulfate (17 lbs / 100 gal water) is added to your spray mixture. For effective control, at least 50% of the foliage should be wet with glyphosate applied as a 2% solution (see your product’s label for rate necessary to reach this concentration).

Consider also “cut stump” applications for Virginia creeper or poison ivy that have large diameter stems. Apply a 2% glyphosate solution to the cambium (inner bark area) IMMEDIATELY after cutting the stem. Don’t let time for cutting to dry as this would prevent glyphosate absorption and translocation to below-ground plant parts.

Always apply glyphosate on weeds that are actively growing and not under drought stress.

Always refer to the commercial product label for rates and additional information.

Filed Under: Blueberry, Cranberry, Fruit, Tree Fruit, Vegetable Crops, Wine Grape
May 18, 2018

24(c) Special Local Need label for spot treatment with Callisto in cranberry

Callisto® (mesotrione) is a systemic preemergence and postemergence herbicide. It works mainly on broadleaf weeds and sedges, and does not work well against most of grasses. When used preemergence, weeds take up the product through the soil during emergence. When used postemergence, weeds absorb the herbicide through the treated foliage and also through the soil.Plants affected by Callisto® will turn white. Injury may take several days or weeks to show.

Callisto® recently received a New Jersey 24(c) Special Local Need label for spot treatment of tough-to-control weeds in cranberry. This type of application will concentrate the herbicide on a localized area of the bog, allowing a higher use rate that can provide control of dodder, dewberry, Poison ivy, or smilax.

The addition of a crop oil concentrate (COC) type adjuvant at 1% v/v or a nonionic surfactant (NIS) type adjuvant at a rate of 0.25% v/v is recommended for improved control of emerged weeds.

 
  Callisto® Herbicide /Gallon
 Maximum Solution per Acre per Application Solution Description
0.8 teaspoon
30 to 60 gal
approximates 4 oz/acre rate
1.6 teaspoons 30 gal
approximates 8
oz/acre rate
3 tablespoons
 5.3 gal
very concentrated, for woody weeds

 

There are a number of restrictions associated with this 24(c) SLN label:

  • Callisto® may be applied in cranberries at a rate up to 8 fl oz/A and not more than 16 fl oz/A in total per year.
  • Callisto® applications cannot exceed 2 per acre per year.
  • If two applications are made, they must be made no closer than 14 days apart.
  • In non-bearing cranberries, make the Callisto® application(s) after the bud break stage, but not less than 45 days before flooding in fall or winter.
  • In bearing cranberries, make the Callisto® application(s) after the bud break stage, but not less than 45 days prior to flooding or harvest.
  • DO NOT apply directly to water or areas where surface water is present outside the bog system.
  • DO NOT contaminate water when disposing of equipment wash water or rinsate.
  • DO NOT apply within 10 feet of surface water outside the bog system.
  • Do not apply when weather conditions may cause drift to non-target areas. Drift may result in injury to adjacent crops and vegetation. To avoid spray drift, DO NOT apply when wind speed is greater than 10 mph or during periods of temperature inversions. Use of larger droplet sizes will also reduce spray drift.

The new 24(c) SLN label is available at this address http://www.cdms.net/ldat/ld56N003.pdf

Filed Under: Cranberry
April 18, 2018

Matrix SG Supplemental Label for Highbush Blueberry

The U.S. Environmental Protection Agency (EPA) a Section 3 Supplemental Label for use of the herbicide Matrix SG 25% WDG (rimsulfuron) for use on blueberries, raspberries and blackberries. This label will be in effect through March 31, 2020.

Matrix may be applied to these crops at 4 oz product per acre. It may be applied pre-emergence or early post-emergence to the weeds. If weeds are present at application, add non-ionic surfactant at 0.25%to the tank mix. Matrix is most effective if moved into the soil (activated) by 0.5-inch rainfall.

On highbush blueberries, apply Matrix to bushes established at least one year. Apply in a strip on each side of the row, avoiding contact with green blueberry leaves or stems. Matrix is moderately soluble and should not be used on soils classified as sands to avoid leaching into the bush root zone. Do not exceed 4 ounces product per acre per year. If Matrix is applied in a band of 50 percent or less of the total area, a second application may be made each year. Matrix may be applied up to 21 days before harvest.

Matrix herbicide is active against several annual grasses and broadleaves, including mustards and pigweeds. It has fair activity against most of the composites, but is weak on common groundsel. It is also weak on common lambsquarters and eastern black nightshade. It will provide six to eight weeks of weed suppression at the labeled rate, and is most effective if used with other residual herbicides. Matrix will also provide suppression of yellow nutsedge. To obtain the most effective results, use the highest rate allowed based on the width of your spray band and make two applications. Make the first application when emerging nutsedge is 2 to 4 inches tall and repeat application 14 days later. If yellow nutsedge is greater than 6 inches tall at the first application, weed control effectiveness will be greatly reduced

Matrix is a group 2(B) ALS inhibitor; Sandea is the only other group 2 herbicide labeled and widely used in fruit crops. Matrix is a good tank-mix partner with the PS II inhibitors such as Karmex, Group 7(C2), or Princep, Group 5(C1), and the PPO inhibitors such as Chateau or Zeus, Group 14. However, growers should be reminded that population of common ragweed and marestail/horseweed in New Jersey have evolved resistance to ALS inhibiting herbicides. Therefore, we recommend that a foliar active herbicide with activity on common ragweed and marestail/horseweed  (such  as  paraquat or glufosinate)  must  be  tank  mixed  with  Matrix SG herbicide for  best  control  and  resistance  management when these weeds have already emerged.

Other commercial rimsulfuron herbicides may include these crops on the label. For instance, Solida from FMC includes blueberry and caneberry on the label

The new Supplemental Label is available from the internet at CDMS

Filed Under: Blueberry
April 18, 2018

Select Max Supplemental Label for Bearing Pome and Stone Fruits

The U.S. Environmental Protection Agency (EPA) has approved a new Supplemental Label for use of the graminicide Select Max 0.97 EC (clethodim) for bearing pome and stone fruits. This includes apples, pears and all other pome fruits, and apricots, cherries, nectarine, peaches, plums and related hybrids. The label also includes low-growing berry crops (except cranberry and strawberry), including low-bush blueberry. Previously it was only available for use on non-bearing fruits.

The label allows use of 12 to 16 fluid ounces (0.09-0.12 lbs active ingredient) per acre of Select Max in each application, with a maximum of 64 fluid ounces per acre per year. There is a 14-day pre-harvest interval (PHI) for all the tree fruit. The PHI for small fruit is 45 days. Always include 0.25% v/v non-ionic surfactant in the herbicide solution (1 quart in 100 gallons of spray solution).
Select Max is effective against all annual grasses, and is especially effective against annual bluegrass, which Poast (sethoxydim) tends to miss. Select Max at the highest labeled rate is moderately effective against quackgrass, orchardgrass and other perennial grasses.

Select Max is similar to the other graminicides, in that it kills grasses slowly. Visual symptoms (yellowing of the leaves) appear about one week after application. Normally, about four to five days after application, the tallest part of the grass plants can be pulled off and will have yellow discoloration at the node where it breaks off. Large, well-established grasses, especially perennials, may need a second application of Select Max or other grass herbicide three to four weeks after the first application to kill them completely.

The Select Max Supplemental Label is part of the Select Max Section 3 Federal label. The Supplemental Label expires in May 2019. By then these uses should be included on the Federal label attached to containers. The new Supplemental Label is available from the internet at CDMS

 

Filed Under: Tree Fruit
July 7, 2017

Getting the Upper Hand on Virginia creeper

Picture 1 – Virginia creeper vine

Virginia creeper (Parthenocissus quinquefolia) is a perennial woody vine that climbs on other objects or trails along the ground.  It is a common weed of orchards, vineyards and blueberry plantation. It is best identified by the typical palmate leaf with 5 leaflets that originate from the same point (picture 1).  Virginia creeper will produce many tendrils with adhesive disks at their tips that will allow the vine to climb upward and to attach to any support. It can grow under a wide range of conditions including dry sandy or moist organic soils, sunny or shady sites, and is tolerant to high salinity.  Plants will often establish through seeds dropped by birds who consumed the small blue berries in fall, but also by the spread of crawling stems that will produce new roots in contact with soil (picture 2). Virginia creeper is often confused with Poison-Ivy (Toxicodendron radicans). However, poison-ivy has 3 leaflets instead of 5 for Virginia creeper and lacks the tendrils and adhesive disks.

As a perennial weed, Virginia creeper will be tough to control as it can easily regrow after foliar injury from its extensive underground root system. When established, Virginia creeper will most often not be controlled with a single herbicide application, and multiple applications will be necessary to achieve acceptable control. Only nonselective postemergence herbicide (glyphosate) must be used to suppress or control this weed. In order to increase the efficiency of postemergence applications during the growing season, remove the vine from their support during winter pruning and lay it on the ground or plan a “cut stump” treatment during the growing season. Do NOT “prune out” the vine during the dormant season.

Picture 2 – Virginia creeper rooting stem

Spot treatment.  Glyphosate may be applied in mid- to late summer after vine flowers in early July until the first signs of fall color appear in the foliage. Good growth and maximum leaf area is needed at the time of herbicide application during the summer.  Wet a minimum of 50 percent of the weed foliage with a 1% glyphosate solution (1.25 oz of 4.5lb acid material per gallon of water) for effective control. For best control, don’t apply on stressed/wilted weeds.

Cut stump treatment. Best results are often obtained in late summer and early fall, but before fall color is observed in the foliage. Apply a 1% glyphosate solution to the cambial areas (inner bark area) of the stump of woody plants IMMEDIATELY after cutting. Cut and treat stumps only when the Virginia creeper is actively growing and not under stress.

WARNING. Injury due to root grafting may occur in adjacent plants. Do not treat cut stumps if there is a possibility of root grafting to desirable vegetation. Do NOT allow contact with green bark, trunk wounds, leaves, or root suckers of blueberry bushes.

The mention of trade names and rates is for educational purposes and does not imply endorsement by the author or the New Jersey Agricultural Experiment Station. Always defer to the product label for instructions on properly applying an herbicide.

Filed Under: Blueberry, Cranberry, Fruit, Strawberry, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: , , , ,
July 6, 2017

Liberty 280 SL label for LibertyLink sweet corn

 

EPA has recently approved a new version of Liberty 280 SL label (see picture).

This new label includes increased LibertyLink (LL) corn rates, increased yearly maximum rates, and a sweet corn section for LL varieties.

Liberty 280 SL is a non-selective herbicide that provides control of a broad spectrum of broadleaf and grassy weed species. Liberty can be used as a burndown treatment prior to planting or prior to emergence of corn, sweet corn, or soybean, as a post-emergence herbicide to control emerged weeds in LL varieties of corn, sweet corn and soybean.

Liberty is a group 10 herbicide (glutamine synthetase inhibitor) that has contact activity and control emerged weeds at the time of application. Liberty provides good to excellent control of various annual grass species, including barnyardgrass, crabgrass, foxtail spp., and fall panicum. Excellent control (> 85%) of tough to control broadleaf weeds has also been notes for pigweed, cocklebur, jimsonweed, lambsquarters, marestail, common ragweed, and smartweed.

Applications of Liberty should be made between dawn and 2 hours before sunset to avoid the possibility of reduced weed control. As with all contact herbicides, uniform spray coverage is necessary to achieve consistent weed control (use at least 15 gal/A in normal situations, 20 gal/A if dense vegetation is present). For best results, apply when weeds are 2-4 inches tall. Apply ONLY over the top of LibertyLink corn, sweet corn, and soybean varieties.

The mention of trade names and rates is for educational purposes and does not imply endorsement by the author or the New Jersey Agricultural Experiment Station. Always defer to the product label for instructions on properly applying an herbicide.

Filed Under: Field, Forage & Livestock, Vegetable Crops