Tag Archive: Citrus

Friday Feature: Hurricane Irma’s Impact on the Florida Citrus Industry Video

Friday Feature:  Hurricane Irma’s Impact on the Florida Citrus Industry Video

Citrus trees in Hendry County destroyed by Hurricane Irma. Credit: Gene McAvoy

This week’s featured video was a CBS News report on the damage from Hurricane Irma to Citrus in Southwest Florida.  The story features Paul Meador, Citrus Grower and Gene McAvoy, UF/IFAS Regional Vegetable Agent, who were out earlier this week assessing damage to crops and citrus in Hendry County.  McAvoy estimates there were more than $ 2 billion dollars in damages in Southwest Florida where the eye-wall of Hurricane Irma churned up groves, ranches, and vegetable farms.

 

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If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across a humorous video or interesting story related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo

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Author: Doug Mayo – demayo@ufl.edu

Lead Editor for Panhandle Ag e-news – Jackson County Extension Director – Livestock & Forages Agent. My true expertise is with beef cattle and pasture management, but I can assist with information on other livestock species, as well as recreational fish ponds.
http://jackson.ifas.ufl.edu

Doug Mayo

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/09/15/friday-feature-hurricane-irmas-impact-on-the-florida-citrus-industry-video/

A Tiny Wasp to Fight the Asian Citrus Psyllid

A Tiny Wasp to Fight the Asian Citrus Psyllid

Fig. 1 Asian citrus psyllid nymphs. Photo by Lyle Buss UF/IFAS Department of Entomology and Nematology

The Asian citrus psyllid (Fig 1), the carrier of the causative agent of citrus greening or Huanglongbing (HLB), is certainly the most devastating pest in citrus worldwide. Since it was first spotted in Florida in 1998, the Asian citrus psyllid has spread across the state, and starting in 2005, the first cases of HLB were detected in Florida. Since then, HLB and the Asian citrus psyllid quickly became established throughout the state in all citrus production areas.  The disease has a disastrous impact on citrus production by decreasing yields, lowering fruit quality, and killing trees a few years after pathogen infection.

Fig. 2. Population of Asian citrus psyllid during spring 2017 in Franklin County. (A) Number of nymphs per flush of new leaves, (B) number of adult psyllids found on citrus trees after 8 min of observation.

Until recently, the Asian citrus psyllid was only found occasionally in the Florida panhandle.  This summer, however, Asian citrus psyllids were found in four panhandle counties – Gulf, Bay, Franklin, and Suwannee Counties. So far in the panhandle, Asian citrus psyllid have only been found in backyard gardens, but the population along the coast has been high enough to warrant a responsive action (Fig. 2).

Fig. 3 The wasp Tamarexia radiata is a parasitoid of the Asian citrus psyllid. Photo by Lyle Buss

In partnership with local growers and Dr. Kerr from the Florida Department of Agriculture and Consumer Service (FDACS), a biological agent was released in Franklin and Suwannee Counties to fight the recent infestation of the Asian citrus psyllid. This tiny wasp called Tamarixia radiata (Fig. 3) only attacks the Asian citrus psyllid, and will find its host by following attractive odors emitted by the citrus plant and by chemical cues emitted directly by psyllid nymphs. The female wasp will lay eggs on the ventral (under) side of 3rd to 5th instar psyllid nymphs. The parasitoid larvae then grow and develop by sucking the hemolymph (fluid equivalent to blood in most invertebrates), from their host, and eventually emerge as an adult through a small hole on the thorax of the dead psyllid (Fig 4). In addition, the female wasps also feed directly on psyllid nymphs; therefore this wasp controls psyllids by both parasitism and predation.

Fig. 4: Asian citrus nymphs with a hole on their thorax where a wasp emerged. Photo by Dr. Michael Roger UF/IFAS Citrus Research and Education

Interestingly, the FDACS has developed a biological control program to release the wasp across Florida, and homeowners interested can contact FDACS to request free delivery of the wasp.  This could be particularly useful in cases where Asian citrus psyllid infestations occur and insecticide spray is not possible or not desired. It is important that the parasitic wasp is released outside of any insecticidal spray to minimize mortality, and in the presence of psyllid nymphs as this is the only stage attacked by the wasp.

Another important aspect to consider is the presence of ants. Ants feed on honeydew secreted by psyllid nymphs and will protect them from predator and parasitoids.  Presence of ants can decrease efficiency of Tamarixia radiata biocontrol by 85%!  Therefore, to obtain optimal control of Asian citrus psyllid by the wasp it is recommended to keep ants under control.  This can be accomplished, for example, by smearing a 2-cm wide barrier of sticky Tangelfoot or other non-insecticidal barrier at the base of the trunk to exclude ants from the citrus tree.

The parasitic wasp, Tamarixia radiate, is an important tool to control the Asian citrus psyllid.  It is important to keep in mind, however, that while this biological control can lower the numbers of Asian citrus psyllid, it cannot completely eradicate this pest.  Even though this biological control will not eradicate psyllids, it can lower the risk of having psyllids invading citrus groves in the panhandle.  Management recommendations for citrus growers in the panhandle include routine and thorough scouting for psyllids by examining the trees, especially newly flushed leaves, and using yellow sticky traps in their groves.

Further information on this topic can be found at the following sites:

FDACSAsian Citrus Psyllid Biological Control

FDACS – Tamarixia Release Application

UF/IFAS Featured Creatures – Asian citrus psyllid

UF/IFAS Featured Creatures – Asian citrus psyllid parasitoid –Tamarixia radiata

 

 

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Author: Xavier Martini – xmartini@ufl.edu

Xavier Martini is Assistant Professor of Entomology at the University of Florida, NFREC.

Xavier Martini

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/07/14/a-tiny-wasp-to-fight-the-asian-citrus-psyllid/

Citrus Greening Confirmed in Alabama

Citrus Greening Confirmed in Alabama

Citrus Greening. Photo Credit: Mongi Zekri, UF/IFAS.

Amy Belcher, Alabama Department of Agriculture and Industries

A plant disease that presents a serious threat to the U.S. citrus industry has been detected in Alabama. Federal and state plant health officials have confirmed the identification of Citrus Greening (CG), also known as Huanglongbing or HLB, which is caused by the bacterial pathogen Candidatus Liberibacter asiaticus.

This is the first confirmation of citrus greening in Alabama, despite biannual surveys for the pathogen by the Alabama Department of Agriculture and Industries (ADAI). The ADAI, along with the USDA Animal Plant Health Inspection Service (APHIS) and the U.S. Department of Homeland Security Customs and Border Protection (CBP), will be conducting a delimiting survey to determine the extent that the pathogen may have spread.  If the disease is limited to only a few trees, steps will be taken to eradicate the disease.

Citrus greening was found in leaf and insect samples from a residential property on Dauphin Island in Mobile County. ADAI officials have devised a plan of action.  Surveillance teams will take additional samples for testing, survey the area around the site, and gather data on the tree’s history, if possible. The delimiting survey will begin June 26, 2017, and should conclude by the end of the week. The citrus survey set to take place that week in the Wiregrass region will be postponed until the week of July 10th. Outreach and education to nurseries, plant dealers, and citrus hobbyists will be conducted concerning citrus greening in the near future as well.

Other than tree removal, there is no known cure or effective control for the disease once a tree is infected. Citrus greening reduces the quantity and quality of citrus fruits, eventually rendering infected trees useless. In areas of the world affected by citrus greening the average productive lifespan of citrus trees has dropped from 50 or more years to 15 or less. An infected tree declines and dies within 3 to 5 years.  Before its eventual death, the tree produces fruit that is bitter and unusable and serves as a source of infection for other citrus trees in the surrounding area.

Adult Asian citrus psyllid. UF/IFAS File Photo.

In our neighboring state of Florida, the citrus industry has been significantly affected by the rapid spread of citrus greening. According to a study conducted by University of Florida’s Institute of Food and Agricultural Sciences Extension, since the first detection of citrus greening in Florida in 2005, orange acreage has been reduced by 26% and yield has decreased by 42%. Orange production dropped from 242 million boxes to 104.6 million boxes in 2014. Overall the impact on the citrus industry has been devastating.

The disease-causing bacteria are spread by the Asian citrus psyllid (ACP). The insect was found in Baldwin County, Alabama in 2008, but no citrus greening bacteria was detected, even though molecular analysis of insects collected in the area was conducted.  The discovery of psyllids in 2008 led to federal and state ACP quarantines of the entire State of Alabama in 2009.

Officials have begun the process to halt the movement of citrus plants from the area. With the confirmation of citrus greening in Dauphin Island, federal plant officials will seek to establish a citrus greening quarantine in Mobile County.  Alabama agriculture officials have indicated that the state intends to take action to establish a parallel quarantine. The dual action makes it possible for federal regulators to hold the quarantine for CG only for those counties in Alabama in which the disease is present.

Citrus greening has been in Asia and Africa for decades. It was detected in Brazil in 2004 and Florida in 2005. For more information about citrus greening or questions about the delimiting survey, please contact Christel Harden by email at Christel.Harden@agi.alabama.gov or by phone at 334-240-7226.

 

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Author: admin – webmaster@ifas.ufl.edu

admin

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/07/03/citrus-greening-confirmed-in-alabama/

Citrus Canker in Northwest Florida

Citrus Canker in Northwest Florida

Citrus canker symptoms on twigs, leaves and fruit. Photo by Timothy Schubert, FDACS

In November 2013, citrus canker was found for the first time in the Florida panhandle in Gulf Breeze in southern Santa Rosa County. The Florida Department of Agriculture and Consumer Services (FDACS) tested and confirmed the disease on grapefruit trees in a residential landscape. Since that time, citrus canker has been confirmed on citrus trees at 27 more locations in Gulf Breeze. To my knowledge it has not been found in any other location in the panhandle. Not yet.

Citrus canker lesions on leaves are raised, rough and visible on both sides of the leaf. Photo by Timothy Shubert, FDACS.

Citrus canker is a serious bacterial disease that only infects citrus trees. It will not infect any other plant species nor is it a threat to human health. This highly contagious disease has no cure as yet. Severely affected trees experience substantial leaf and premature fruit drop and serve as a source for infecting other citrus in the area. The disease spreads through wind, rain and transportation of infected plant material from other locations.

We do not know how the disease came to infect trees in our region. The disease could have been spread through infected fruit or trees brought here from areas where the disease is established, such as central or south Florida.

What should you do if you suspect your citrus is infected with this disease?

Citrus canker lesions can appear in the mines left by the citrus leafminer pest. Photo by Timothy Schubert, FDACS

  1. Look at Homeowner Fact Sheet: Citrus Canker for more information.
  2. Leave the tree in place in your yard and call the Division of Plant Industry at FDACS at 1-888-397-1517 for a free inspection and testing of your citrus trees.
  3. Consult your local Horticulture Extension Agent for more information and control/removal strategies.
  4. Proper removal of infected trees is recommended to prevent the spread of citrus canker but is not mandatory.

 

For more information please see:

Save Our Citrus Website

UF IFAS Gardening Solutions: Citrus

Citrus Culture in the Home Landscape

UF IFAS Extension Online Guide to Citrus Diseases  

 

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Author: Mary Derrick – mderrick@ufl.edu

Residential Horticulture Extension Agent for Santa Rosa County

Mary Derrick

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/05/12/citrus-canker-in-northwest-florida/

Citrus Greening (HLB) A Troublesome Bacterial Pathogen

Citrus Greening (HLB) A Troublesome Bacterial Pathogen

Small Fruit vs Normal

If we look at the big picture when it comes to invasive species, some of the smallest organisms on the planet should pop right into focus. A microscopic bacterium named Candidatus Liberibacter asiaticus, the cause of Citrus Greening (HLB), has devastated the citrus industry worldwide. This tiny creature lives and multiplies within the phloem tissue of susceptible plants. From the leaves to the roots, damage is caused by an interruption in the flow of food produced through photosynthesis. Infected trees show a significant reduction in root mass even before the canopy thins dramatically. The leaves eventually exhibit a blotchy, yellow mottle that usually looks different from the more symmetrical chlorotic pattern caused by soil nutrient deficiencies.

One of the primary vectors for the spread of HLB is an insect called the Asian citrus psyllid. These insects feed by sucking juices from the plant tissues and can then transfer bacteria from one tree to another. HLB has been spread through the use of infected bud wood during grafting operations also. One of the challenges with battling this invasive bacterium is that plants don’t generally show noticeable symptoms for perhaps 3 years or even longer. As you would guess, if the psyllids are present they will be spreading the disease during this time. Strategies to combat the impacts of this industry-crippling disease have involved spraying to reduce the psyllid population, actual tree removal and replacement with healthy trees, and cooperative efforts between growers in citrus producing areas. You can imagine that if you were trying to manage this issue and your neighbor grower was not, long-term effectiveness of your efforts would be much diminished. Production costs to fight citrus greening in Florida have increased by 107% over the past 10 years and 20% of the citrus producing land in the state has been abandoned for citrus.

Classic blotchy mottle in Leaves

Many scientists and citrus lovers had hopes at one time that the Florida Panhandle would be protected by our cooler climate, but HLB has now been confirmed in more than one location in backyard trees in Franklin County. The presence of an established population of psyllids has yet to be determined, as there is a possibility infected trees were brought in.

A team of plant pathologists, entomologists, and horticulturists at the University of Florida’s centers in Quincy and Lake Alfred and extension agents in the panhandle are now considering this new finding of HLB to help devise the most effective management strategies to combat this tiny invader in North Florida. With no silver-bullet-cure in sight, cooperative efforts by those affected are the best management practice for all concerned. Vigilance is also important. If you want to learn more about HLB and other invasive species contact your local UF/IFAS Extension office.

Asymmetrical Fruit

 

 

 

 

 

 

 

 

 

 

Typical nutrient deficiencies observed in leaf, on trees with heavy fruit load. Not related to Citrus Greening (HLB)

 

Article by: Erik Lovestrand, UF/IFAS Franklin County Extension Director/Florida Sea Grant Agent

 

 

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Author: admin – webmaster@ifas.ufl.edu

admin

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/03/02/citrus-greening-hlb-a-troublesome-bacterial-pathogen/

Dooryard Citrus Care for February

Dooryard Citrus Care for February

Dooryard citrus enthusiasts may be uncertain about late winter management of Satsuma and other citrus trees.  Several questions that have come in to the Extension Office recently include:

  • Should I prune my trees?
  • Why are the leaves yellow?
  • How soon should I fertilize? 

The focus of this article is to provide some answers to these common questions.

Should I prune my trees?

This is a complicated question that is best answered with “it depends…”  Pruning is not necessary for citrus, as it is in many temperate fruits, to have excellent production quality and quantity. Citrus trees perform excellently with minimal pruning. The only pruning necessary for most citrus is removing crossing or rubbing branches while shaping young trees, removing dead wood, and pruning out suckers from the root-stock. Homeowners may choose to prune citrus trees to keep them small, but this will reduce potential yield, since bigger trees produce more fruit.

Often, maturing Satsuma trees produce long vertical branches. It is tempting to prune these off, since they make the tree look unbalanced. To maximize yield, allow these branches to weep with the heavy load of fruit until they touch the ground. This allows increased surface area for the tree, since the low areas around the trunk are not bare. Additionally, weeds are suppressed since the low branches shade out weed growth. The ground under the trees remains bare, thus allowing heat from the soil to radiate up during cold weather events. The extra branches around the trunk offer added protection to the bud union as well. If smaller trees are desired for ease of harvest, ‘flying dragon’ root-stock offers dwarfing benefits, so that the mature scion cultivar size will only grow to 8-10 feet tall.

Heavy fruit loads were produced in many home gardens throughout Northwest Florida last year. When fruiting is heavy, citrus trees translocate nitrogen and other nutrients from older leaves to newer growth and fruit. Therefore, temporary yellowing may occur and last until trees resume growing in the spring. Remember, never fertilize after early September, since fertilizing this late in the year  can reduce fruit quality and increase potential for cold injury. If a deficiency, as in the photo above persists through spring, consider a soil test, or consult a citrus production publication to determine if additional fertilizer should be added to your fertilizer program.

How soon should you fertilize?

Although most Florida citrus publications recommend fertilizing citrus in February, they don’t take into account the potential for late frost in the Panhandle. Thus it makes more sense to wait until mid-March for the first fertilizer application in this region. Citrus trees don’t require a fertilizer with a high percentage of nitrogen, so it is best for fruit quality if an analysis of around 8-8-8 with micro-nutrients is used. Fertilizer should be applied in the drip-line of the tree, not around the trunk. The drip-line of a mature tree is generally considered to extend one foot from the trunk out to one foot from the edge of the furthest branch tip from the trunk. For fertilizer quantity recommendation see the chart below.

Table edited by Doug Mayo, from “Citrus Culture in the Home Landscape”

Through awareness of the unique managements techniques inherent to  dooryard citrus production in the Panhandle, home gardeners are offered an opportunity to provide their friends and family with a substantial portion of their annual citrus !

 

For more information on this topic please use the following link to the UF/IFAS Publication:

Citrus Culture in the Home Landscape

 

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Author: Matthew Orwat – mjorwat@ufl.edu

Matthew J. Orwat started his career with UF / IFAS in 2011 and is the Horticulture Extension Agent for Washington County Florida. His goal is to provide educational programming to meet the diverse needs of and provide solutions for homeowners and small farmers with ornamental, turf, fruit and vegetable gardening objectives. Please feel free to contact him with any questions you may have.
http://washington.ifas.ufl.edu/lng/about/

Matthew Orwat

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/02/14/dooryard-citrus-care-for-february/

Panhandle Citrus Producers Need to Symptoms of Canker and Greening

Panhandle Citrus Producers Need to Symptoms of Canker and Greening

Florida’s citrus producers, as well as backyard growers have battled detrimental issues like hard freezes and storm damage over the years.  However, in recent years, emergent bacterial diseases known as citrus canker and citrus greening have been devastating Florida’s citrus crops.  Although these diseases are not yet a major issue in the Panhandle, it’s important to be aware of the characteristics of these diseases.

Citrus Canker

In 2013, the first case of citrus canker in the Florida Panhandle was found in southern Santa Rosa County. Citrus canker is usually produced under moist conditions and easily dispersed by windblown rains. The bacterium either enters through the leaves or fruit, especially through a wound.  Damage from the citrus leafminer is a notorious origin of the disease. Symptoms will appear as tiny blisters on both sides of the leaves. As time goes on, the blister will turn into pronounced, raised brown rings. In severe cases, the condition can appear on stems and fruit (Figure 1).

citrus_canker

Figure 1: Citrus Canker. Photo Credit: Mongi Zekri, UF/IFAS.

Citrus canker can be spread by contact with clothes and pruning equipment, so its important to sanitize field equipment after any thought of possible contact. There is limited chemical control for citrus canker, but a copper compound fungicide will help stifle the condition.

Citrus Greening

Another condition known as citrus greening or HLB (Huanglongbing), is particularly a menace to citrus groves in South Florida. Citrus greening is caused by an insect known as the Asian citrus psyllid. In 1998, the insect was found in a few counties on the east coast of Florida. By 2001, the insect had been found in 31 counties, nearly half the state.

Citrus greening works a bit differently than citrus canker. As the psyllid feeds on the leaves of the tree, the bacterium is released. The bacterium lives and thrives in the tree’s phloem. The phloem is the living tissue of the tree that transports nutrients throughout. Unfortunately, once infected, the tree will steadily decline in health. Fruit production will drop in number, size and taste each year until the demise of the tree. Sadly, there are no commercially avaiable citrus species that are immune to the bacterium.

Symptoms of citrus greening often begin by the yellowing of the leaves along the veins. A green tie-dye look to the leaves is a typical sign (Figure 2). To make matters worse, it’s difficult to diagnose. These symptoms can easily be confused with nutrient deficiency. Lab analysis is required for accurate identification. There are no chemical treatment options either, only methods to keep the condition from spreading. A non-systemic pesticide like malathion or neem oil, a less toxic repellent, can help combat the spread of the disease.

Figure 2: Citrus Greening. Photo Credit: Mongi Zekri, UF/IFAS.

Figure 2: Citrus Greening. Photo Credit: Mongi Zekri, UF/IFAS.

Citrus canker and citrus greening are serious diseases that threaten Florida’s citrus crop. Controlling the source of the bacterium is extremely important. Keep in mind that the most common vector regarding the spread of these diseases is humans transferring citrus from one region to another.

Important!

If you suspect that your citrus trees may have either condition, please contact the FDACS Division of Plant Industry’s Helpline Center at 1-888-397-1517 before taking any action to reduce accidental spread of this disease. 

 

For more information, please visit the UF Citrus Research and Education Center website, or contact your local county extension office.

 

Supporting information for this article can be found in the UF/IFAS EDIS publications:

 

An Equal Opportunity Institution. UF/IFAS Extension, University of Florida, Institute of Food and Agricultural Sciences, Nick T. Place, Dean for UF/IFAS Extension. Single copies of UF/IFAS Extension publications (excluding 4-H and youth publications) are available free to Florida residents from county UF/IFAS Extension offices.

 

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Author: Ray Bodrey – rbodrey@ufl.edu

Gulf County Extension Director, Agent II Agriculture, Natural Resource & Community Development

Ray Bodrey

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2016/08/06/panhandle-citrus-producers-need-to-symptoms-of-canker-and-greening/

Citrus Choices for the Panhandle

Citrus Choices for the Panhandle

The panhandle of Florida is a great place to grow citrus with our plentiful sunshine and sandy soil. But some varieties do better than others. Here are some that thrive in the more northerly climes of Florida:

Nagami kumquat. Photo credit: UF/IFAS.

Nagami kumquat. Photo credit: UF/IFAS.

  • Satsuma mandarin is cold hardy to 15°F once established. There are a few different available cultivars with fruit ripening October through December. Fruit needs to be picked promptly when ripe.
  • Kumquat is cold hardy to 10°F once established. ‘Nagami’ and ‘Meiwa’ are the two common cultivars of the small tart fruits. Fruit matures in fall and winter and holds fairly well on the trees.
  • Calamondin is a lesser known variety that bears small fruit that resemble tangerines. The tart fruit is great for jams and chutneys. Fruit is borne all year.
  • Some of the sweet oranges that do well in the panhandle are Navel, Hamlin and Parson Brown. They are cold hardy to 14°F once established and are harvested November through January.
  • Minneola or Honeybell tangelo is also hardy to 14°F and harvested in January. This is a cross between a Duncan grapefruit and a Darcy tangerine. This bell-shaped fruit is very juicy and sweet. Unlike the other citrus varieties, it needs another citrus nearby for cross-pollination in order to produce an abundant crop.
  • Meyer Lemon is the choice to make if you would like to grow lemons in the panhandle. Other lemons may be damaged by our occasional freezes.

Grapefruit and lime can be grown – although unreliably – on the coast with protection from northwestern winter winds. They are much more susceptible to freezes in more northerly panhandle locations.

In order to have the healthiest and most productive trees, learn about how to properly care for citrus and how to recognize and combat the pests and diseases that occur.

Citrus canker symptoms on leaves, fruit and stem. Photo by Timothy Schubert, FDACS

Citrus canker symptoms on leaves, fruit and stem. Photo by Timothy Schubert, FDACS

There are threats to our dooryard and commercial citrus from pests and disease. Only vigilance will help to combat the challenges so that we may continue to grow and enjoy our citrus. What can we do to protect our citrus?

  • Report any serious diseases like suspected citrus canker or citrus greening to the Division of Plant Industry by calling toll-free 1-888-397-1517. Inspections and diagnosis are free. Citrus canker has been confirmed in south Santa Rosa County in the past 3 years.
  • Purchase citrus trees only from registered nurseries – they may cost a little more but they have gone through an extensive process to remain disease and pest free. That will save you $ $ in the long run!
  • Don’t bring plants or fruit back into Florida – they may be harboring a pest!
  • Citrus trees or fruit cannot move in or out of the State of Florida without a permit. This applies to homeowners as well as to the industry. This rule protects our vital dooryard trees and citrus industry.

For more information please see:

Save Our Citrus Website

UF IFAS Gardening Solutions: Citrus

Citrus Culture in the Home Landscape

UF IFAS Extension Online Guide to Citrus Diseases  

Your Florida Dooryard Citrus Guide – Common Pests, Disease and Disorders of Dooryard Citrus

 

 

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Author: Mary Derrick – mderrick@ufl.edu

Residential Horticulture Extension Agent for Santa Rosa County

Mary Derrick

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2016/05/06/citrus-choices-for-the-panhandle/

Start Fertilizing Citrus in February

Start Fertilizing Citrus in February

As you have read in other articles in this blog, it is too early to fertilize your lawn; however, this is a good time to start fertilizing your citrus to ensure a healthy fruit crop later in the year.

Orange grove at the University of Florida. UF/IFAS photo by Tara Piasio.

Orange grove at the University of Florida. UF/IFAS photo by Tara Piasio.

Citrus benefits from regular fertilization with a good quality balanced citrus fertilizer that also contains micronutrients. A balanced fertilizer has equal amounts of nitrogen, phosphorus and potassium such as a 6-6-6, 8-8-8 or a 10-10-10. The amount of fertilizer to be applied will vary on the formulation; for example you will need less of a 10-10-10 than a 6-6-6 as the product is more concentrated. Always consult the product label for the correct amount to use for your particular trees. Fertilizer spikes are not recommended as the nutrients are concentrated in small areas and not able to be widely available to all plant roots.

The number of fertilizations per year will vary depending on the age of the tree. Trees planted the first year need 6 light fertilizations that year starting in February with the last application in October. In following years, decrease the number of fertilizations by one per year until the fifth year when it is down to 3 fertilizations per year. From then on, keep fertilizing 3 times per year for the life of the tree. Good quality citrus fertilizer will have accurate and specific instructions on the label for the amount and timing of fertilizer application.

Fertilizer should be spread evenly under the tree but not in contact with the trunk of the tree. Ideally, the area under the drip line of the tree should be free of grass, weeds and mulch in order for rain, irrigation and fertilizer to reach the roots of the tree and provide air movement around the base of the trunk.

If you have not in recent years, obtain a soil test from your local extension office. This can detect nutrient deficiencies, which may be corrected with additional targeted nutrient applications.

For more information:

Citrus Culture in the Landscape

 

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Author: Mary Derrick – mderrick@ufl.edu

Residential Horticulture Extension Agent for Santa Rosa County

Mary Derrick

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2016/02/16/start-fertilizing-citrus-in-february/

Fruit Splitting in Dooryard Citrus

Fruit Splitting in Dooryard Citrus

Split citrus fruit. Image credit UF / IFAS

Split citrus fruit. Image credit UF / IFAS

Citrus trees require a lot of care and attention to produce good quality fruit, yet even the most careful gardeners may run into the problem of split-fruit on their citrus trees.  Split-fruit is a condition which strikes citrus trees in September and October and can wipe out a hundred or more fruit on a single tree.  Researchers at the University of Florida have been studying fruit splitting for many years.  Clear cut causes or solutions have not been found.  My information on fruit splitting was provided by Extension Fruit Crop Specialist, Dr. Pete Andersen with IFAS located at Quincy, North Florida Research and Education Center.

Researchers have found that certain varieties of citrus tend to split more often than other.  “Sweet Oranges” Tangelos” and certain varieties of Satsuma’s tend to split more than citrus which is not sweet.  Grapefruit and acid fruits, such as lemons and limes rarely split.

The condition is known to be more common in seedlings and young trees than in older, more settled trees.  However, split-fruit can be a very serious problem when it occurs on mature trees, because they usually have more fruit to lose.

Another condition which will cause fruit to split is insufficient copper in the soil.  This used to be a much greater problem than it is today, due to the wide-spread use of copper in most fertilizer and spray programs.  Potassium deficiency results in small, firm fruit with thin peels and increased fruit splitting.  However, added potassium doesn’t correct splitting related to citrus varieties.

The most commonly held belief is that fruit splitting is caused by climatic conditions, since it only seems to occur at one time of the year.  During the late summer and high humidity, followed by periods of drought.  After a series of heavy rains, the trees absorb a great deal of moisture and force it into the fruit.  Since the fruit is near maturity, the rind becomes less pliable and can’t expand rapidly enough to absorb the great volume of water from the trees.  As a result the fruit splits.

Despite these findings, there are numerous cases of fruit splitting that doesn’t appear to be related to any of the above conditions.  When the cause of the split is not fully understood, there is not absolute method of control.  Also, there is no way to stop fruit splitting while it is occurring.  The problem must be prevented before it starts.  Attempts to control splitting through irrigation practices, fertilization and growth regulators have met with some success.

Fertilizer and irrigation practices won’t cure splitting, but may help to avoid large increase in the number of split fruit.  In addition, growth regulators are available which can thicken the peel of the orange.  Thicker peels have been found to split much less often that the thinner peels, due to their ability to withstand extra water pressure during the critical moths of the year.

If fruit splitting is a problem this year follow a recommended fertilizer program next year.  This will insure a good supply of minor nutrients, especially copper.  Make sure to keep the trees well watered during the dry periods of late summer and early fall.  This will keep the fruit from swelling too rapidly, and splitting as a result.

 

PG

Author: Roy Carter – rlcarter@ufl.edu

Roy Carter

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2014/10/28/fruit-splitting-in-dooryard-citrus/

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