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.

 

JUST RELEASED – INTERIM COVID-19 Guidance For Migrant & Seasonal Farmworkers, Their Employers, & Housing Providers

Cover 5-20-2020 NJ DOH Interim Guidance for Migrant-Seasonal Farmworkers

My apologies for not including our nursery growers that may also be impacted by this guidance when originally posted last week.

NJ Dept of Agriculture Secretary Douglas Fisher just announced, “At 3:30 today, we just received final approval to release the attached official guidance on migrant seasonal farmworker housing.”

The New Jersey Department of Health is partnering with its sister agencies New Jersey Department of Agriculture and New Jersey Department of Labor and Workforce Development to assist agricultural businesses and farm workers during the COVID-19 pandemic.

Please review the attached document carefully. This is titled INTERIM CORONAVIRUS DISEASE 2019 (COVID-19) GUIDANCE FOR MIGRANT AND SEASONAL FARMWORKERS, THEIR EMPLOYERS, AND HOUSING PROVIDERS.

Adopt these recommendations carefully for the protection of not only your workforce, but for you, your family and the entire ag community.

 

JUST RELEASED – INTERIM COVID-19 Guidance For Migrant & Seasonal Farmworkers, Their Employers, & Housing Providers

Cover 5-20-2020 NJ DOH Interim Guidance for Migrant-Seasonal FarmworkersNJ Dept of Agriculture Secretary Douglas Fisher just announced, “At 3:30 today, we just received final approval to release the attached official guidance on migrant seasonal farmworker housing.”

The New Jersey Department of Health is partnering with its sister agencies New Jersey Department of Agriculture and New Jersey Department of Labor and Workforce Development to assist agricultural businesses and farm workers during the COVID-19 pandemic.

Please review the attached document carefully. This is titled INTERIM CORONAVIRUS DISEASE 2019 (COVID-19) GUIDANCE FOR MIGRANT AND SEASONAL FARMWORKERS, THEIR EMPLOYERS, AND HOUSING PROVIDERS.

Adopt these recommendations carefully for the protection of not only your workforce, but for you, your family and the entire ag community.

 

NJ Dept of Agriculture Memo RE: Labor Housing Guidance Forthcoming

We’ve been asked to share the attached memo from NJDA Secretary Fisher regarding guidance on ag labor housing as it relates to COVID 19.

Root-feeding Pests of Cranberries

If your beds have damage caused by root-feeding insects, you should consider treatment with Imidacloprid (e.g. Admire Pro, Alias 4F, Alias 2F) immediately after bees are removed. Occurrence of root-feeding insects will manifest by the presence of dead patches (see picture). Pull dead vines and search through the root zone and soil for grubs and worms. Admire Pro (imidacloprid) is labeled for the control of cranberry rootworm, white grubs (Phyllophaga spp.), and other scarabs in cranberries.

White grubs, Phyllophaga spp. There are several species of white grubs that infest cranberries in New Jersey, the most abundant being P. georgiana. Grubs are C-shaped and often found near bog margins. Adults are reddish brown and nocturnal. Grubs attack the cranberry roots; adults have not been reported to feed on cranberries. See pictures of grubs and grub damage in cranberries. The life cycles and abundance of white grub species in New Jersey is not well known. Most likely, Phyllophaga grubs have a 3-year life cycle (based on previous reports and our own observations). Eggs are laid in late-June and July, and will hatch in July. First instars can be found in late-July and August and turn into second instars by the end of August-September. The second instar grubs will overwinter. These grubs will feed the following year until June and molt to third instars, which will overwinter. The following year, the third instars will feed for some time and then begin to pupate in June. Pupation will take place in July-August. Adults will appear in the soil in August-September. Adults will remain in the soil and overwinter. They will emerge in June, mate, and begin to lay eggs, completing the cycle.

Phyllophaga grub damage

Cranberry rootworm (Chrysomelidae). Pupation starts in late May and beetles emerge in early June. Adults are nocturnal and hide in leaf litter. Adults can be easily picked up in a sweep net. Females feed on foliage before laying eggs. Young larvae will feed on roots, feeding continues until October. The mature larvae move down the soil in the fall to overwinter. Holding of the water will delay onset of pupation. Rootworm has a 1-year life cycle. Entomopathogenic nematodes (Heterorhabditis bacteriophora) can be used to control cranberry rootworm.

Use of Imidacloprid. If treatment is needed, use imidacloprid (Admire Pro or other generic insecticides such as Alias 4F) to control white grubs and rootworms. Imidacloprid works best against early- (1st-2nd) instar grubs. Imidacloprid should be used soon after bees are taken out of beds. Because of the 3-year life cycle, treatment should be continued for 2-3 consecutive years to ensure control. Imidacloprid (active ingredient) is a neonicotinoid insecticide registered for use in cranberries against cranberry rootworm and scarab grubs. This insecticide is a contact and stomach poison that affects the insect

Phyllophaga grubs, pupa, and adults

nervous system. It is highly systemic and toxic to honey bees; therefore, can be used only as a post-pollination insecticide. Imidacloprid can be applied by ground or by chemigation. Aerial application of this product is prohibited. Imidacloprid has a long residual activity (> 100 days) as long as the insecticide is not directly exposed to the sun. Admire Pro can be used at 7-14 fl oz/acre. A maximum of 14 fl oz of Admire Pro can be used per acre per season. The PHI is 30 days.

Phyllophaga life cycle

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.