Tag Archive: Citrus

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  

 

PG

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

 

 

PG

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

 

PG

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.

 

PG

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

 

 

PG

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

 

PG

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/

Care of Freeze-Injured Citrus Trees

 

This week, Northwest Florida is once again receiving some bitter cold temperatures. The freezing weather two weeks ago resulted in some cold damage to some local citrus trees. Cold injured citrus trees can take a while to become evident.

Citrus in freezing weather, under protective microsprinkler irrigation. Image Credit Doug Mayo UF IFAS

Citrus in freezing weather, under protective microsprinkler irrigation. Image Credit Doug Mayo UF IFAS

 

What appears to be damage will not always be permanent. Never be in a hurry to remove cold injured tissue from a citrus tree. Citrus, especially Satsuma, can be very resilient and will often re-sprout on injured tissue. Pruning before this can happen can remove fruit producing branches. Leaves on a freeze-damaged citrus tree will be hard and brittle.

If freeze damage is severe, the leaves will collapse, dry out and fall from the tree. It’s normal for leaves to take on a wilted or drooping appearance during periods of low temperatures. Don’t confuse this with freeze damage. Frozen leaves will not be wilted – they will be hard and brittle. Freeze damage can also cause the trunk and larger branches to split and the bark to become loose. Twigs and branches may continue to die for up to two years following a severe freeze.

Unless the soil becomes dry, be careful to not water cold injured citrus trees during warm periods that often follow freezes. This will delay the tree’s growth and keep the tree in a more dormant state. However, it is important to not let citrus trees go totally dry, because this will increase freeze damage. Later on, if you see that the damaged tree is putting on new growth, it’s okay to give it a little water.

It is best to not prune or fertilize citrus trees during fall and winter.Delay pruning of damaged limbs until late spring or summer because it’s difficult to determine the extent of damage until spring growth takes place. Pruning also may encourage new tender growth during the cold season.

If it appears that you’ve lost half the tree in a freeze, you’ll only need to apply about half as much fertilizer. If you have the situation where many leaves were lost but twigs and branches were not injured, you’ll need to slightly increase the amount of fertilizer. Fertilization should begin after new growth has occurred come spring. It’s a good idea to make frequent light applications rather than one heavy application.

Fertilizing your lawn during fall and winter may not only be damaging to your lawn but it can potentially cause cold injury to your citrus trees, as well. The roots on trees (including citrus) extend two to three times beyond the tree’s branches. As a result, citrus tree roots grow out into the lawn. Tree roots in the lawn are shallow. So, late applications of lawn fertilizer will impact your citrus trees as well. Your lawn and citrus needs ample time to use the fertilizer but yet still have time to go dormant before cold weather arrives.

PG

Author: Larry Williams – llw5479@ufl.edu

Larry Williams is the County Extension Director and Residential Horticulture Agent for the UF/IFAS Extension Office in Okaloosa County.

Larry Williams

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2014/01/28/care-of-freeze-injured-citrus-trees/

Citrus Canker Found in Northwest Florida

Citrus Canker Found in Northwest Florida

2013-11-21 Citruscanker_SR_clusterleaves_lesions

Citrus Canker lesions on leaves. Photo Credit: Beth Bolles, UF IFAS Extension – Escambia County

Authors: Blake Thaxton & Mary Derrick, UF/IFAS Extension – Santa Rosa Co. Mikaela Anderson, FDACS Division of Plant Inspection

Citrus canker is a serious disease of citrus trees that was recently confirmed for the first time in southern Santa Rosa County. Canker is caused by the bacterial pathogen Xanthomonas citri subsp. citri.  Citrus canker has been a major pest of citrus in south and central Florida. It is economically damaging to the commercial industry and is also problematic to homeowners because it causes premature fruit drop, discolored fruit, and eventually causes the tree to become unproductive.

Canker was first introduced in 1912 into Florida and was declared eradicated in 1933. The disease was found again in the Tampa area on citrus in 1986.  It was declared eradicated in 1994, but once again was found in 1995 in Miami.  This time, the disease was not successfully eradicated in part because hurricanes made the disease too widespread to control. Despite its prevalence in south and central Florida, this disease has not been known in the Panhandle. The University of Florida and the Florida Department of Agriculture and Consumer Services’ Division of Plant Industry will be assessing the extent of the disease in Santa Rosa County in the coming months.

2013-11-21 citruscanker_SR_leafminer_lesions

Lesions growing through the channels formed by the Citrus Leafminer insect. Photo Credit: Beth Bolles, UF IFAS Extension – Escambia County

How might you know if your citrus is infected by canker?  One of the best indicators of canker is the presence of lesions, diseased spots, on the upper and lower surfaces of the leaves.  The lesions will be raised and have a rough surface and will be surrounded by yellow halos. Similar lesions may be present on the fruit and stems as well.

Important!

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

2013-11-21 Citruscanker_SR_Stemlesion

Lesions formed on the stems. Photo Credit: Beth Bolles, UF IFAS Escambia County Extension

The disease is highly contagious to citrus only and spreads rapidly through wind, rain and via people on their hands, clothes, and tools.  Do not transport any plant material that shows symptoms of canker.  Decontamination practices should be used when going from one citrus tree to the next.  Hand washing with soap and water for 20 seconds or more to eliminate bacterium on the skin should be practiced as well as using alcohol-based hand sanitizer.  Pruning tools or other tools that come into contact with citrus should be disinfected by a fresh solution of 1 ounce of household bleach to 1 gallon of water.  An old or dirty bleach solution is not able to disinfect because the chemical is no longer active.

Warning!

Do Not Move a Plant Infected with Citrus Canker.  Please Call your local Extension Office for further instructions

 

For more information on citrus canker:

              (The University of Florida IFAS Citrus Canker website provides a photo gallery of disease symptoms & information about the disease)

PG

Author: Blake Thaxton – bthaxton@ufl.edu

Santa Rosa County Extension
Agent I, Commercial Horticulture

Blake Thaxton

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2013/11/25/citrus-canker-found-in-northwest-florida-2/

Citrus Canker found in Northwest Florida

Citrus Canker found in Northwest Florida

2013-11-21 Citruscanker_SR_clusterleaves_lesions

Citrus Canker lesions on leaves.  Photo Credit: Beth Bolles, UF/IFAS Extension – Escambia County

Blake Thaxton & Mary Derrick, UF/IFAS Extension – Santa Rosa Co.
Mikaela Anderson, FDACS Division of Plant Inspection

Citrus canker is a serious disease of citrus trees that was recently confirmed for the first time in southern Santa Rosa County. Canker is caused by the bacterial pathogen Xanthomonas citri subsp. citri.  Citrus canker has been a major pest of citrus in south and central Florida. It is economically damaging to the commercial industry and is also problematic to homeowners because it causes premature fruit drop, discolored fruit, and eventually causes the tree to become unproductive.

Canker was first introduced in 1912 into Florida and was declared eradicated in 1933. The disease was found again in the Tampa area on citrus in 1986.  It was declared eradicated in 1994, but once again was found in 1995 in Miami.  This time, the disease was not successfully eradicated in part because hurricanes made the disease too widespread to control. Despite its prevalence in south and central Florida, this disease has not been known in the Panhandle. The University of Florida and the Florida Department of of Agriculture and Consumer Services’ Division of Plant Industry will be assessing the extent of the disease in Santa Rosa County in the coming months.

Lesions growing through the channels formed by the Citrus Leafminer insect.

Lesions growing through the channels formed by the Citrus Leafminer insect. Photo Credit: Beth Bolles, UF/IFAS Extension – Escambia County

How might you know if your citrus is infected by canker?  One of the best indicators of canker is presence of lesions, diseased spots, on the upper and lower surfaces of the leaves.  The lesions will be raised and have a rough surface and will be surrounded by yellow halos. Similar lesions may be present on the fruit and stems as well.

Important!

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

Lesions formed on the twigs.

Lesions formed on the stems. Photo Credit: Beth Bolles, UF/IFAS Escambia County Extension

The disease is highly contagious to citrus only and spreads rapidly through wind, rain and via people on their hands, clothes, and tools.  Do not transport any plant material that shows symptoms of canker.  Decontamination practices should be used when going from one citrus tree to the next.  Hand washing with soap and water for 20 seconds or more to eliminate bacterium on the skin should be practiced as well as using alcohol-based hand sanitizers.  Pruning tools or other tools that come into contact with citrus should be disinfected by a fresh solution of 1 ounce of household bleach to 1 gallon of water.  An old or dirty bleach solution is not able to disinfect because the chemical is no longer active.

Warning!

Do Not Move a Plant Infected with Citrus Canker.  Please Call your local Extension Office for further instructions

 

For more information on citrus canker:

              (The UF Canker website provides a photo gallery of disease symptoms & information about the diesease)

 

 

PG

Author: Blake Thaxton – bthaxton@ufl.edu

Santa Rosa County Extension
Agent I, Commercial Horticulture

Blake Thaxton

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2013/11/23/citrus-canker-found-in-northwest-florida/

Older posts «