Leaf curl on citrus

Curled Leaves On Citrus Plant: What To Do For Curling Citrus Leaves

Citrus plants are bright, fun additions to the patio or landscape (and even indoors), providing a gardener with a steady supply of sweet and tart fruits with little regular care. As far as fruit trees go, citrus tend to be the low-fuss member of the team; but when curling citrus leaves appear, you’ll need to intervene. Curled leaves on citrus plants may indicate a significant pest problem or can point to an environmental issue.

What Causes Citrus Leaf Curl?

Citrus leaf curl is caused by many different things, making positive identification of your problem important before you can determine how to treat leaf curling on citrus. Below are the most common causes of curling citrus, along with ways to manage them.

Sap-sucking pests like aphids, mites and psyllids feed on citrus leaves by extracting the juices directly from transport tissues. As populations grow, they can cause deformations including curling and cupping in leaves, as well as discoloration. When you notice your citrus leaves are curling, check their undersides carefully for tiny pests feeding in clusters. If you spot them, spray your citrus tree with insecticidal soap or neem oil, making sure to coat areas where pests were spotted. Repeat this treatment weekly until your citrus plant begins to recover and all signs of insects are gone.

Citrus leaf miners are another insect pest of citrus, but instead of sucking on leaf juices, the moth larvae tunnel through leaf tissues as they grow. These tunnels are highly visible on leaf surfaces, appearing as undulating white or yellow lines on the green leaf surfaces. Citrus leaf miners are difficult to treat successfully; it’s generally recommended that you allow them to run their course since most citrus trees can tolerate a significant leaf miner load.

Environmental issues

Drought stress is the most common cause of leaf curl in citrus, but also the easiest to remedy. If leaves begin to curl inward while retaining their green coloration and the soil around your tree feels dry to the touch, you’re not watering enough. Stepping up watering efforts and applying 2 to 4 inches of an organic mulch to the ground around your citrus plant will help it recover. Wait to fertilize until the tree resumes normal, healthy leaf production.

Potassium deficiencies show up in citrus as leaves with a yellow cast that are bent downward at the tip. Check the soil pH and nutrient levels before fertilizing these trees to ensure there aren’t bigger problems. If everything checks out, supplement with an extra dose of fertilizer and monitor your tree for improvement. Make sure to provide the tree with enough water to move potassium throughout its system.

Why Are Leaves Curling on My Orange and Lemon Trees?

Why Are Leaves Curling on My Orange and Lemon Trees?

Curling leaves are common on citrus trees and may result from one or more causes. Here are a five of the most-common:

Drought Stress: Insufficient soil water is probably the most-common general cause of curling citrus leaves. This can occur at any time of year, but is most common with trees in areas that aren’t regularly irrigated, during long periods without rainfail, and during hot weather. The upper left of the picture above shows leaf curl typical of drought stress. Water slowly and deeply at the driplines of the trees (on the surface of the ground below the edges of the canopy), preferably using chlorine-free water. Mature citrus trees in dry soil may need 12 hours or more of watering with a hose on a slow trickle at one or more locations around the trees to resolve drought stress. An organic mulch may help retain soil moisture and improve soil over time. Cover most of the soil surface under citrus trees with up to 2 inches of coarse mulch, extending past the driplines, but avoid placing mulch within a foot of the trunk of mature trees, and keep mulch several inches away from major surface roots.

Cold Weather: Citrus leaves may curl in response to cold weather. Many types of citrus withstand overnight frost or short periods of frost. Blossoms and fruit of most citrus are sensitive to frost. Dead leaves that still attached at the tops of trees and outer canopies after periods of cold weather may indicate frost damage. Cover canopies with cloth or plastic sheets overnight to protect them from mild frost. Most types of citrus trees recover well after minor frost damage.

frost damage on citrus

Sunburn: Curling citrus leaves with yellow, brown, or grey spots may be sunburned. This usually occurs on outer leaves that are exposed to the longest periods of direct sunlight during warm-to-hot weather, usually on the south and west sides of trees. A section or two of sunburned leaves usually doesn’t pose a serious problem for mature trees. Provide shade. It may be beneficial to allow sunburned leaves to persist on the tree until weather cools. If a layer of sunburned leaves is removed, the leaves beneath them may also become sunburned.

Sucking Insects: Sucking insects such as aphids, whiteflies, mites, and psyllids, including the Asian Citrus Psyllid, feed on citrus leaves by sucking out plant juices. Check the undersides of leaves for signs of infestation. If infestations are caught early, sucking insects can often be removed or discouraged using a strong stream of water. Eliminate Argentinian ants in areas around infested citrus trees. The ants may fend off beneficial-insect predators in order to harvest the sugary honeydew excreted by sucking insects. Sticky traps, insecticidal soaps, and neem oil may help to reduce populations of insect pests. Trees infested by Asian Citrus Psyllids may become infected by a bacterial disease known as Huanglongbing (“HLB”), for which there is no known cure.

Asian citrus psyllids populate the back of this citrus leaf. Used with the permission of californiacitrusthreat.org

HLB causes uneven leaf yellowing. Used with permission of californiacitrusthreat.org.

Gardeners who believe they may have a citrus tree infested with Asian citrus psyllids or infected with HLB should contact California Citrus Threat Citrus Threat and Disease Prevention Program.

Citrus Leafminers are tiny moth larvae that tunnel through young, new citrus leaves, which may cause citrus leaves to become twisted, distorted, and/or curled. The larvae also roll the edges of citrus leaves around themselves when they pupate. Mine trails are often easily identifiable. Citrus leafminers tend to cause the most harm to young trees with new leaves. Generally the best way to manage citrus leafminers is to do nothing! In most causes only the newest leaves are affected, and damage is not usually sufficient to cause much reduction in fruit yield or long-term harm to trees.

mine trails from citrus leafminer

Don’t know you GardenZeus climate zone?

Other articles of interest:

Year-Round Oranges in Mild Winter Areas of California

Are Your Oranges Ripe? Or Not?

Orange Trees: Should They Have Companion Plants?

This is an updated version of an article originally published on January 14, 2018

Citrus Leaf Curl : Lemon Tree Leaf Problems

Learn about the causes of citrus leaf curl, specially in lemon leaf curling and turning yellow and its treatment and organic control methods that really work. The question is what causes citrus leaf curl, the curling may be upward or downward?
My lime tree which is about 7 years old, is quite green and healthy. Every year it gives me over 100 big size limes. The citrus trees including lemon, lime and orange trees does not demand a lot of attention except regular watering and fertilization 2-3 times a year.

Citrus Leaf Curling due to leaf Miner

Picture Showing
Citrus Leaf Miners Damage

However, there are some problems in citrus tress, specifically citrus leaves curling, yellow leaves and brown spots on the leaves. Curled leaves disease on lemon plants like limes, lemon and orange trees are a matter of concern as it may indicate significant problems.
This year there was prolonged periods of high temperatures and rain so the tree suffered a few diseases. It developed curling of leaves (citrus leaves curling upward or curling downward) and their discoloration.
The picture on the left side shows my lemon tree leaf curling disease due to miner insect. Note the white lines and the white spots on the leaves, showing that the larvae has tunneled through leaf tissue.

Causes of Citrus Leaf Curl

What Causes Citrus Leaf Curl? Citrus leaf curl problem in lemon, lime, oranges and mandarin trees may be caused by the following reasons.

1. Pests Attack on the Citrus Tree causes leaf curling

Aphids, spider mites, citrus leaf miners, mealybugs and scale insects are common sap-sucking pests. These pests feed on citrus leaves and suck the sap from transport tissues. This can cause deformations of leaves causing curling, cupping, wilting and discoloration.

This will not kill the tree, but they will reduce the yield.
The adult citrus leaf miner, a tiny night flying moth (see the picture) do not suck on leaf juices, but their larvae tunnel through leaf tissues as they grow, forming serpentine mines in the tender new leaves of all varieties of citrus leaving a silver trail in their path.
The mining causes the new flush to twist and curl and prevents it from expanding fully.

2. Water Stress

If the leaves are of usual green color and begin to curl inward, it may be the sign of watering problem. Apply a 3 inch layer of organic mulch around your citrus plant (do not touch the mulch to the trunk) and increase watering.

3. Fungal Diseases

Several fungal diseases like bacterial blast and botrytis disease cause the leaves of citrus tree to curl, distort, yellow, wilt and drop prematurely from the tree.

4. Bacterial Blast

If infected with bacterial blast, black lesions start on the petiole and moves to the axil and the infected leaves will curl, wither and drop.

5. Botrytis Disease

If the citrus tree has damage or injuries, then it may be attacked by botrytis disease. The infected areas due to botrytis disease develop grayish, velvet like mold causing leaf discoloration and curling and fruit drop.

6. Potassium Deficiencies in Citrus Trees

If deficient in potassium, the citrus leaves show a yellow cast that are bent downward at the tip. Check the soil pH. Feed with fertilizer high in potassium to treat lemon tree leaves curling down.

Symptoms of Lemon Tree Leaf Problems

The first sign of the pests problem on citrus tress is the presence of squiggly lines on the leaves and then distortion of leaves. If you see undulating white or yellow lines on the green leaf surfaces, then the problem is due to citrus leaf miners. A careful examination of the leaves can reveal tiny pests like aphids, mites, etc. on the underside of leaves.

Treatment of Citrus Leaf Curl

Picture of Adult Citrus Miner
that causes leaf curl

The question is how to control curling of leaves on citrus tree? How to treat Curling Citrus Leaves? If there is a problem of lemon leaf curl, then what should you do to control it and revive your citrus tree.

Organic Treatment of Lemon Tree Leaf Curl

The following home remedies for citrus leaf curl are good for all the citrus trees including lemons, lime, mandarins, oranges, etc.

  1. Cut off any damaged, curled or rolled leaves that might be hiding the pupae. Do not add these to compost bin.
  2. If you see any pests, spray your citrus tree with a solution of neem oil or horticultural oil (pest oil) or with insecticidal soap. Repeat every week until all the signs of insects are gone. I spray my lemon tree with a spray of pest and neem oil combined every third week.
  3. Do not spray the oil if it is too hot. Spray again if it rains after you spray.
  4. Some predatory insects like ladybugs, parasitic wasps and green lacewings help control pests naturally.
  5. Control of bacterial Blast: Protecting the citrus tree from high winds will help reduce the chance of bacterial blast. Apply copper sprays to trees infected with bacterial blast
  6. To avoid fungal disease on Citrus Tree
    1. The citrus tree should be prevented from mechanical injury. Applying copper fungicide before rains can prevent the fungus from reaching the citrus fruit.
    2. Keep your citrus tree healthy, it can better withstand attacks from pests and diseases.
    3. Keep the ground under the tree clean from fallen leaves, blossoms, fruits and twigs. It will reduce the possibility of many citrus problems and even control those problems.

Organic Pest Oil for Citrus Pests | Bronze orange citrus bug

Video on Citrus Leaf Curling Treatment

citrus leaf curl causes,treatment and prevention
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The most common cause of citrus leaf curl are:

  • Pests
  • Disease
  • Water stress
  • Weather
  • Or all of the above

How to treat citrus leaf curl

Pests: Check for evidence on the underside of the leaves. Spray your citrus tree with insecticidal soap or neem oil or a good insecticide from your garden centre. Repeat until the plant begins to recover. Silvery lines or trail on the new leaves means your tree has citrus leafminer. It’s a tiny moth that lays its eggs on the leaf. The hatched larvae tunnel into the leaf and cause the tunnels creating ugly distorted leaves, reducing the harvest on the trees. Spray the plant with Pest Oil or Eco Oil every two weeks ensuring to spray both the top and bottom of the leaves.

Drought: You need to give more water to your fruit trees. Drought stress is the most common cause of leaf curl in citrus, but also the easiest to remedy.

Disease: Several fungal diseases might also be the issues, such as bacterial blast and botrytis disease. Apply copper sprays to trees infected with both, but it could mean a reduction in fruit.

Temperature: Drastic seasonal changes can give your citrus trees stress. They thrive during summer, but if there’s too much heat they can become dehydrated. Also, if it’s too cold in the winter the leaves can become brittle and damaged from the frost. So depending on the climate you can try to balance the temperature accordingly by either providing shade or removing it when you see leaves curling.

The same treatments should work for getting rid of citrus leaf curl, whether you have orange trees, mandarin tree lemon trees, lime trees or peach trees.

Prune and trim

Citrus trees enjoy regular pruning to increase airflow, photosynthesis, and growth. Methods like topping and skirting can help prevent bugs from climbing onto the tree. If left unpruned, your tree will be more prone to the spread of diseases from the soil and other contaminated leaves.

You might also like:

How To Care for Fruit Trees

Cumquats, Lemons, Mandarins and Oranges

This is a problem that can affect all plants in the citrus family. Every summer, flushes of new growth fall victim to attack from the ‘citrus leafminer’.

It starts with the adult, a tiny moth that flutters around at night laying eggs on the fresh new foliage. When they hatch, the little larvae or grubs burrow and ‘mine’ their way into the leaf creating their familiar silvery track marks. When the grubs have had their fill, they move on over to the edge of the leaf and curl it into a cosy shelter where they pupate.

While this activity makes the foliage look ugly and unhealthy, the trees usually survive the attack. It’s OK to prune it off, but not really necessary. The leaves will continue to photosynthesis and produce energy for the tree. However, they would function much better if they weren’t damaged and distorted in this way.

The pest can be controlled organically using an oil-based spray. It’s not used to smother the larvae; instead, it’s applied on the new leaves as soon as they appear, making conditions unfavourable for the adult moth – they won’t lay their eggs on an oily surface. The moth is most active during the summer months so you need to be ready to spray then. Avoid spraying during the heat of the day – that can burn the leaves – wait until the cool of the afternoon. And keep an eye on things – you may need to follow up with a fortnightly spray to maintain a coating of oil on the leaves.

Homemade oil spray
It’s easy to make a low cost oil spray at home. Pour 2 cups of vegetable oil and ½ cup of dishwashing liquid into a jar, mix it well then add 1 tbsp of concentrate to 1 litre of water. Spray to cover the top and bottom of the foliage.

First published: April 2010

Solving Common Citrus Problems

Ants
Keep your tree free of ants! They will farm scales or aphids, etc. moving them from place to place, milking their secretions, and protecting them from beneficial insects. Commercial ant baits that contain boric acid can be helpful. Natural concoctions made at home can also work. You can make an insecticide spray that will also repel ants.
Harmful Insects (Scales, Mealy bugs, Aphids, Mites, etc.)
If you find harmful insects like scales, white-fly, aphids, or mites, all leaves and branches need to be cleaned of all pests AND the honeydew.
Honeydew is sprayed all over the leaves and branches and causes the breakdown of photosynthesis- it is the honeydew that eventually kills the tree, so just drowning the pest in soapy water is not treating the problem they cause.
For a potted tree use a soft cloth and soapy water to scrub off honeydew and remove all pests from the foliage and branches and treat the tree once it is clean with neem oil or horticultural oil. Use a toothbrush in hard to reach areas.
Choosing Insect Pest Treatments
Safer makes an aerosol product with Safer Soap and pyrethrin (a chrysanthemum derivative). Oils and soaps are available in nurseries or garden centers. With any treatment you use, spray the underside of the leaves as well, following the manufacturer’s recommendations. Do not use stronger solutions! Repeat as needed to treat insects newly emerging from eggs. It is not advisable to spray when it is above 90°F or below 40°F, or if it is windy.
Systemic Insecticides
Particularly on plants that produce edible fruit, it is important to use all insecticides cautiously and sparingly. Try to avoid systemic insecticides, since they are moved throughout the plant, and residues may occur in the fruit.
Honeydew
A sticky substance secreted and sprayed by pests as they feed on plant sap. These pests sharp mouth-part penetrates the tissue of the tree and spray honeydew
To monitor for pests, look on the underside of the leaves, on stems and in notches of branches. Distorted leaves maybe the first sign of a pest infestation.
Sticky/Oozing Trunk
Older trees may be afflicted by brown rot gummosis at the base of the trunk, caused by a soil fungus called Phytophthera. Typically, you will notice a sticky substance coming out of the tree’s trunk. Weed eater and rodent damage can lead to gummy bark secretions. Keep the base of the trunk dry, and clear away any soil, mulch, grass, or weeds that might be holding moisture at the base. Trim away infected areas with a sharp (clean) knife, use tree seal to cover the wound and monitor for recurrence. Remove decayed bark to a point where no discoloration is visible. If water hits the trunk from sprinklers, that can trigger the fungus as well. Make sure water does not stand in a basin around the trunk during winter rains or after irrigating. Be sure to always clean pruners with alcohol or another antiseptic cleaner between uses to prevent disease spread among trees.
White Speckled Leaves
If the leaves on your tree are turning white, or if you see white or yellow ‘polka dots,’ your tree may have spider mites. The dots are usually the size of a pin head that can spread to give the leaves a whitish look.
Spider mites suck the juices from leaf cells, causing leaves to bleach out. Spider mites can be controlled with soap and oil sprays, if the problem is discovered early. A very effective product for spider mite and other sucking insect control is Organic Orange TKO. This multi-purpose organic cleaner, used at the most dilute rate, will knock down mites and kill eggs. Be sure to monitor weekly to be ready for any pest recurrence. You may need to spray about every 10 days for three weeks to kill newly hatching eggs.
Removal of the honeydew is essential
Helpful Insects
Spiders, lady beetles, lacewings, are some of the beneficial you may see around citrus trees outdoors. You can sometimes buy beneficial organisms, such as lady beetles at local nurseries.
To deterime what pest is on the tree and more prevention and treatment ideas you can look here- https://lemoncitrustree.com/store/pest-disease

Ask Gardenerd: Curling Leaves on Lemon Tree

Tee wrote in to Ask Gardenerd this week with a common problem. “Why are the leaves on my lemon tree/bush curling inward?”

It could be a number of things, Tee, so let’s start with the most common reason. Pests.

Lemon tree with curled leaf. Check the undersides for pests.

Pests

Sucking insects such as aphids, mealy bugs, white fly, the citrus psyllid, or leaf miners can cause leaf damage or curling. Our first line of defense against sucking insects is to apply a layer of worm castings around the base of the tree, starting 4″ away from the truck out to the drip line (where the branches end). A 1/4″ layer should help the tree fight off sucking insects for awhile. Other treatments include neem oil or soap spray, but we save those as a last resort.

Drought stress caused leaves to curl on this neglected lemon tree.

Watering Issues

Inconsistent watering or drought stress can cause curling leaves. Citrus trees, like most fruit trees, prefer deep but infrequent watering. Overwatering is indicated by yellow leaves, but sometimes underwatering can show up as yellow too. Use this rule of thumb: water deeply 1 time per week for young trees or trees in containers. As they mature, cut back to every 2 weeks, but increase the watering time for a deep soak. From there move to every 3 weeks, 1 month, etc. Soaker hoses left on to trickle overnight will do the trick.

Other Factors

There are other environmental factors that can cause leaf curling. Your soil may be lacking nutrients. Do a simple NPK soil test to find out what’s missing.

Frost and extreme hot weather can also contribute to leaf issues. Keep an eye on the weather forecast and plan to protect your trees from harsh weather with shade cloth or frost blankets.

Take a look at this article from GardenZeus, a site we contributed to a while ago. It goes into more detail about why leaf curl occurs.

Thanks for writing in, Tee. We hope this helps!

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