By Julie Christensen
With their arresting tart flavor, limes are most often used for their juice, which flavors dishes from key lime pie to margaritas to guacamole. Like all citrus trees, limes are heat-loving plants that only grow outdoors in USDA plant hardiness zones 9 through 11. When it comes to varieties, you have several options. Persian limes (Citrus latifolia) are the type most often found commercially. They’re large and sweet, with a mild lime flavor. Key limes (Citrus aurantiifolia) are smaller, with intense lime flavor and a thin skin. Kaffir limes (Citrus hystrix) have a tart, acidic flavor and a bumpy rind.
Lime trees have the same cultural requirements as all citrus trees, and most disease problems can be prevented or minimized by good care. Plant them in full sun in light, well-draining soil. The trees don’t tolerate heavy clay soils or those high in salt. Plant them in early spring so they have time to become established before the heat of summer arrives. Plant them so the top of the rootball sits 1 inch above the soil. This planting strategy can help prevent some fungal diseases, such as gummosis.
Lime trees, and in particular, young lime trees, can suffer from sunburn or sunscald, which causes peeling, damaged bark. Paint the trees with a mixture of one part white flat latex paint and one part water or use a commercial tree wrap.
Water lime trees once or twice a week during the growing season so the soil stays moist to a depth of 6 inches beneath the surface. It’s better to water deeply less frequently. Signs of overwatering include cupped, drooping leaves. If this occurs, let the soil dry out before watering again.
In spite of the above precautions, lime trees occasionally suffer disease and insect pests. Below are the most common problems you’re likely to see and strategies for treatment.
Black Sooty Mold
Black sooty mold is a fungal growth that is caused by aphid infestations. The aphids excrete a sticky substance called honeydew as they feed on the leaves and stems of the lime tree. The aphids alone usually cause only minor damage. The black sooty mold feeds on the honeydew. It forms a black, powdery substance over the leaves and stems, which is not only unattractive, but can be destructive. In severe cases, it can stunt growth and kill the leaves. The mold sometimes grows on the fruit, as well. To control black sooty mold, you must control the aphids. Spray the tree with a heavy stream of water to dislodge the aphids and remove the mold. Or spray the tree with insecticidal soap or oil. Use a product labeled for citrus trees, and apply it on overcast days.
Fruit Diseases
Brown fruit rot causes tan or brown spots to develop on fruit. The disease can spread after harvest when diseased limes are stored with healthy ones. Spray the trees with a copper-based fungicide before the rainy season. Store affected fruits separately and use them immediately.
Stylar end rot causes brown spots to develop on the blossom end of the fruit. Decay enters these spots, destroying the entire fruit. To avoid stylar end rot, pick limes in the afternoon in dry weather. Handle them gently.
Foliage Diseases
Citrus canker is a bacterial infection that causes brown or yellow spots on leaves, which can also spread to the fruit. To prevent the disease, spray trees with a copper-based fungicide in the spring. Space lime trees so they get adequate air circulation. Use soaker hoses, instead of overhead sprinklers because wet leaves can spread the disease.
Citrus greening is a serious disease spread by the Asian citrus psyllid. It causes yellowed leaf veins. The leaves and stems may die back and the fruit turns bitter. There is no cure for this disease. Remove and destroy infected trees.
Trunk and Root Diseases
The most common problems you’ll encounter are those caused by the Phytophthora fungus. This pathogen causes root rots and trunk cankers. You might notice stunted growth, cracking bark or liquid oozing from the trunk. If cankers girdle the tree, it will die. To prevent root rots and cankers, plant trees in well-draining soil and avoid planting them too deeply. Avoid overwatering because soggy soils can contribute to the disease. Prune out infected branches and disinfect your tools between cuts with a solution of one part chlorine bleach to ten parts water.
For more information, visit the following link:
Citrus for the Home Garden from the University of California Extension
Citrus Diseases and Disorders from the University of California.
Julie Christensen learned about gardening on her grandfather’s farm and mother’s vegetable garden in southern Idaho. Today, she lives and gardens on the high plains of Colorado. When she’s not digging in the dirt, Julie writes about food, education, parenting and gardening.
I have a young grapefruit tree that has some leaves with about 1″ wide in areas of coppery brown spots on back near edges. It does not rub off. No insects involved. Does not show through to top surface as brown, but on some leaves there is an “ochre” color on top surface where the brown is underneith
I have looked at just abpit all info on net and cannot find problem
Hi Marie ,
The wonderful understandable post you share on the page about the removing of common root fungus disease comming in the lime trees rapidly ,If you want to remove this kind of disease from the lime trees located in the public garden ,Then the best way for it to remove the root fungus from the trees of a lime by providing a filtered water daily in the time of morning t to all the trees of a lime in a lawn and also spray a medicine of root fungus which help you in the removing of root fungus diseases o comming in the lime trees in a very short interval of time after following these guidelines are mentioned in this passage of information .
Thanks
VERY CONFUSING RESPONSE!!!! VERY POOR GRAMMAR!!!!!
Question – Persian lime tree in the ground less than one year. The leaves on the outer parts of the branches have a shiny coating on them consistent with what you would see with worm activity, but I can find no bugs after many checks. Result is wilted leaves that are lighter in color than others. Issue affects all leaves from end of branch to a point then stop abruptly. I sprayed it with Sevin, thinking it was a bug. No change. Any help would be appreciated.
I know the above post was 2017, but in the past month, I’ve notice the same activity on my key lime tree. New growth looks good for a few days or so, then it curls in and or wilts. Some of the older leaves have turned spotty shades of light green. Right now the tree has many new key limes growing. I did have small moths that I’ve noticed on the tree. I’ve sprayed 2 times with Sevin. I don’t want to lose my Key lime tree. Any help would be appreciated. Thanks! [email protected]
Need pictures of limes that suffer overwatering.
Hi there,
I have just bought a young potted Tahitian lime tree. For the most part; the leaves and trunk look quite green and healthy. Some roots appear to be trying to escape out of the bottom which I assume means it needs a bigger pot. I am concerned however about the brown spots on some of the leaves. It seems strange that they appear on such a new plant. I have recently read about disease citrus canter and the positive affect a copper-based fungicide can have. Is there a way to determine it is in fact this disease or am I over worrying/overthinking.
I have an indoor dwarf lemon trees. Lately I been noticing leaves falling. Then I noticed there’s insects all over the plants. They are small and flat, no smell . Don’t know what they are but I believe it’s the reason why my plants are dying. Pls help.
I have a small mexican key lime tree that has like tiny scratch like marks on the fruit
I have the same problem. I think they’re actually some kind of insect. Very odd looking. Did anybody ever answer your question?
I have a dwarf lime tree. It has sticky leaves these like brown bug eggs all over. On the top side of the leave, the bottom, and the bark.
I have 2 Meyer lemon trees and one large Italian lemon tree as well as an infertile orange tree, 10 years old, w/ no flowers or fruit. ever.
My question is, I have found very small black beetle type insects mostly on under the leaves. I have used a natural powder that I have sprayed every week all summer long, but the insects are thriving . I am so afraid of losing my trees.There are too many to count.I am using Diatamaceous Earth on all the citrus trees. They have spread to one another . I am so upset.I dont know what to use or how to use anything.The DE has done nothing to get rid of these insects.They have infested all the trees.
I have a Mexican lime tree moved from pot on deck to ground three /four years ago. It had very nice fruit when in pot but nothing since until i started spraying it with Jack’s organic spray because it wasn’t setting any flowers. it now has these humungous limes that are mostly pith three to four times nornal size. the leaves still curl up and look strange but the tree is vibrant green and growing. It is in an area that gets watered twice a week for ten min. Its about six foot tall and dense.
my lime tree was planted a year ago. one week ago it looked healthy, had a few blossoms and tiny limes. I noticed the leaves started curling. now the tree looks dead, the leaves are all brown. all this in a weeks time.
Hi,
I have a Tahitian Lime tree which lived in a pot for a year or so and then has been planted out for two years next to an orange and a small lemon tree and watered regularly. It gets full sun in the middle of the day. This year it has produced a huge crop but quite a few of the fruit have developed a soft brownish circle of varying sizes at their bottoms – covering up to 20% of each fruits surface, When cut, there doesn’t seem to be any internal ‘rot’, for want of a better word but I’d really like to know what it is and what’s causing it. Can you offer me any advice?
Hopefully, Peter
If I send a picture of my poor Kefir Lime tree can you diagnose the problem? The new leaves are mottled with yellow. Thank you.
Hi, can I send you some photos of my limes to get a diagnosis ?
Hi, we recently had a lot of rain. I have a baress lime tree that is about 5 years old. Last year I had a lot of limes. This year very few and now older leaves are yellow and have brown spots on them. New growth is a pretty green. Don’t know if I should do something to it. Any help you can give me will be appreciated. They don’t have a ring around the spots. Just brown spots. Thank you. Mar
Hi, can I send you some photos of my Kaffir lime tree to get cure for it ?
I have a mature lime tree that has always produced great lines. Currently the lines are I nice size but they are developing a brown area and falling off the tree daily. I sprayed with Bonide citrus orchard spray about 3 weeks ago. At that time this was not happening. I’m hoping you can help me.