The Blueberry News Fall 2022

anticipate seeing not only a multitude of excited Jollibee patrons waiting to get their hands on their Jollibee favorites, but also first-timers waiting to have their own Jollibee experience," said Jose Miñana, Jollibee Foods Corporation's Group President for North America. "There's no greater joy for us than serving the needs and tastes of Jollibee fans in the community. At Jollibee, we aim to bring families together for happy moments over great tasting food with superior value, served with warm and friendly service –our own brand of joy." nostalgia and warm childhood memories for many overseas Filipinos in the U.S. To many, Jollibee is the go-to restaurant of Filipinos for both special

FALL & WINTER PREP

With the opening, Floridians will get to try Jollibee's signature menu items such as the world famous Chickenjoy. This dish is delicately breaded to be crispylicious on the outside and juicylicious inside. The well-loved Jolly Spaghetti is a favorite of both kids and kids-at-heart because of its signature sweetstyle sauce, loaded with chunky slices of savory ham, ground meat, and hotdog. Other classic menufavorites include the juicy and cheesy Jolly Hotdog, and the Peach Mango Pie, which is made with real Philippine sweet mangoes and a flaky golden brown crust.

ipation and excitement, Jollibee, the largest Asian restaurant company, is now open in Jacksonville. This is the 36th store in the US, as well as the first in the state and Southeast US. It opened to the public on March 18, 2017. Jacksonville is the most populous city in the Sunshine State, as well as home to the largest FilipinoAmerican community in Florida. The longawaited arrival of Jollibee in the city has

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“Nothing Runs Like a Deere” Test Drive One

8 A CRITICAL TIME FOR BLUEBERRIES

Fall may seem like a quiet time in blueberry fields, but important processes are silently occurring such as flower bud formation for next year’s crop and cold acclimation for the upcoming winter. When blueberry plants enter fall, they should have developed a canopy of moderately vigorous shoots with healthy leaves that developed following postharvest pruning during the summer. Here are some recommendations to consider for irrigation and fertilization.

17 EVERGREEN CHALLENGES

The evergreen production system for southern highbush blueberry (SHB) is used extensively in the south-central and central regions of Florida. Under this system, blueberry plants do not go dormant and are harvested early in the season. One of the primary management requirements in the evergreen system is to keep the foliage healthy and intact through the harvest season. A significant challenge to accomplishing this is fungal leaf disease, especially rust. This article will provide some background and information on this disease, as well as a suggested fungicide program to minimize the incidence and severity of rust.

28 UNFAIR IMPORTS

In early September, a bipartisan group of Florida’s congressional delegation, led by U.S. Sen. Marco Rubio and Rep. Al Lawson, filed a Section 301 petition on behalf of Florida’s fruit and vegetable producers. The Florida Blueberry Growers Association joined the Florida Farm Bureau, Florida Fruit & Vegetable Association, and Florida Strawberry Growers Association in support of the petition.

34

ALL

Chill hour accumulation is important for timely and vigorous spring growth in southern highbush blueberry (SHB). Some SHB cultivars exhibit slow or delayed leaf growth and canopy development during emergence from dormancy if grown in low-chill areas under the deciduous production system. Hydrogen cyanamide is a plant growth regulator often used, but there are cultivars that don’t respond well to HC Treatment.

Come, Meet, Learn, Apply

By now I hope you have scheduled a day to join your fellow Florida Blueberry Growers at our Fall Conference and Trade Show on October 20. If you come, you’ll get to meet with fellow growers with whom you have a great deal in common. They share many of the same challenges and rewards of growing blueberries in Florida that you do. You’ll learn about the latest research and advice from experts that are targeted specifically to growing blueberries successfully in our climatic conditions. I promise you’ll get more out of your participation at the conference than it costs you in the small amount of time and expense you invest.

Why not follow the business practice I was taught years ago when I justified attending much more expensive conferences: Always plan to find at least one good idea that more than pays for whatever the conference costs. It could be a better supplier, a better growing practice, a key industry contact, a better understanding of how the industry works. When you head back to the farm you’ll have some great ideas you can leverage for greater success. You’ll be better connected, more competitive, and more successful if you come to the Fall Conference.

It opens early at 8 a.m. and runs till 4 p.m. If you haven’t already registered, go to floridablueberrygrowers.org to register if you haven’t already. Reward some of your staff members with a day immersed in the industry. It’s held at Mission Inn in Howie-in-the Hills near Tavares. If you have to travel to get there, why not come Wednesday evening? We’ve reserved a block of convenient rooms to help out. Hope to see you there!

Thank You, Brittany Lee!

I also want to express some words of sincere appreciation for the hard work and dedication of Brittany Lee, our Past President and most recently the Executive Director of the FBGA. She has stepped down to focus her attention on her growing family and her Florida Blue Farms. We were fortunate to have her serve as Executive Director as she creatively sustained our association through the hard times of Covid. She also worked diligently behind the scenes to spearhead our fundraising and officially represent us in the fight for a favorable Section 201 ruling. Though the US International Trade Commission ruled against us, her hard work helped the powers that be understand the need to support American-grown blueberries. She continues to support our industry on a national platform through her work with USHBC, not to mention by growing great Florida Blueberries. Brittany, thanks for carrying our torch these past years!

PUBLISHER

Nelson Kirkland

MANAGING EDITOR

Jessica McDonald

ACCOUNT EXECUTIVE

Juanita Halter

LIAISON EDITORS

Doug Phillips, Jeff Williamson

CONTRIBUTING WRITERS

Doug Phillips, Jeff Williamson, Oscar Liburd, Phil Harmon

CONTRIBUTING PHOTOGRAPHERS

Doug Phillips, Jeff Williamson, Phil Harmon

CONTRIBUTING ARTISTS

Dawn Lewandowski

DELIVERY

DLS Distributors

Leonard Park President Florida Blueberry Growers Association

In the wake of Florida Blueberry Growers Association Executive Director Brittany Lee’s resignation, Beth Eng has agreed to serve the FBGA as an interim executive director.

Eng, who recently retired from WCJB TV20 after 25 years, and Lee collaborated on a project for the Alachua County Farm Bureau, creating the local Farm Fact on WCJB TV20 News in North Central Florida. Eng has been a volunteer with the FBGA since 2019.

If you need assistance, you can contact Eng at bethengemc@ gmail.com

P.O. BOX 358086

Gainesville, FL 32635

352-448-1418

OFFICERS

Beth Eng, Interim Executive Director bethengemc@gmail.com

Leonard Park, President president.fbga@gmail.com

Jerod Gross, Vice President fbga.vp@gmail.com

Michael Hill, Secretary michael@handafarms.com

Bobby Barben, Treasurer rhbjr@barbenfruit.com

BOARD OF DIRECTORS

Wayne Bass

Jerod Gross

Phil Harmon

Gary Smith

Kyle Straughn

Jeff Williamson

Doug Phillips

Travis Kuhn

2022 FBGA Fall Meeting and Short Course

Thursday, October 20, 2022

Mission Resort Inn and Club 10400 FL-48, Howey-In-The-Hills, FL 34737

• Chilli thrip management trial results –

Ms. Marice Lopez

• Blueberry disease update from the UF

IFAS Diagnostic Center –

Dr. Phil Harmon

• Blueberry breeding program research update and new cultivar release –

Dr. Patricio Munoz

• Irrigation study update and app development -

Dr. Michael Dukes

• Summary of the 2022 Florida blueberry season and new Growers Guide app moduleMr. Doug Phillips

• Blueberry research update -

Dr. Gerardo Nunez

• Blueberry pollination research update –

Dr. Rachel Mallinger

• Hydrogen Cyanamide trial results –

Dr. Jeff Williamson

RYAN ATWOOD Sales Representative P +1 352 267 3229 M atwoodag@gmail.com

Bigger, Better Blueberries Ready To Harvest With Fewer Passes

The benefits of Dormex make even more sense for today’s blueberry grower as labor gets harder to source and you make the move to mechanization.

Dormex helps manage the crop right from the start. You’ll see buds and blooms together, so the plants put more energy into the growing crop. The consistency of the berries makes all the difference when it’s time to harvest. With Dormex, you have more berries ready in a narrower window, so you can get more fruit with each pass. Fewer passes through the field means you have less impact on the plants and remaining berries.

For years, you’ve trusted your blueberries to Dormex to help you manage bud break, fruit size and uniformity. Now you can rely on Dormex to help with your harvest challenges as well.

JOHN STRICKLAND

Sales Representative

P +1 912 520 0220 M jwstrickland7@gmail.com

A Critical Time for Blueberries

Fall/Winter Irrigation and Fertilization Are Key to Bud Formation and Cold Acclimation

Fall may seem like a quiet time in blueberry fields, but important processes are silently occurring such as flower bud formation for next year’s crop and cold acclimation for the upcoming winter. When blueberry plants enter fall, they should have developed a canopy of moderately vigorous shoots with healthy leaves that developed following postharvest pruning during the summer.

Appropriate and well-executed irrigation, fertilization, and pest/ disease management programs are needed during the summer to produce and support this healthy summer growth flush. Research has demonstrated that healthy leaves are needed during the late summer and fall for flower bud initiation and de-

velopment which can begin as early as August in some cultivars, or as late as October in others, and continue throughout the fall. If significant defoliation occurs in early to mid-fall, flower bud initiation and development can be significantly reduced. Both the number of flower buds that develop and the number of berries produced by each individual flower bud can be negatively impacted by untimely fall defoliation. For deciduous production systems in north Florida, this usually means maintaining healthy leaves until late November/early December, or until hydrogen cyanamide (HC) is applied.

In Central and South-Central Florida, where winters are mild, plants may not enter true winter dor-

mancy, or if they do, the cool temperatures (accumulated chill units) needed for them to emerge normally from dormancy are often lacking. Under very low-chill winter conditions, HC applications have been unpredictable and largely ineffective. Therefore, many growers have adopted the evergreen production system, planting cultivars that were selected to perform well in that system. The goal of the evergreen production system is to avoid winter dormancy and the chilling requirement that goes along with it while maintaining a healthy leaf canopy through the winter into spring. This approach requires continued leaf disease management (rust is a particularly problematic pathogen during this time)

and some maintenance level of fertilization during fall and winter.

Currently, there is no published data for fertilization of southern highbush blueberries (SHB) using the evergreen production system. However, Dr. Gerado Nunez’s lab initiated a study this year with the goal of evaluating fertilizer practices using the evergreen production system (under tunnel) at the Plant Science Research and Education Unit in Citra, FL. Nunez will be presenting an overview of this project and other new research projects from his lab at the upcoming FBGA Fall Short Course.

Irrigation

Irrigation and fertilization are closely linked. The fertilizer elements must be in the soil solution to be absorbed by plants. Therefore, soil moisture is necessary, but overirrigation can leach fertilizer below blueberry roots where it is unavailable for plant uptake and may contaminate groundwater. Excessive irrigation can also promote certain soil-borne diseases such as . Water use of blueberry is high during the warm months of July, August, and September. However, during October, water use declines due to cooler temperatures and shorter days.

Research conducted over three growing seasons in North-Central Florida showed that the average amount of water used by mature “Emerald” plants declined by about 38% in October compared to September. Water use continued to decline progressively in November, December, and January as temperatures cooled, days shortened, and plants enter dormancy.

Irrigation programs should strive to keep the root zone moist, without applying water below the root zone. Knowledge of crop water demand, average rooting depth, the wetting pattern of the irrigation system, and the water holding characteristics of the soil will help achieve this goal.

Blueberry soils in Florida are somewhat unique in that they are often composed of sand with incorporated pine bark or solid pine bark beds. These types of beds have lower water-holding capacities than many agricultural soils that contain larger percentages of silt and clay. At field capacity, fine sand soil will hold only 0.04 to 0.09 inches of water per inch of soil compared to a loam or silt loam which holds 0.17 to 0.23 inches of water per inch of soil.

The water demand of a blueberry plant will depend on many factors such as weather conditions, plant size (canopy volume), canopy shape and structure, plant health, stage of growth, and other factors. But as stated earlier, plant water demand declines considerably during the fall and winter when compared to the summer growing season.

In a dormant production system in North-Central Florida, the average daily water use of large “Emerald” plants in October was about 1.3 gallons/plant /day and about 0.9 gallons/ plant/day in November compared to approximately 2 gallons/plant/day during the summer. However, these monthly averages vary widely depending on the environmental conditions on any given day.

Plant water use during the fall and winter will be influenced by the amount and condition of foliage present, and it will therefore generally be greater for evergreen production systems than for comparable dormant production systems. Various soil moisture monitoring devices are available to help track daily changes in soil moisture and assist with irrigation scheduling. With proper calibration and placement, moisture sensors can help growers determine when to irrigate and for how long.

For more information on soil moisture sensors see UF EDIS document

BUL 343, Field Devices for Monitoring

Soil Water Content (https://edis.ifas. ufl.edu/pdffiles/AE/AE26600.pdf).

Dr. Michael Dukes’ lab at UF has developed a phone application to assist blueberry growers with irrigation decisions. Dukes will present an overview of this research project at the upcoming Fall FBGA Short Course. The blueberry irrigation app can be downloaded here https://smartirrigationapps. org/blueberry-app/.

For additional information on irrigating and fertilizing Florida blueberries, please refer to UF EDIS documents Irrigating Southern Highbush Blueberry in Florida https://edis.ifas.ufl.edu/pdf/ HS/HS1432/HS1432-Dx4nsu6ek6.pdf and Nutrition and Fertilization Practices for Southern Highbush Blueberry in Florida https://edis.ifas.ufl.edu/pdf/ HS/HS135600.pdf.

JEFF WILLIAMSON, Horticultural Sciences Department, UF & DOUG PHILLIPS, Blueberry Extension Coordinator, UF/IFAS

USHBC Update

USHBC Developing Best-in-Class Data and Insights Program

With a goal of helping growers make data-informed business decisions, the U.S. Highbush Blueberry Council (USHBC) has launched an effort to develop a bestin-class data and insights program for the blueberry industry.

The first step toward making the project a reality was the hiring of Joe Vargas as the council’s director of business intelligence. In this role, Vargas is collecting, analyzing, and communicating data to growers and industry experts. He’s also building the Blueberry Industry Production and Pricing Data Collection Program, an industrywide analytics platform designed to educate growers and help expand blueberry demand globally.

USHBC recently selected Bytecode IO to assist with the creation of the production and pricing program.

“This program represents a pivotal moment for the blueberry industry –one that reflects our emphasis on the use of data to track the effectiveness of efforts to increase the production, sales and value of the blueberry crop produced domestically for U.S. consumption and export markets, and the sales and value of blueberries imported to the U.S.,” Vargas says.

“Participation from blueberry producers and marketers is crucial to the program’s success. USHBC is already working with a sample data set to start developing a model of the data capture and reporting. The second phase of work will expand on the initial sample set of data, ultimately reflecting a supermajority of blueberry volume, both imported and sold in the U.S.,” he added.

A deeper dive into the data and insights program, and the partner-

ship with Bytecode IO, is available on an episode of “The Business of Blueberries” podcast at bit.ly/3SgaURj.

“The USHBC is headed in a datadriven direction that will allow us to provide industry insights to help growers make decisions and help drive profitability. This is about more than inventories, what was sold yesterday and what we expect to sell tomorrow. This information will also highlight data like how blueberries are doing at retail and what consumers are looking for,” Vargas explains on the podcast.

Vargas will reveal the platform at The Blueberry Summit on October 5-7 in Nashville and explain how the industry can get involved.

There’s still time to register for the event at https://www.blueberryevents.org.

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Management Strategies For Fall

by DOUG PHILLIPS, UF/IFAS Blueberry Extension, JEFFREY G. WILLIAMSON, Horticultural Sciences Department, PHILIP F. HARMON, Department of Plant Pathology, OSCAR E. LIBURD, Entomology and Nematology Department, and PETER DITTMAR, Horticultural Sciences Department, all with the University of Florida/IFAS.

The following tables were updated from the 2022 UF/IFAS Florida Blueberry Integrated Pest Management Guide found at edis.ifas.ufl.edu/hs380. This publication is intended for use only as a guide. Specific rates and application methods are on the pesticide label, and these are subject to change at any time. Always refer to and read the pesticide label before making any application! The pesticide label supersedes any information contained in this guide, and it is the legal document referenced for application standards.

POLLINATOR PROTECTION

Before making insecticide applications, monitor insect populations to determine if treatment is needed. If insecticide application is necessary:

1. Use selective pesticides to reduce risk to pollinators and other non-target beneficial insects.

2. Read and follow all pesticide label directions and precautions. The label is the Law! EPA now requires the addition of a “Protection of Pollinators” advisory box on certain pesticide labels. Look for the bee hazard icon in the Directions for Use and within crop specific sections for instructions to protect bees and other insect pollinators.

3. Minimize infield exposure of bees to pesticides by avoiding applications when bees are actively foraging in the crops. Bee flower visitation rate is highest in early morning. Apply pesticides in the late afternoon or early evening to allow for maximum residue degradation before bees return the next morning. Bee foraging activity is also dependent upon time of year (temperature) and stage of crop growth. The greatest risk of bee exposure is during bloom.

4. Minimize off-target movement of pesticide applications by following label directions to minimize off-target movement of pesticides. Do not make pesticide applications when the wind is blowing towards bee hives or off-site pollinator habitats.

FALL AND EARLY WINTER DISEASES AND PESTS ALTERNARIA AND ANTHRACNOSE FRUIT ROTS

Alternaria fruit rot occurs most frequently when fruit is not timely harvested and remains on the bush for too long. Symptoms include darkgreen to black sporulation on ripe fruit and sunken areas near the calyx end of the berry. In postharvest storage, green to gray fuzzy growth may appear on infected fruit, especially if the berries have remained wet or were not properly cooled. Preventive fungicide applications can be made to help minimize disease development.

Anthracnose fruit rot is also referred to as "ripe rot." Infection may occur as early as bloom, with symptoms appearing as the fruit begins to ripen, including shriveling, development of sunken lesions, soft, rotted fruit, and eruption of orange- or salmon-colored spore masses on the blossom end of the fruit. In some cases, symptoms do not appear until after the fruit is harvested and stored. Fungicide applications from bloom through harvest prevent significant ripe rot losses most years when coupled with frequent hand-harvesting and rapid-cooling practices that are standard for southern highbush blueberry growers in Florida. Preharvest fungicides are especially important in years where there is a high incidence of disease in the field coupled with warm, wet weather, which can promote disease development. See Table 1 and EDIS publication PP337, “Anthracnose on Southern Highbush Blueberry” (https://edis.ifas.ufl.edu/publication/PP337).

BLUEBERRY GALL MIDGE

The blueberry gall midge (BGM) is a tiny fly whose larvae feed on vegetative and floral buds. Typically, gall midge will attack young developing floral and leaf buds, which will cause floral buds to abort or fall off the bush, resulting in poor flowering and “fruit set.” With heavy gall midge injury to floral buds, there would be a lighter bloom. Instead of the usual 5 to 6 buds producing several flowers, only 2 may reach maturity, resulting in poor fruit clusters. Blueberry gall midge will also feed on leaf or vegetative buds, leaving young leaves deformed and misshaped. Gall midges lay eggs on warm winter days and at any time during the growing season when the plants are making new flushes of growth. Delegate® (Spinetoram), Exirel® (Cyantraniliprole), diazinon (if labeled for use on your site), Apta® (Tolfenpyrad), and Movento® (Spirotetramat) can be applied for gall midge control between flower bud stages 2 and 3 (Figures 2 and 3). Application should take place when the most mature buds first show slight scale separation. Sprays may need to be repeated during warm spells. Bud scale separation may occur as early as December 15th in north Florida. Among rabbiteye cultivars, 'Premier' is often particularly attractive to the gall midge and is a good sentinel variety to monitor. Gall midge sprays can also suppress a prebloom thrips population. See Table 2 and EDIS publication ENY-997, “Blueberry Gall Midge on Southern Highbush Blueberry in Florida” (https://edis.ifas.ufl.edu/publication/IN1239).

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FALL AND EARLY WINTER DISEASES AND PESTS, CONT.

BOTRYTIS FLOWER BLIGHT

Botrytis blossom blight, caused by the fungus Botrytis cinerea, most commonly infects and blights wounded or senescent plant tissues. As a blueberry bush blooms, corollas (the fused petal of the flowers) senesce and become quite susceptible to infection. Ideally the corolla should drop from the flower after pollination but before senescence occurs. Frost damage on tender new growth may wound the plant, delay petal drop, and facilitate infection by the fungus. The development of Botrytis blight, like many other foliar fungal diseases, is highly dependent on environmental conditions. During bloom, periods of low temperatures combined with extended periods of high relative humidity result in more than 24 hours of leaf wetness and increase likelihood of significant disease development. If the blight continues, an entire cluster of berries can be aborted. When disease is severe, berry reduction can become economically important. Infected berries are sometimes deformed and may develop further rot if environmental conditions later become favorable for disease. After pollination of a flower and drop of the corolla, the risk of infection of the developing fruit is reduced. Economic loss due to Botrytis can be minimized by limited use of irrigation for freeze protection and judicious fungicide applications. See Table 1 and EDIS publication PP198, “Botrytis Blossom Blight on Southern Highbush Blueberry” (https://edis.ifas.ufl.edu/publication/PP119).

FLOWER THRIPS

These are small insects (i.e., 1/16 of an inch in length), yellowish to orange in color with fringed wings. Flower thrips damage blueberry flowers in two ways. Larvae and adults feed on all parts of the flowers, including ovaries, styles, petals, and developing fruit. This feeding damage can reduce the quality and quantity of the fruit produced. Females damage the fruit when they lay their eggs inside flower tissues. The newly hatched larvae bore holes in the flower tissues when they emerge. Flower thrips can be very damaging to flower buds and blooms. Thrips numbers typically increase dramatically as corollas open and bloom progresses. Determining when or if blueberries should be treated for thrips is difficult. Blueberries are a pollination-sensitive crop, and careless use of insecticides and subsequent bee kill can easily impair pollination and ruin fruit set. Only selected insecticides (Delegate®) should be used during bloom. If Delegate® is used, the insecticide should be applied in the early morning or late evening and be given 3 hours of drying time before bees are allowed to forage on the crop. To measure treatment thresholds for southern highbush and rabbiteye blueberries, begin sampling bloom clusters as soon as the flower begins to open. Sample four to five areas in a 1-acre block by placing a white sheet under a flower cluster and tapping lightly. Count the number of flowers and count the number of thrips dislodged from the flower cluster. If you average more than four thrips (southern highbush) or three thrips (rabbiteye) per flower, some type of management is recommended. Alternatively, two white sticky traps could be used to monitor a 5-acre block (one on the border and one in the center). If you have more than 80–100 thrips (southern highbush) or 60–70 thrips (rabbiteye), then some type of management tactic is needed. Assail® and Apta® are the material of choice until 5 days prebloom. See Table 2.

IMPORTED FIRE ANTS

Ant baits employed in early spring as a broadcast treatment usually eliminate most but not all fire ant mounds within treated areas. Under high ant pressure, treating a second time in the fall provides better fire ant control. Most ant baits are slow acting and require up to 8 weeks to control active mounds because they interfere with reproduction, causing a gradual colony die-off. Extinguish® Professional Fire Ant Bait (0.5% methoprene) is labeled for use on all crop land sites. It is effective but somewhat slower acting than Esteem® Ant Bait (0.5% pyriproxyfen). In order for the bait to be effective, active ant foraging is essential. Worker ants must be attracted to baits so that they will carry the baits back to their colonies. Ideally, temperatures should be warm and sunny. Ant baits work best when the soil is moist but not wet. Avoid applying ant baits when conditions are expected to be cold, overcast, rainy, or very hot. Individual mound treatments are most effective when used as needed for the occasional colony that survives broadcast treatments. Mound treatments using insecticide baits should be applied in a circle 3–4 feet from the mound. Baits should not be placed directly on top of mounds so that mounds remain undisturbed. The colony will move the queen to safety if mounds are disturbed. See Table 2.

PHOMOPSIS CANE AND TWIG BLIGHT

Phomopsis cane and twig blight is a fungal disease caused by Phomopsis vaccinii, which is spread to uninfected plants by wind and rain. Characteristic symptoms are dark-brown lesions on fruiting twigs (often surrounding floral buds), dieback of young twigs, and shriveling of flower and fruit clusters on diseased stems. Dying tissue may spread down the twig until most of the flower buds on an individual twig die. Shriveling of flowers and fruit clusters may appear similar to Botrytis damage. Control measures include fungicide applications and pruning out infected twigs.

PHYTOPHTHORA ROOT ROT

Phytophthora root rot (PRR) is considered the most serious soilborne disease that affects southern highbush blueberries (SHB). Some SHB cultivars are considered tolerant and others highly susceptible, while rabbiteye cultivars are less affected by the disease. PRR is caused by the oomycete pathogen Phytophthora cinnamomi. Common aboveground symptoms associated with Phytophthora infections are reductions in plant vigor and premature fall discoloration. Symptoms at ground level and belowground include crown and root rots. Disease on susceptible hosts occurs when certain environmental conditions (primarily a saturated root zone and root wounding) trigger Phytophthora reproduction, infection and symptom development. PRR is typically more severe in low and poorly drained areas of a farm. The pathogen causes root discoloration (dark brown to black, instead of the normal cinnamon brown) and decay. Advanced stages of infection cause plant stunting, wilting, an abnormal or reduced root system,

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FALL AND EARLY WINTER DISEASES AND PESTS, CONT.

PHYTOPHTHORA ROOT ROT, continued root rot, and plant dieback. Leaf discoloration also typically occurs, including yellowing, reddening with or without marginal burn, abnormal growth of new leaves, and defoliation. Plants affected by PRR may also be more susceptible to other dieback diseases including stem blight. Fungicides with the active ingredient mefenoxam, such as Ridomil Gold SL, are recommended where PRR occurs and are applied twice yearly (typically in January and June) through drip irrigation or as a band application directly to the bed. In addition to the phenylamide fungicide mefenoxam, which is applied to the soil, Aliette (Fosetyl-Al 80%) and numerous phosphorous acid products, referred to as “phites” or phosphonates, provide some control when applied as summer foliar sprays. See Table 1.

PREHARVEST FRUIT

SCALE

Scale insects injure blueberries by sucking plant sap, inserting their mouthparts into a plant and remaining immobile throughout their lives. Signs of infestation are leaf yellowing (chlorosis), defoliation, fruit drop, sooty mold, branch dieback, or plant death. Soft scales, Coccidae, secrete a waxy covering over the body. They also secrete a large amount of sugary waste (honeydew) resulting in sooty mold, which can interfere with photosynthesis and slow plant growth. Of the soft scales, Indian Wax scale, Ceroplastes ceriferus (Fabricius), is the most prolific on blueberries in Florida. See Table 2 and EDIS publication ENY-411, “Insect Management in Blueberries in the Eastern United States” (https://journals.flvc.org/edis/ article/view/116379).

SPIDER MITES

TABLE 1. DISEASE MANAGEMENT OPTIONS

The southern red mite is the key spider mite pest attacking blueberry plants in Florida. Southern red mites primarily infest the lower side of the leaf, giving the leaf a bronzing appearance when the population is high. Southern red mites also produce a protective web made of silk over the infested surface to protect them from predators. The underside of leaves should be closely examined with a 10x hand lens for adults, shed skins, and webbing. Tapping foliage onto a sheet of white paper can also be used to find adult mites. A few miticides, including fenazaquin (Magister®), fenpyroximate (Portal®) and acequinocyl (Kanemite®), have recently been labelled for spider mites. See Table 2 and EDIS publication ENY-1006, “Mite Pests of Southern Highbush Blueberry in Florida” (https://edis.ifas.ufl.edu/publication/IN1284). continued on page

Resistance to this fungicide in the ripe rot pathogen is common in central Florida. Use a Captan product in a tank mix where resistance is known. Subsequent applications can be made at 7-to-14-day intervals. Do not apply more than two sequential applications before switching to a fungicide with another mode of action (e.g., Switch®). Do not apply more than 1.44 qt per acre per season.

Applications can be made at 7-to-10-day intervals when conditions warrant. Do not apply more than 56 oz of product per acre per year. Make no more than two sequential applications before using another fungicide with a different mode of action.

Resistance to this fungicide in the ripe rot pathogen is common in central Florida. Use a Captan product in a tank mix where resistance is known. Do not mix Pristine® with anything other than Captan.

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TABLE 1. DISEASE MANAGEMENT OPTIONS, CONT.

Do not use more than 7.5 pt per acre per season. Do not tank mix with an adjuvant.

Do not make more than three applications per acre per crop year. Alternate with a fungicide with another mode of action.

Make up to 2 applications per year on a 7–10 day schedule. A tank mix with Captan is recommended for resistance management and to provide Botrytis suppression.

Do not apply more than 54.7 fl oz per acre per year. Rotate to a different fungicide group after no more than 2 applications. Reapplication interval is 7 to 14 days. Only Luna Tranquility is labeled by supplemental label for blueberry in Florida.

+++++ 12 h 0 days

Make the first application during early bloom. Subsequent applications should be made every 7–10 days during bloom. Do not apply more than 56 oz of product per acre per year. Make no more than two sequential applications before using another fungicide with a different mode of action.

Fluopyram + pyrimethanil (Luna Tranquility®)

+++++ 12 h 0 days

oz +++++ 12 h 0 days

Begin application at 10% bloom. Applications should be made every 7 days when conditions favor disease. Resistance is known to occur; do not make more than two consecutive applications without switching to a fungicide with a different mode of action. Do not apply more than 6.0 lb of product per acre per year. Pyraclostrobin +

Resistance is known to occur; no more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not apply more than four applications of Pristine® per acre per crop year. Do not mix Pristine® with anything other than Captan.

13.6–27 fl oz ? 12 h 0 days Do not apply more than 54.7 fl oz per acre per year. Rotate to a different fungicide group after no more than 2 applications. Reapplication interval is 7 to 14 days.

Ziram (Ziram 76DF) 3 lb ++ 48 h ~30 days Do not apply later than 3 weeks after full bloom.

Captan (Captan 50WP) 5 lb ++ 48 h 0 days Do not apply more than 70 lb per acre per crop year.

Captan (Captan 4L®) 2 qt ++ 48 h 0 days Do not apply more than 35 qt per acre per crop year. Phytophthora

(Aliette® WDG) 5 lb +++ 12 h 12 h Apply Aliette® as a foliar spray for Phytophthora and Pythium root rots and Septoria leaf spot. Subsequent applications can be made at 14-to-21-day intervals. Two or three fungicide applications following harvest are generally sufficient to prevent major outbreaks of Septoria leaf spot. Assuming that hedging is conducted immediately following harvest, this is a good time to consider an application. Do not exceed four applications per acre per year.

Do not tank mix with copper and foliar fertilizers and do not apply in acidic water or add acidifying agents, because these practices could damage fruit or foliage. When tankmixing this product with others, test the mix on a small area to make sure that phytotoxicity does not occur.

continued on page 18

Botrytis flower blight

Evergreen Challenges

Recommendations for Rust Management in the Evergreen System

The evergreen production system for southern highbush blueberry (SHB) is used extensively in the south-central and central regions of Florida. Under this system, blueberry plants do not go dormant and are harvested early in the season. One of the primary management requirements in the evergreen system is to keep the foliage healthy and intact through the harvest season. A significant challenge to accomplishing this is fungal leaf disease, especially rust. This article will provide some background and information on this disease, as well as a suggested fungicide program to minimize the incidence and severity of rust.

In Florida, rust on SHB is reported to be caused by the fungus Naohidemyces vaccinii. Plants with rust can show premature defoliation, decreased floral bud differentiation, and reduced yield. Different levels of susceptibility to this disease can be found in SHB; for example, certain

cultivars, such as “Jewel,” are known to be highly susceptible. A new collaborative project to characterize blueberry rust in Florida and sources of resistance within the UF Blueberry Breeding Program was started this fall and aims to improve understanding and growers’ options for resistant varieties.

Symptoms are initially observed as small, somewhat angular yellow spots, turning red to black, on the upper surfaces of leaves. This is usually limited by larger leaf veins, resulting in lesions with parallel straight or angular sides. Multiple lesions can occur on the same leaf, turning the leaves yellow and red over time (Figure 1) before causing defoliation. Yellow to orange rust colored spores appear on the underside of the leaf, opposite the lesions on the upper leaf surface, giving this disease its name. The presence of these spores is key to distinguishing this disease from other leaf spot diseases (Figure 2).

continued on page 36

Figure 1. Rust symptoms on upper side of leaf. Credits: P. Harmon, UF/IFAS

Figure 2. Rust symptoms on underside of leaf. Credits: P. Harmon, UF/IFAS

topic of the season

continued from page 16

TABLE 1. DISEASE MANAGEMENT OPTIONS, CONT.

days Established plantings: Apply 1/4 pt/1000 linear feet of row (3.6 pt per acre broadcast basis) in a 3-foot band over the row. One application prior to bloom and one additional application postharvest, approximately 6 months later. New plantings: Apply 3.6 pt per acre (broadcast rate) at or after planting. An 18-inch band over the row is recommended. Do not apply more than 0.9 gal per acre broadcast during the 12 months before plants bear harvestable fruit, or illegal residues may result. For both new and established plantings, one additional application may be made to coincide with periods most favorable for root rot development.

days Apply as a foliar spray for Phytophthora and Pythium. Also effective against Septoria and anthracnose leaf spots. Do not tank mix with copper and foliar fertilizers and do not apply in acidic water or add acidifying agents, because these practices could damage fruit or foliage. When tank-mixing this product with others, test the mix on a small area to make sure that phytotoxicity does not occur.

? 4 h 1 day Apply as a soil drench, as a soil-directed spray, or through irrigation system in spring before plants begin to grow, with a follow-up application postharvest prior to the rainy season.

to 55 fl oz ? 48 h 1 day Apply as a soil drench, as a soil-directed spray, or through irrigation system in spring before plants begin to grow, with a follow-up application postharvest prior to the rainy season.

TABLE 2. MITE MANAGEMENT OPTIONS

not apply more than 25 fl oz per acre per season.

Do not apply more than 19.5 oz of Delegate or 0.3 lb a.i. spinetoram per acre per season. Delegate® WG is toxic to bees until 3 h after application when it is thoroughly dry.

Do not apply within 4 days of bloom. Minimum application interval between treatments is 5 days.

days Entrust® is toxic to bees until it is thoroughly dry (3 hours), but thereafter it is relatively nontoxic to bees. Entrust® should be applied in early morning or late evening during bloom.

Malathion (Malathion 57 EC) 2 pt

Diazinon (Diazinon AG 500) 1 pt

Tolfenpyrad

5 days

Malathion has low toxicity to bees and beneficial insects.

days Do not apply within 4 days of bloom.

days Allow 14 days between applications.

Do not apply more than 19.5 oz of Delegate or 0.3 lb a.i. spinetoram per acre per season. Delegate® WG is toxic to bees until 3 h after application when it is thoroughly dry.

continued on page 22

Fall and Early Winter Suggested Blueberry Management Items

______ CREDIT

by DOUG PHILLIPS, UF/IFAS Blueberry Extension Coordinator

Remember to take a look at the UF/IFAS Blueberry Growers Guide phone app (now available in English and Spanish) for field scouting tools, as well as information on monthly management suggestions and all of the UF southern highbush blueberry cultivars.

iOS: https://apps.apple.com/ us/app/uf-blueberry-growersguide/id1535258711

Android: https://play.google.com/ store/apps/details?id=co.austn. ss.blueberry

The table below lists suggested blueberry management items for October through January. Suggested management items for the entire calendar year are available in an EDIS publication, Calendar for Southern Highbush Blueberry Management in Florida (https://edis.ifas.ufl.edu/publication/HS1363). Specific disease, insect, and weed controls are listed in the 2022 Florida Blueberry IPM Guide (https://edis.ifas.ufl.edu/publication/ HS380), as well as in subject-specific publications referenced below. Also, a list of all UF EDIS blueberry publications can be found at www.blueberrybreeding.com/blog, along with a summary description and link to each.

OCTOBER

Disease Monitor and manage leaf diseases, particularly in evergreen systems. See UF EDIS Publication PP348, Florida Blueberry Leaf Disease Guide (https://edis.ifas.ufl.edu/publication/PP348).

Insect Pests

Spray applicable insecticides or miticides to control blueberry bud mite if present or observed in prior season, southern red mites, and fall webworm. See UF EDIS Publication ENY-1006, Mite Pests of Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/publication/IN1284).

Weeds

Apply post-emergence herbicide if weeds are at densities that hinder bush growth. See UF EDIS Publication HS90, Weed Management in Blueberry (http://edis.ifas.ufl.edu/pdffiles/WG/ WG01600.pdf).

Disease Monitor and manage leaf diseases, particularly in evergreen systems. See UF EDIS Publication PP348, Florida Blueberry Leaf Disease Guide (https://edis.ifas.ufl.edu/publication/PP348).

Insect

Pests

Begin monitoring for blueberry gall midge using bucket traps (3-5 per acre) or sticky panel traps (1-3 per acre), and spray suggested insecticides when adults are observed. If traps are not used, spray suggested insecticides before floral bud break, with a second spray approximately ten days after the first application, following label directions. See UF EDIS Publication ENY-997 Blueberry Gall Midge on Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/ publication/IN1239). Continue monitoring for southern red mites and flat mites, and spray miticides and insecticides with efficacy on mites. See UF EDIS Publication ENY-1006, Mite Pests of Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/publication/IN1284).

Weeds

Apply post-emergence herbicide if weeds are at densities that hinder bush growth. See UF EDIS Publication HS90, Weed Management in Blueberry (http://edis.ifas.ufl.edu/pdffiles/WG/ WG01600.pdf).

DECEMBER – JANUARY

Disease

Once bloom occurs, monitor for Botrytis flower blight during cool wet periods. If present, spray suggested fungicides in rotation. Applications of fungicides prior to a forecasted need for overhead irrigation as freeze protection can help reduce Botrytis severity on plants damaged by low-temperature injury. See UF EDIS Publication PP198, Botrytis Blossom Blight of Southern Highbush Blueberry (https://edis.ifas.ufl.edu/publication/PP119). Anthracnose (ripe rot) infections can begin as early as bloom; consider preventative fungicide applications and use the Blueberry Advisory System for notifications of increased disease development risk (http:// cloud.agroclimate.org/tools/bas/dashboard/disease). January - Apply Ridomil to help prevent Phytophthora root rot. See HS1156, 2022 Florida Blueberry Integrated Pest Management Guide (https://edis.ifas.ufl.edu/publication/HS380).

Insect

Pests

Continue to monitor for blueberry gall midge and spray suggested insecticides when adults are observed. If traps are not used, spray before floral and vegetative bud break, with a second spray approximately 7-10 days after the first application, following label directions. See UF EDIS Publication ENY-997, Blueberry Gall Midge on Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/publication/IN1239). Also scout for scales, southern red mites and flat mites, flower thrips, and blueberry bud mites, and if observed use applicable control measures. See UF EDIS Publications ENY-1006, Mite Pests of Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/in1284) and HS1156, 2022 Florida Blueberry Integrated Pest Management Guide (https://edis.ifas.ufl.edu/publication/HS380) for detailed suggestions.

continued on page 24

topic of the season

continued from page 18

TABLE 2. MITE MANAGEMENT OPTIONS, CONT.

oz

Spider mites

Pyriproxyfen (Esteem® 0.86 EC Ant Bait)

Sivanto® You should allow a minimum of 7 days between applications.

4 h 3 days Entrust is toxic to bees until it is thoroughly dry (3 hours), but thereafter it is relatively nontoxic to bees. Entrust should be applied in early morning or late evening during bloom.

4.5–5.3 oz +++ 12 h 1 day Do not apply Assail® during bloom. It is an excellent prebloom spray. Application can be made 7 days prior to bloom. Assail® may negatively affect pollinating bees; therefore, application should be made in the late evening. Do not make more than four applications per season.

12 h 3 days Allow 14 days between applications.

1 pt/100 gal ++++ 24 h 7 days Mound drench. Slowly apply 1 gal of diluted mixture over and 6 inches around each mound. Apply gently to avoid disturbing ants.

1.5–2.0 lb (2–4 tbsp/ mound)

++++ 12 h 24 h Esteem® Ant Bait should be applied during the spring and, if needed, again in the fall. Apply on sunny days when the soil temperature is at least 60°F and the soil is moist. Baits are slow acting but effective. Allow 4 weeks to work. Do not make other imported fire ant treatments for 7–10 days. May need to reapply if heavy, flooding rains occur within 7 days.

1–1.5 lb (3–5 tbsp/ 1000 sq ft) (3–5 tbsp/ mound)

+++ 4 h 0 days

Extinguish® Professional Fire Ant Bait (0.5% methoprene) is legal for use on crop land. Caution: Extinguish baits with methoprene plus hydramethylnon are not labeled for use on crop land. Application during the heat of the day or when rain is expected within 6 hours of application will reduce the effectiveness of this product. In areas of heavy infestation, repeat applications may be necessary 10–12 weeks after the initial application.

Recommended 1–3 gallons per 100 gallons of water. Avoid using this product if the temperature is above 85°F.

days Apply in at least 50 gallons of water per acre. Use higher rates for heavier mite pressure. Do not make more than one application per year. Fenpyroximate (Portal®)

day Growers can make two applications per year.

continued on page 24

topic of the season

TABLE 2. MITE MANAGEMENT OPTIONS, CONT.

Hydrogen Cyanamide

continued from page 21

DECEMBER – JANUARY

Consider applying hydrogen cyanamide (marketed as Dormex, and BudPro) in deciduous production systems, in particular those with weak or delayed leaf canopy development and heavy fruit loads. However, at higher concentrations, it can cause floral bud injury and reductions in yield, especially in some cultivars that are more sensitive to hydrogen cyanamide, including ‘Jewel’, ‘Primadonna’, and ‘Colossus’. Growers should do test applications by cultivar on small sections to determine safe concentrations. In addition, application should be made before 20% of the floral buds are at or past stage 3 (separation of bud scales) and after sufficient chilling has occurred to minimize floral bud damage. See further discussion in UF EDIS publication HS976, Reproductive Growth and Development of Blueberry (https://edis.ifas.ufl.edu/publication/HS220).

Freeze Protection

Monitor forecasted and actual temperatures and utilize freeze protection strategies as needed. See UF EDIS publication HS968, Protecting Blueberries from Freezes in Florida (https://edis. ifas.ufl.edu/publication/HS216).

Pruning

Dormant pruning can be performed to maintain appropriate plant structure and size. Removal of approximately 25% of old canes should be done annually beginning when a plant is five to six years old, to promote the growth of new canes. Low branches, weak growth, and damaged wood can also be removed at this time. See UF EDIS publication HS1359, Pruning Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/publication/HS1359).

Managed

Bees

Have honey bees (and bumble bees if applicable) delivered; should ideally be placed in the field after 10% bloom but before 20% bloom. On large farms, hives should be distributed throughout the farm to the extent it still allows access to bee providers. Confirm the health of colonies upon delivery; at least 8 frames per hive should have adults, and at least 6 frames should have brood in the cells, with good activity into and out of the hives and on the bushes. Consider adding additional honey bee or bumble bee hives if there is a heavy, concentrated bloom across the farm, nearby competing crops or wild plants blooming at the same time, or ongoing poor weather conditions (cold, windy, or overcast). See additional details in EDIS Publication ENY-172, Pollination Best Practices in Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/publication/IN1237).

NELSON KIRKLAND, Publisher

Decisions, Decisions

IF ANYONE KNOWS the importance of planning, it’s Florida growers. Harvest time might steal the spotlight each year, but we know that every step we take and every decision we make during the other seasons can ultimately make or break the harvest. As we’re all so acutely aware, multiple factors to consider in your fall routines, including pests, irrigation, fertilization, and disease. This edition of The Blueberry News is full of best practices and recommendations from leaders in the field to help you set your crop up for success.

In our Field Management feature on page 8, we explain how fall/winter irrigation and fertilization play a crucial role in flower bud formation and cold acclimation. The article takes a closer look at the specific needs for evergreen production.

Inside, you also will find an update on hydrogen cyanamide and detailed information on how specific cultivars react to the pesticide.

On the topic of pests, be sure to check out the Bug of the Month feature, where the experts offer advice on protecting against southern red mite and blueberry gall midge. They also discuss the various pesticides approved for use.

As the industry as a whole continues to fight the flood of cheap Mexican crops coming across the border, the Florida Blueberry Growers Association is making its voice heard. The association recently joined the Florida Farm Bureau, Florida Fruit & Vegetable Association, and Florida Strawberry Growers Association in support of a Section 301 petition to protect Florida’s fresh fruit and vegetable farmers. The petition requests the U.S. Trade Representative to investigate the flood of crops from Mexico. Our peers are standing strong!

Last but certainly not least, don’t forget about the upcoming Fall Short Course, scheduled for Thursday, October 20. To register, go to https://www. floridablueberrygrowers.org.

grower 411

The Blueberry Advisory System, a Grower Tool For Timing Anthracnose Fruit Rot Controls

ANTHRACNOSE FRUIT ROT (AFR), also called ripe rot, is a fungal disease that can damage blueberry fruit, resulting in sunken lesions, softening, shriveling, and rotting of berries, along with eruptions of salmon-orange masses of spores. Symptoms typically start at the blossom end of the berry and cause the fruit to be unmarketable, affecting pack-out percentages and grower revenues. AFR infections can occur as early as bloom, with symptoms often not appearing until the fruit ripens or after it has been harvested and stored. Warm, wet weather is conducive to the development of AFR, with temperatures between 59-81°F (15-27°C) and leaf wetness duration of more than 12 hours the most favorable for infection. Rainfall or overhead irrigation disperses the pathogen to uninfected fruit and plants, creating additional opportunities for infection. The pathogen can also be spread by fruit-to-fruit contact, harvesting machinery, and sorting equipment.

Control of this disease depends primarily on protective fungicide applications, which many blueberry growers apply using a calendarbased method. Under this method, fungicide applications are made at regular intervals during fruit development, often every 14-21 days, which over the course of a season can be a significant cost. Fungicides suggested for use in a rotation to control AFR include Switch® (cyprodinil + fludioxonil), Captan, and Omega® (fluazinam). AFR in Florida has shown resistance to Abound® (azoxystrobin) and Pristine® (pyraclostrobin + boscalid).

The Blueberry Advisory System (BAS) is an alert system that signals Florida blueberry growers when environmental conditions are favorable for the development of AFR. The system is active from December through May. Data for AFR risk models is collected from the Florida Automated Weather Network (FAWN), which has weather stations throughout the state. Users select the FAWN site that is closest to their farm for alerts. The risk for AFR development is rated as low, moderate, or high (Figure 1), and growers who sign up for notifications

continued on page 35

Figure 1. Blueberry Advisory System disease risk rating. Credits: AgroClimate

For application rates and instructions, For application rates and instructions, please scan the QR Code. please scan the QR Code.

Unfair Imports

In early September, a bipartisan group of Florida’s congressional delegation, led by U.S. Sen. Marco Rubio and Rep. Al Lawson, filed a Section 301 petition on behalf of Florida’s fruit and vegetable producers.

“For too long, specialty crop growers across the U.S. have faced the devastating effects of unfair imports from Mexico,” said Mike Joyner, president of the Florida Fruit & Vegetable Association. “The urgency for immediate, effective, and enforceable relief cannot be overstated to support a U.S.-grown food supply and restore market fairness. The time to act is now.”

The Florida Blueberry Growers Association joined the Florida Farm Bureau, Florida Fruit & Vegetable Association, and Florida Strawberry Growers Association in support of the petition to protect Florida fresh fruit and vegetable farmers from the onslaught of heavily subsidized Mexican produce.

Under the Trade Act of 1974, the petition requests the U.S. Trade Representative to “conduct an investigation into the flood of imported seasonal and perishable agricultural products from Mexico.” It details the history of expansive government subsidies to Mexico’s fruit and vegetable sector, which are almost solely responsible for the corresponding decline in Florida production of fresh fruits and vegetables.

“Now is the time to deliver relief to domestic producers under assault from foreign imports, including blueberry growers,” stated FBGA President Leonard Park. “As a

nation, we must prioritize American food for our future generations.”

Over the last year, several reports have documented the economic impact of and the extraordinary challenges that domestic growers are experiencing amidst surging imports from Mexico. This includes reports from both the Florida Department of Agriculture and Consumer Services and the U.S. Department of Agriculture Economic Research Service.

This action follows fact-finding investigations by the U.S. International Trade Commission under Sections 201 and 332 of the Trade Act of 1974 for select commodities. These investigations were part of a larger suite of commitments jointly announced by the U.S. Trade Representative and the U.S. departments of Commerce and Agriculture in September 2020. The plan outlined specific actions each agency would take, and more than two years later, some of those commitments remain unfulfilled.

“The unfair trading practices have to be addressed with timely, effective, and durable measures in order to protect our nation’s food security,” said Kenneth Parker, Executive Director of the Florida Strawberry Growers Association. “Specialty crop farmers have done their best to hold onto the ground they have in the market, but now is the time for relief in order to ensure domestically grown produce stays on the grocery store shelves.”

FBGA Joins Agencies in Support of Trade Petition

Fall and Early Winter Bring Threat of Southern Red Mite and Blueberry Gall Midge

Two of the primary pests typically observed on southern highbush blueberries in Florida during the fall and early winter months are southern red mites and blueberry gall midge.

Southern Red Mite

The southern red mite is a type of spider mite that is usually found in higher numbers when conditions are warm and dry. Populations tend to peak during October through early November when rainfall has decreased but temperatures remain somewhat elevated (optimal temperatures are between 60 and 86°F). Their life cycle can be completed within two weeks under these conditions, and overlapping generations can occur under temperatures between 70 and 81°F, when populations can double within five days.

Southern red mite adults are

Figure 2. Bronzed leaf symptoms from mite feedings. Photo by D. Phillips, UF/IFAS

Figure 1. Adult southern red mites. Photo by O. Liburd, UF/IFAS

about 0.015 inches in length and are red or brown to deep purple in color, with lighter-colored legs (Figure 1). Females are slightly larger than males and have a more rounded body shape in the posterior, compared to the slender body of the males. Eggs are red to brown and spherical. Eggs hatch into pale, six-legged larvae, while the nymphal stages have eight legs and become progressively darker and larger.

The primary symptom associated with southern red mite injury is leaf bronzing (Figure 2), due to internal leaf damage from the mites inserting their mouthparts into the leaf and removing cell contents. This damage can result in a decrease in the rate of photosynthesis. The degree of bronzing is proportional to the amount of internal leaf damage from mite feeding. These mites primarily infest the lower side of the leaves, resulting in the accumulation of white shed skins when populations reach high numbers (Figure 3) and produce a protective web made of silk over the infested surface to protect them from predators.

Frequent scouting is recommended to identify early mite infestations during vegetative growth. Southern red mites can be seen with a 10X hand lens. While characteristic symptoms of mite feeding such as bronzed leaves are a good indication of mite infestations, these symptoms generally appear after moderate to severe infestation levels have already occurred and the risk of defoliation is high. Closely examine the underside of leaves to look for adults, shed skins, and webbing to detect the presence of the southern red mite. Growers can also sharply tap foliage onto a sheet of white paper to observe any adults.

Three miticides— Magister® with the active ingredient fenazaquin, Portal® with the active ingredient fenpyroximate, and Kanemite® with the active ingredient acequinocyl —have been registered for use in

highbush blueberries. The miticides control all developmental stages including larvae, nymphs, and adults of southern red mites. Growers can only make one application per year using Magister® and two applications each per year with Portal® and Kanemite®.

Blueberry Gall Midge

The blueberry gall midge (BGM) is a small fly native to North America that feeds on blueberries. In Florida, its larvae feed on floral and vegetative buds of southern highbush blueberry. Adult BGM are somewhat smaller than a mosquito, about 0.08 to 0.1 inches (females are larger than males) (Figure 1). The adult lives for only two to three days and becomes active when temperatures are warmer than 60°F. It is believed that mild winters characterized by cool and warm spells can result in higher midge activity. In Central Florida, adults typically become active in late fall (November to December), and peak activity appears to be in January and February. In

North Central Florida, adults are active in November; however, cool temperatures in December and early January can reduce midge populations. Peak activity in North Central Florida occurs from late February to March. A single female can lay as many as 15 eggs per bud, forcing its ovipositor between the folds of flower and leaf buds just after bud swell when scales begin to separate. Eggs hatch in two to three days into young larvae that are difficult to observe within the buds. The larvae are translucent to white for the first three to five days, eventually turning orange when they mature in about eight to 10 days (Figure 2). The larvae pass through three stages and during this time feed on the inside of floral and vegetative buds. The larvae then drop to the ground to pupate in the soil before emerging as adults. It is believed that adult males usually emerge about two weeks before adult females.

BGM larvae feed on the inside of floral bud tissues, resulting in necrosis, brown lesions, and bud abortion, with

continued on page 32

Figure 3. Shed mite skins on the underside of leaf. Photo by D. Phillips, UF/IFAS

bug of the month , continued from page 31

accompanying poor fruit set. With significant gall midge damage, there will typically be a lighter bloom since many of these buds will abort (e.g., only 1 or 2 florets may be seen instead of the usual 5 to 6, and therefore fruit clusters will produce only 1 or 2 berries per cluster). It should be noted that damage to flower buds (such as browning, shriveling, and disintegration) can also be caused by hydrogen cyanamide over-application or freeze damage. Poor fruit set and excessive dropping of undeveloped green fruit can also be caused by poor pollination.

BGM larvae are difficult to kill using contact insecticides because they are protected while inside the buds. Contact insecticide applications must be timed to kill adults before they lay eggs. Careful scouting and monitoring should be conducted to time insecticide sprays to kill adults early in the season. This can be done using clear sticky traps hung on the sides of blueberry bushes close to the ground, or by placing a white bucket trap with a sticky Plexiglas top under bushes in direct contact with soil or pine bark to detect new adults emerging from the ground (3–5 traps per acre). Recommended chemical controls should be used when two or more adults are present in the traps. At a minimum, monitoring for larvae should be done by placing young stems with buds into a Ziploc-type plastic bag at room temperature. If present, larvae will begin to emerge after three to four days. If traps are not used for monitoring, preventive spray applications can be made. The first application should be made right before floral bud break, with a second application 10 days later.

Two insecticides that have shown effectiveness against gall midge are Exirel® with the active ingredient Cyazypyr®, and Movento® with the active ingredient Spirotetramat.

These insecticides have systemic and translaminar activity that can target both larvae in floral and leaf buds and adults but cannot be used when pollinators are present. Neonicotinoids such as Assail® and Admire Pro® (imidacloprid) also have systemic activity and can kill larvae that are hidden between the bud scales but cannot be used when pollinators are present. The reducedrisk pesticide Delegate® (Spinetoram) is used for gall midge management when pollinators are present in the field. Once it has dried for 3 hours it has limited effects on bees. Delegate® will kill adult midges if it comes into contact with the adults; however, it

has relatively short residual activity and will need to be re-applied weekly. Because adults live for such a short time (two to three days) the chances of this pesticide being effective against midges are greatly reduced. Please read the label and follow all directions for rates, frequency of application, and restrictions for all pesticides.

Figure 1. Adult blueberry gall midge.

Photo by O. Liburd, UF/IFAS

Figure 2. Larval blueberry gall midge. Photo by O. Liburd, UF/IFAS

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One Solution Doesn’t Fit All Not All Cultivars Respond Well to Hydrogen Cyanamide

Chill hour accumulation is important for timely and vigorous spring growth in southern highbush blueberry (SHB). Some SHB cultivars exhibit slow or delayed leaf growth and canopy development during emergence from dormancy if grown in low-chill areas under the deciduous production system. Delayed leaf canopy development can result in slower fruit ripening, reduced fruit quality, and plant stress, especially for plants that set a moderate to heavy crop. Hydrogen cyanamide (HC), trade names Dormex™ and BudPro®, is a plant growth regulator that may be a useful tool for stimulating earlier and stronger spring leafing of certain SHB cultivars grown under the deciduous production system in Florida or in other low-chill areas. Where spring leafing is significantly advanced by

HC, the harvest season is often earlier and more concentrated than would otherwise occur. Increased berry weight (size) and a slight increase in total yield have also been noted in some cases, but the main advantages are earlier and more concentrated berry harvests.

Hydrogen cyanamide is classified as a restricted-use pesticide with specific requirements for its safe and legal application. These include specific requirements for protective gear, and specialized loading and spraying equipment (e.g., an enclosed tractor cab). Growers who are interested in using HC but lack specialized equipment, applicators license, or expertise for its effective, safe, and legal application, may want to consider custom application options. Hydrogen cyanamide should be kept under cool conditions, not to exceed

68°F and not stored in direct sunlight. New HC should be purchased each year rather than using leftover HC from the previous year. Orders are typically placed in the fall, allowing time for shipment to the southeastern United States. Considering the current supply chain issues, it is advisable to place orders as early as possible to ensure timely delivery.

Not all blueberry cultivars grown in Florida need or respond well to HC treatment and some cultivars are susceptible to injury (spray burn) from HC. SHB cultivars “Emerald,” “Farthing,” and “Patercia” have been grown successfully using HC in areas of north and North Central Florida where plants are exposed to enough cool weather to enter dormancy and receive some chilling. Recent research with “Optimus” suggests that its flower

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grower 411 , continued from page 26

will receive a text and/or email message when the risk is moderate or high. This allows growers to target their fungicide sprays to those periods when the development of infection is more likely, which may decrease overall applications for the season while achieving a comparable level of disease control.

Blueberry Extension Coordinator

MEMBERSHIP INFORMATION

To join or renew your membership in the Florida Blueberry Growers Association, mail a check payable to: FLORIDA BLUEBERRY GROWERS ASSOCIATION, INC. P.O. Box 358086 Gainesville, FL 32635

•Grower Member: $150 (Florida & out-of-state growers)

Additional Associate Member/Grower: $50 each

•Allied Member: $200 (equipment and chemical companies, etc.)

Additional Associate Member/Allied: $50 each

•Educational & Research Member: $10 (University and USDA members who do not grow blueberries commercially)

Figure 3. Table of AFR disease risk and conditions. Credits: AgroClimate

disease , continued from page 17

In evergreen production in central and south-central Florida, the rust pathogen can survive on infected leaves that remain on the plants throughout winter, and its spores are spread by wind. Spores can also survive over the winter on other evergreen plants of Vaccinium species in the areas surrounding production fields. New leaf infections can begin in spring during or just after harvest, and disease activity increases again in early fall.

The best method of control is the application of fungicides. Systemic fungicides move into infected leaves and potentially stop rust development. However, most products will only reduce or delay the amount of sporulation because fungicides do not effectively kill the fungus inside the leaf. Fungicides do a better job protecting against new infections, so making repeated applications to maintain a protective residue on the leaves is key to preventing the disease.

Although the same products are used, the timing and application strategy should differ between evergreen and deciduous production. Two reasons for this include the timing of disease occurrence and the differential importance of late-season foliage management between the two production systems. Rust, like all diseases, varies from year to year in the severity and exact timing of when outbreaks start and how bad they get. Typically, in deciduous production areas, rust comes in around or just after harvest, slows in the heat of summer, and picks back up during rainy periods of fall. Deciduous growers have been encouraged

to continue management inputs until late fall (about October) when the disease progress slows with drier weather. At that point, the disease contributes to defoliation without demonstrated yield impact the following year. The pathogen does not survive on dead leaves or stems like some other fungi can, so the amount of spores available when new leaves are pushed in spring has been drastically reduced.

In the southern evergreen-producing regions of the state, rust tends to be slow in summer, becoming problematic around the end of September or thereabouts. Disease pressure persists all the way through harvest and the summer hedge. There are other foliar disease concerns during summer that can require fungicide inputs like anthracnose and target spot, but in evergreen production, these applications don’t usually give the overlapping rust protection afforded to the deciduous system. That means a longer period of time when leaves need protecting, and often that translates to more fungicide inputs required. The same protection vs cure principle applies here in that once the disease becomes severe, options become fewer, less effective, and more costly. Severe rust in evergreen production can even infect and blemish fruit if left unchecked.

Options to consider: Chlorothalonil (sold as Bravo and others) applications starting late fall, before bloom. Chlorothalonil is a contact fungicide that we cannot use after bloom and that some growers have concerns about causing leaf burn in the heat of summer. When not used during summer, these apps made when disease pres-

sure is generally low and starting to increase make good sense. As the season progresses, scout for rust disease. Scouting means walking rows, turning over leaves with spots and looking for the orange spore masses. As rust starts to pick up on the interior lower canopy leaves, consider using Proline (prothioconazole). It has stood out in some published research as an excellent choice among DMI products for rust. Other DMI’s with longer PHI’s can also be considered if rust picks up much before bloom (examples: Indar, Tilt). They will have some efficacy, and this will leave the Proline option (7-day PHI) for flare-ups closer to harvest. Abound and Pristine both also have rust efficacy and make for good rotations with one of the DMI’s. If applied at or after bloom, consider tank mixing a captan product with Abound or Pristine, because of the widespread anthracnose ripe rot resistance to these products. One or more of these options employed in the late fall to pre bloom period should do a good job of keeping rust severity low through harvest. These preventive measures will yield better results than those employed once defoliation and fruit infections are common in the field.

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SHB cultivars “Emerald,” “Farthing,” and “Patercia” have been grown successfully using HC in areas of North and North Central Florida where plants are exposed to enough cool weather to enter dormancy and receive some chilling. Recent research with “Optimus” suggests that its flower buds are sensitive to HC and significant flower bud thinning may occur. In “Optimus,” some advancement in fruit harvest was observed, likely due to flower bud thinning with what appeared to be a reduction in total yield. No or very low doses of HC are suggested for “Optimus” with the understanding that significant flower bud thinning and associated yield reduction are likely to accompany any advancement in harvest date. “Colossus” does not currently appear to be a strong candidate for HC.

buds are sensitive to HC and significant flower bud thinning may occur. In “Optimus,” some advancement in fruit harvest was observed, likely due to flower bud thinning with what appeared to be a reduction in total yield. No or very low doses of HC are suggested for “Optimus” with the understanding that significant flower bud thinning and associated yield reduction are likely to accompany any advancement in harvest date. “Colossus,” which typically sets fewer flower buds than other cultivars and ripens early in the season, does not currently appear to be a strong candidate for HC. Preliminary tests suggest that “Sentinel” does not benefit from HC sprays in North Central Florida. Suggested use of HC on newer cultivars may change with

with unknown response to hydrogen cyanamide.

Many variables come into play for a successful HC response. In addition to cultivar specificity, plant condition, and environmental conditions prior to, during, and immediately after treatment are believed to affect the response to HC. Plants should be completely dormant prior to treatment and have received some natural chilling. HC application is not advisable for evergreen blueberry production. For deciduous blueberry production, the exact threshold of pre-chilling needed is not known and likely varies among cultivars. Generally, under Florida conditions, the more chilling that occurs prior to HC application, the better the response on cultivars that

before a significant percentage of the flower buds have passed developmental stage 2 (flower buds swelling but bud scales still closed. For illustrations of flower bud development stages, see EDIS pub. 2022 Florida Blueberry Integrated Pest Management Guide HS1156 https:// edis.ifas.ufl.edu/pdf/ HS/HS380/HS380Dnt92580jc.pdf.

Since application is based on anticipated bud break and flower bud development, the timing may vary with location and year, but HC is typically applied in north-central Florida between mid-December and early January. Hydrogen cyanamide may interact with oil sprays and sprays containing copper or oil and copper. Refer to product labels for information on timing sprays to avoid negative interactions. Additional information on the use of HC in southern highbush blueberries can be found in the Florida Blueberry Integrated Pest Management Guide HS1156 https:// edis.ifas.ufl.edu/pdf/ HS/HS380/HS380Dnt92580jc.pdf.

Remember to always refer to and read the pesticide label before making any application. The pesticide label supersedes any information contained in this article, and it is the legal document referenced for application

Are You Licensed?

Blueberry varieties developed by the University of Florida are patent protected under U.S. Code Title 35. Anyone propagating plants for their own use or for sale is required to be licensed by Florida Foundation Seed Producers, Inc. (FFSP). Additionally, packers, marketers, and sellers of fruit from the above varieties can be liable for selling fruit from illegally propagated plants. As of Sept 30, 2022, the above entities are the only entities licensed for legal propagation and sale of plants of the respective varieties. Protect yourself from unknowingly purchasing illegal plants or fruit by asking entities if they are licensed to propagate and if fruit has come from legal plants. Illegal propagation is a direct threat to the blueberry industry and the patent rights held by FFSP. Royalties generated are critical to the support of the Florida blueberry breeding program. If you are interested in obtaining a license or would like to anonymously report illegal propagation, please contact: FFSP, 3760 NW 83rd St, Suite 2, Gainesville FL 32606, Phone: (850)-594-4721 ext. 108. You can also visit http://ffsp.net to learn more about licensing oppportunities.

x = Licensed for USA

x¹ = Licensed for USA (excluding AZ, CA, OR, and WA)

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