UF Evaluates Cold Hardy Citrus

The relatively mild winter temperatures during the last two decades has led to a resurgence of interest in cold hardy citrus in North Florida. Satsumas account for almost all of the new commercial citrus acreage in the Florida Panhandle.

If the next two decades have mild winter temperatures like the last two decades, Florida growers can successfully grow other cold-hardy citrus for the fresh market.

The citrus varieties that ripen before Christmas probably have the best chance for success in North Florida. At the Research Center in Quincy, many citrus species/varieties and numbered selections are under evaluation. The following is a list of the named varieties being evaluated.

Although we have had good crops the last two years, I cannot recommend it for north Florida because of a late (late Jan. thru March) ripening date. In addition, other fresh market citrus offer more potential. There is also a new early ripening Valencia that we have not yet tested. The data in Table 1 reflect fruit that were not quite ripe.

Navel and Red Navel
Navels have performed very well. I would estimate that our 12 year old trees have produced 400+ lbs per tree this winter. Little or no problem with Alternaria or citrus scab diseases. Our young trees also seem to be moderately cold hardy as well. Navel should be under consideration for north Florida. Harvest time can be just before Christmas.

Tango is a seedless Murcott, although many fruit have a few (< 5 seeds per fruit when grown in a mixed block. Tango produces a small but sweet fruit. It is easy to peel. Cold tolerance is moderate. The two disadvantages are a late ripening period (Jan.) and extreme susceptibility to citrus scab.

Nova mandarin was derived from a Clementine x Orlando Tangelo cross. It produces a small-medium sized fruit. Maturation is late January. It appears to be moderately cold hardy. More information is needed.

Early Pride
Early Pride is low seeded Fallglo. It is an early maturing Mandarin hybrid. It produces a high quality, small-to medium-sized fruit with good flavor. It is easy to peel. Unfortunately, it is the least cold hardy (severe damage below 25 to 26 °F) of all the citrus that we have in our collection, and it cannot be recommended for north Florida.

Sugar Belle
Sugar Belle was derived from a Clementine x Minneola Honey Belle cross. This mandarin hybrid is perhaps the most cold hardy of all non-satsumas in our trial. It produces a very attractive, bell-shaped fruit that is very high in sugar. It also is slightly higher in acid than is optimal. Fruit can have quite a few seeds when grown in a mixed block with citrus that can serve as pollinizers. Ripening date is November thru December. Sugar Belle could be considered for north Florida.

Minneola Honey Belle
Minneola is an older cultivar that produces an attractive, medium-large, bell shaped fruit. It is less cold hardy than Sugar Belle and has a later ripening time period (late December). Minneola is very susceptible to Alternaria fungus, and a spray program is required for commercial production.

Xie Shan
Xie Shan is an early ripening satsuma variety that ripens during October. In previous years Xie Shan has produced large, bumpy fruit that were not suitable for marketing. This year they produced a heavy crop (300 pounds/tree) of sweet, moderate-sized fruit. More observations are needed before I can recommend this variety.

Owari is the most popular satsuma variety. It produces a consistent crop of small to medium-sized fruit. Owari and all satsumas are cold hardy down to about 12 to 14°F if the trees are cold acclimated. Ripening date is mid-November. It has performed well on Swingle and trifoliate orange rootstocks.

Brown Select
Brown Select is the satsuma variety that produces the largest tree and fruit size.  It ripens between between Xie Shan and Owari (early November). It has performed well on Swingle and trifoliate orange rootstocks.

source: nwdistrict.ifas.ufl.edu


H-2 A Legislation

House bill aims to move H-2A program to USDA
U.S. House Republicans Elise Stefanik and Chris Collins of New York have introduced the Family Farm Relief Act of 2017, which would seek to move the H-2A program from the Department of Labor to the U.S. Department of Agriculture.

Its purpose is “to amend the Immigration and Nationality Act to simplify the petitioning procedure for H–2A workers, to expand the scope of the H-2A program, and for other purposes.”

The bill calls for USDA to establish electronic filing of petitions for nonimmigrant visas, with the option of submitting a paper petition.

It also seeks to repeal the 50 percent domestic workforce requirement, allow farm cooperatives and other agricultural associations to apply for workers for their members, make the program more workable for dairy and other livestock operations, and require reporting to Congress if delays occur in the H-2A visa application process.

Use of Mycoshield on Citrus

New Product Called on to Defend Citrus From Scourge

Dr. Bob Bruss is Director of Technical Services for Nufarm, the manufacturer of a bactericide that has been approved for use on citrus to improve tree health of HLB-infected trees. Here, he gives insight on how the product works and ways to use it effectively and efficiently.

How should Mycoshield be applied when treating Florida citrus trees for HLB?

Bruss: At present, Florida growers are operating under a Section 18 (specific exemptions), which spells out use instructions and restrictions. FFVA is now working with FDACS seeking a renewal from EPA of the Section 18. Nufarm recommends applying 1½ pounds of Mycoshield per acre along with a high-quality penetrating surfactant. Growers have the flexibility to apply up to eight times per season with a 21-day preharvest interval.

When are applications of Mycoshield most effective?

Bruss: The last two years of research demonstrate Mycoshield is taken into citrus trees most effectively during periods of active leaf flushing. Generally, the greatest flushing occurs in spring and fall. This timing also corresponds to greater activity of HLB in plant tissues vs. summer when bacteria may drop naturally.

Can Mycoshield be tank-mixed with other standard products without impacting performance?

Bruss: It appears many growers are tank-mixing Mycoshield with a wide variety of other products normally used in a spray program. We have not received reports of either compatibility or phytotoxicity issues. Foliar applications of Mycoshield alone are not phytotoxic. However, some combinations of Mycoshield — plus other pesticides, surfactants and/or fertilizers — may cause crop injury. The crop safety of any Mycoshield mixture must be verified on a few trees before making a commercial application.

What are the recommendations for rotation of Mycoshield when applying to citrus?

Bruss: Oxytetracycline is the ultimate active ingredient resulting from an application of Mycoshield. This is a reversible bacteriostat that suppresses protein production in target bacteria. Multiple applications of oxytetracycline at frequent intervals are needed to starve the bacteria of essential proteins until they perish. Nufarm does not consider streptomycin to be an effective comparable bactericide on HLB. This is largely based on an independent published study conducted by M Zhang et al. (2014) at the UF/IFAS Indian River Research and Education Center. Lemon budsticks severely infected with HLB were soaked overnight in a solution with a high concentration of streptomycin sulfate and subsequently grafted onto disease-free grapefruit rootstocks. The young trees were evaluated after six months. The lemon scions had an 80% incidence of infection and 65% of the grapefruit rootstocks were infected despite the exposure to a high concentration of streptomycin sulfate. However, streptomycin may have some value in summer sprays for control of citrus canker. Streptomycin is an irreversible bactericide that has beenfrequently selected for commercial-level resistance in fire blight and other plant diseases. In more than 25 years of Mycoshield commercial use, Nufarm is aware of only a single orchard with documented fire blight resistance in California, and no confirmed commercial-level resistance to bacterial spot in peaches.

What are you hearing from growers regarding the trees’ response to applications?

Bruss: Generally, growers are reporting visual improvement in tree health and research consultants working with Nufarm on Florida trials are observing similar patterns. Since Mycoshield is a suppressive tool, we expect some larger, older trees may not respond as rapidly as younger plantings. Additionally, we expect tree health to show continued improvement the second year of treatment due to cumulative bactericide HLB-suppressive effects.

When would you expect to see more visual and/or yield impacts from the applications?

Bruss: Our research trial fruit drop/yield data will be evaluated in the near future. As stated, we also expect there to be a cumulative improvement next season into the summer. Hopefully, many of the trees that were treated in 2016 will have an improved leaf flush this spring. This in turn will provide more young foliage to absorb the 2017 applications leading to additional improvement in tree health.

USDA Invests $13.6 Million in Citrus Greening Research

WASHINGTON, Jan. 19, 2017 – The U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA) today announced four grants totaling more than $13.6 million to combat a scourge on the nation’s citrus industry, citrus greening disease, aka Huanglongbing. The funding is made possible through NIFA’s Specialty Crop Research Initiative (SCRI) Citrus Disease Research and Extension Program, authorized by the 2014 Farm Bill.

“The economic impact of citrus greening disease is measured in the billions,” said NIFA Director Sonny Ramaswamy. “NIFA investments in research are critical measures to help the citrus industry survive and thrive, and to encourage growers to replant with confidence.”

Huanglongbing (HLB) is currently the most devastating citrus disease worldwide. HLB was first detected in Florida in 2005 and has since affected all of Florida’s citrus-producing areas leading to a 75 percent decline in Florida’s $9 billion citrus industry. Fifteen U.S. States or territories are under full or partial quarantine due to the presence of the Asian citrus psyllid (ACP), a vector for HLB.

Since 2009, USDA has invested more than $400 million to address citrus greening, including more than $57 million through the Citrus Disease Research and Extension Program since 2014. Awards for grant applications submitted in FY 2016 include:

  • Clemson University, Clemson, South Carolina, $4,274,523
  • Regents of the University of California, Riverside, California, $5,112,000
  • Iowa State University, Ames, Iowa, $2,476,099
  • USDA Agricultural Research Service (ARS), Athens, Georgia, $1,821,197

Funded projects include Clemson University researchers using naturally HLB-resistant citrus trees to develop new resistant varieties using the CRISPR-Cas9 genome editing tool. The Regents of the University of California project will design and identify HLB bactericides based on both natural and nanotechnology approaches. Researchers at Iowa State University will investigate the use of sustainable, naturally occurring soil bacteria to control ACP. The ARS project will identify and assess the effectiveness and economic viability of chemotherapy treatment options.

More information on these projects is available on the NIFA website.

Among past projects, the University of Florida developed bactericides to help recover fruit production in HLB-affected orchards. Research at the University of California used virulence proteins to develop strategies for creating citrus rootstocks that are immune to HLB.

NIFA is a member of the federal Multi-Agency Coordination (MAC) group to help deliver near-term tools to citrus growers to combat HLB. In addition, NIFA support to the National Plant Diagnostic NetworkThis is an external link or third-party site outside of the United States Department of Agriculture (USDA) website. helps plant diagnostic laboratories share best practices and expedite diagnoses and screening for ACP and HLB. The network coordinates diagnostician training in HLB with USDA’s Animal and Plant Health Inspection Service’s Plant Protection and Quarantine. These services enable rapid and accurate diagnoses and support U.S. food security.

Since 2009, NIFA has invested in and advanced innovative and transformative initiatives to solve societal challenges and ensure the long-term viability of agriculture. NIFA’s integrated research, education and extension programs support the best and brightest scientists and extension personnel whose work results in user-inspired, groundbreaking discoveries that combat childhood obesity, improve and sustain rural economic growth, address water availability issues, increase food production, find new sources of energy, mitigate climate variability and ensure food safety.

To learn more about NIFA’s impact on agricultural science, visit www.nifa.usda.gov/impacts, sign up for email updatesThis is an external link or third-party site outside of the United States Department of Agriculture (USDA) website. or follow us on Twitter @usda_NIFAThis is an external link or third-party site outside of the United States Department of Agriculture (USDA) website., #NIFAimpactsThis is an external link or third-party site outside of the United States Department of Agriculture (USDA) website..

Best Practices For Bactericides

December 5, 2016

sprayer applying bactericides to citrus trees
Bactericide applications during cooler times of the year, when HLB bacteria is more active, will be most effective.
Photo by Frank Giles

Without a doubt, the biggest news in Florida citrus during 2016 was the clearance for applications of three bactericide products aimed at improving the health of HLB-infected trees.

The products, FireWall 50 (streptomycin, AgroSource), FireLine 17 (oxytetracycline, AgroSource), and Mycoshield (oxytetracycline, NuFarm) were first approved by a crisis declaration from Florida Commissioner of Agriculture Adam Putnam, which cleared the way for spring flush applications of the products. Subsequently, a Section 18 was granted by EPA for continued applications for the remainder of the year.

The Section 18 was more difficult than most because applications were intended to improve tree health. According to the Florida Fruit & Vegetable Association (FFVA), who is the official petitioner on behalf of the registrants, the documentation sent to FDACS supporting the exemption was four times larger than usual petitions.

“We were very fortunate to have gotten there so quickly,” says Taw Richardson, President and CEO of AgroSource. “We also were fortunate to have Commissioner Putnam who was willing to jump in and push the envelope and his FDACS team for the crisis exemption in March and then the Section 18 that came in August. Without them and FFVA, none of this happens.”

How Do The Trees Look?

Now, with most growers having applied several applications of the bactericides, all eyes are on the trees looking for clues if the materials are having the intended effect of improving tree health, reducing fruit drop, and improving yields.

Most growers are in agreement that trees do look better than last season. How much of that can be attributed to the bactericides or to a season of good growing weather is still open to question.

“I think a high percentage of the growers are seeing tree health improvement, but it is too early to tell to what extent the yields have or will increase,” says Steve Futch, a Regional Citrus Extension Agent based in Southwest Florida.

While it is still early, Richardson says there are some good signs that trees are responding the way research plots indicated they would.

“Our trials do tell us what we see behind both canker and HLB treatments of these products. We have been sticking fruit on trees,” he says. “We would anticipate that to be happening, but there is still some question of how much is based on their [spray] program or how much of it is other factors. Or, how well will the trees continue to hold the fruit later in the season?”

The USDA’s November 2016-2017 Florida citrus production estimate rose by 2 million boxes based on a lowering of the percentage of anticipated fruit drop. Regardless of the cause, it’s a welcome sign for growers.

“As long as growers are staying on the recommended programs, we feel like after two years, we should be able to nail down what is happening and allow growers to feel more confident they are seeing positive results with the bactericides on tree health,” Richardson says.

Best Practices

Richardson says he is very pleased that growers seem to be following technical recommendations on applying the bactericides.

“When we saw results of the Citrus Research and Development Foundation survey on bactericide usage for the early season and growers’ plans for balance of the season, it appears they have really followed the program we have recommended,” he says.

Growers appear to be rotating the active ingredients to avoid potential resistance and making a sufficient enough number of applications to take full advantage of the materials.

“We are recommending growers rotate active ingredients depending on the citrus type and the time of the season,” he says.

“We want growers to cluster applications during the cooler times of year when the HLB bacteria is most active. So, we are looking at late summer to early fall applications followed by late winter to spring applications. Right now (at presstime), we think growers on a full program have made about four applications.”

Richardson stresses that applying the bactericides with the recommended adjuvants is critical to performance.

“The recommendations on adjuvants are based on significant research on their ability to move the active ingredients of FireWall and FireLine into the tree systemically,” he says. “That was the biggest part of our early research and the real breakthrough proving we can get these products in the tree where they can kill the HLB bacteria.”

Most growers are applying bactericides in the tank with other materials that are part of their regular production programs. There have been no significant reports of problems associated with tank-mixing the bactericides.

Labels and technical bulletins on pro-per application methods can be found on the company websites at (AgroSource.net) and (NuFarm.com).

How Is The Citrus FAST TRACK Program Faring?

In 2002, former U.S. Secretary of Defense Donald Rumsfeld famously said, “As we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns — the ones we don’t know we don’t know.”If we didn’t know better, we would think that Mr. Rumsfeld was a citrus grower planting experimental FAST TRACK selections.

In case you need a refresher: FAST TRACK is a system co-developed by UF/IFAS, Florida Foundation Seed Producers Inc. (FFSP), and New Varieties Development and Management Corp. (NVDMC) designed to enable growers and nurseries to engage with promising experimental UF/IFAS fresh citrus selections much earlier in the process.

Now that the oldest FAST TRACK trees are two years old, growers are looking for a barometer check on their performance. There is some fruit on some trees, but not all of the selections are fruiting. When the program was first launched, collaborative efforts were made to develop survey forms for gathering information about the selections. However, early interest was entirely focused on the fruit. We have yet to develop a means of gathering information about tree health and tree performance.

NVDMC reached out to many of the FAST TRACK growers and nurseries for a candid evaluation of the program. Growers have been responding and the results are interesting, though somewhat predictable. Nursery surveys were sent a few days later and results were not available by the deadline for this article. Nursery input will be revisited with FNGLA’s Citrus Nursery Division.

Here is a compilation of the most common answers to the grower survey questions:

What do you like most about the FAST TRACK Program?

• The opportunity to get experience with these selections soon after they are identified. I need answers and this trial helps keep me on the cutting edge.
• The option to roll the dice on commercial plantings — if I wish to do so.
• Being rewarded for my efforts with lower royalty and a production head-start, should any of my selections move to the commercial level.

What do you like least about the FAST TRACK program?

Inconsistencies. I often do not get the rootstocks that I ordered or the quantity of trees that I ordered. Though I understand that things can happen at the budwood or nursery stage, this makes it difficult to organize a structured trial. I get frustrated.
• Timing. I don’t get all of my selections at the same time. They trickle out as they are ready. It is troublesome to drive several hours to a nursery for a few trees knowing that I will have to do it again when the remainder of the order is ready. Not all nurseries deliver or ship.
Budwood. I like seeing the selections launched as soon as possible in the process, but I want a large supply of budwood available at the outset. What is the middle ground here?
Do I have all of my trees? Large growers are frustrated that NVDMC knows what was invoiced and what was paid, but not what was picked up from the nursery. There is no link between NVDMC and the nursery shipment schedule or inventories.

Are you satisfied with the information that you are able to glean from your FAST TRACK plantings, or do you have an expectation data will be collected from and made available from other sources?

Not satisfied: I expect to learn a great deal from my own plantings, but I am seeing issues and I have no way of knowing if I am the only one. Some have seen die-back, apparent rootstock incompatibilities, nutrition issues, chemical sensitivities, etc. Growers want a clearinghouse for information exchange. Some suggested an online forum where growers, breeders, and nurseries can post inquiries and share information. Others prefer a live gathering, while several would rather fill out a written survey.
Fool me once: Those who attended the open grower/nursery discussion on ‘Tango’ and ‘Sugar Belle’ production and packing are not eager to do it again. There were a lot of folks ready to listen and take notes, but not a lot of information was offered. A better mechanism is needed.
Expectation: I fully expect that NVDMC or FFSP or UF/IFAS will be conducting longer-term trials in parallel to the grower program. At some point, the industry will need actionable and published data. I don’t see this coming from the grower trials.

What kind of information would be most helpful?

• Nutrition guidance
• How to get early fruit set
• Fruit quality
• Tree size, health, and yield
• Rootstock guidance
• Pollination information. Is an outside pollen source needed? If so, which ones work best? Will these fruit under screen?

Will the experience and information gleaned from your trial trees be sufficient to support your future planting decisions relative to these selections?

There was no consistency in the answers to this question. Some will base their planting decisions entirely on their own experience; others say a private trial will pique their interest, but more data would be needed in order to support a commercial investment.

From what sources do you seek information about FAST TRACK selections?

By far, the most cited information source is the nursery, followed by other growers, larger formal trials, Extension, and publications.

General comments

• Appreciate the program and raw concept, but it needs fine tuning.
• Can we do this with one nursery? Multiple nurseries decrease the risk but complicates the program.
• Just about all of the new selections are better than what we are currently growing. I am left to balance an inferior known known with a hopefully superior known unknown. Help!
• I have a similar situation with the new oranges. I greatly appreciate that I can get them in the ground now. I plan to trial all that I can get my hands on — but I expect that someone is generating data on these at the same time on some larger scale and that this will be available.


uf_ifas_logoGAINESVILLE, Fla. — About 1.56 million people worked full- or part-time in agriculture, natural resources and food industries in 2014, an increase of about 40,000 workers from 2013, and nearly 29 percent from 2001, according to a new University of Florida Institute of Food and Agricultural Sciences economic report.

Direct employment in the agriculture and natural resources sectors accounted for 13.8 percent of all jobs statewide. Employment in these sectors grew from 1.24 million jobs in 2001 to a peak of 1.34 million in 2008 before the recession, then recovered to 1.56 million in 2014, the latest year for which information is available.

“I would characterize that as modest growth in the industry, although the growth rate was higher before and after the recession (before 2007 and after 2010), and ag-food fared much better during the recession than many other leading industries such as construction and tourism,” said Alan Hodges, Extension scientist with the UF/IFAS food and resource economics department. “Growth in economic activity of agriculture, natural resources and related food industries continues to contribute to the stability of the state’s economy.”

While jobs grew at 2 percent per year, the agricultural inputs and services sectors grew – at a faster rate of 8.2 percent annually. Agriculture, natural resources and their related industries account for $155 billion in sales revenue and contributed $127 billion to state gross domestic product in 2014, the report said.

Hodges sees a bigger picture perspective in the latest results.

“Agriculture and natural resources industries should be viewed in the context of the broader food and fiber economy in which they operate, because value-added processing/manufacturing and distribution activities are the largest sources of jobs and income and are directly tied to other major industries in the state such as tourism,” he said.

Non-food commodity groups such as environmental horticulture and forestry and forest product manufacturing are actually larger than food commodity groups in Florida, he said. Employment reflected that growth.

Employment was highest for the food and fiber commodity groups of environmental horticulture, fruit and vegetable farming/processing, forestry and forest products, livestock and dairy farming and animal products manufacturing, according to the report, which can be found at http://bit.ly/2d5xOLe.

Economic contributions of ag-food industries are greatest in in Florida’s metropolitan areas because of large-scale manufacturing and distribution to the urban population, he said. But basic agricultural commodity production in rural areas and interior counties is more important, relatively speaking, where it represents more than half of all employment and GDP in some areas.