Why Are Lemon Tree Leaves Sticky? Solving the Mystery!

In optimal conditions, lemon tree leaves are not sticky! 

Some circumstances may make lemon tree leaves sticky like Insect pests feeding on leaf sap and secreting honeydew. This makes the leaves sticky and creates a few problems for the trees.  

Normal Texture and Appearance of Lemon Trees 

First-time lemon tree growers may not know what the norm is when it comes to lemon tree appearance. It could prove difficult to grow something you have never seen. So, we urge you to go have a look at a lemon orchard if you can. 

But, if not, we’ll tell you what’s normal and what’s not! 

What Should Lemon Tree Leaves Look Like?

Lemon tree leaves are small to medium in size (depending on the age of the tree). Typical leaves are oval in shape but elongated. Also, leaves should feel dry or wet (after watering) and definitely not sticky! 

The leaves are also supposed to feel smooth on the top and matte-like on the underside. When young, leaves are light green and then darken as the tree matures.

Small droplets of water may grace the green leaves as the top has a waxy layer that’s water-proof. 

What Shouldn’t Lemon Tree Leaves Look Like? 

Any sign of off-colored leaves is not normal at all. Leaves should never be any color other than a shade of green. Hence, yellow, brown, or even black leaves are a sign of inappropriate conditions, or, ill-health! 

Additionally, lemon leaves should not feel bumpy and have ‘knots’ on the surface. If they do have this, it could be a disease or symptom of a pest infestation.

Inspect your leaves carefully to try and spot the culprits. You may need to use a magnifying glass to find some of them as they are extremely small. Thus, it makes them invisible to the eye.

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What is the Sticky Residue on My Lemon Tree Leaves?

This is the question you will be asking if you have sticky lemon leaves! 

Leaves are supposed to feel normally dry but moderately moist when crushed. What lemon leaves really shouldn’t feel like is wet candy, sticky to the touch. If it is, something has gone terribly wrong! 

In almost all cases, sticky lemon leaves indicate a sugary substance is present. This sticky material is called honeydew. 

You might be wondering where the honeydew comes from. 

Honeydew is a substance many insect pests release after feeding on the leaf sap of a plant. In this case, your lemon leaves are the source of food for the insects. The more these insects feed, the more honeydew will be excreted.  

The honeydew is basically your lemon tree’s sap but with a higher sugar concentration. This is alarming because if the population of insects is high enough, your tree could end up severely drained of its sap. 

The tree needs this sap as a source of food! Without it, growth may be hindered and the tree could start to appear stunted and fruitless.

NOTE: Apart from the production of honeydew by sap-drinking insects, sap may continue to leak out of the puncture wounds. This could also contribute to the stickiness of lemon tree leaves.   

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Lemon Tree Pests That Produce Honeydew

When looking at all the insects that can make your lemon trees sticky, there are quite a few insects. These insects are the usual suspects that can be found feeding on the sap of many plants. 

Here are the insects notorious for feeding on lemon leaf sap and producing honeydew:

  • Aphids 
  • Scale
  • Mealybugs
  • Whitefly 

Controlling Sap-Feeding Insects on Lemon Trees

A great deal of keeping lemon trees happy and healthy revolves around making sure that sap-eating pests are kept away.

Keeping them away also means that you can keep ants away. This is good news as it stops leaf damage and leaves fruit uncompromised.  

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How to Get Rid of Aphids on Lemon Trees? 

Getting rid of aphids on lemon trees is a common problem many gardeners face. But there are efficient techniques to do so. Here are a few of them.

Wiping with Soap Solution

In a bucket of water (3.5L) add a few drops of liquid soap, detergent, or alcohol. Alternatively, you can use cayenne pepper powder or insecticidal soap. Dip cotton wool into this solution and wipe each leaf down with it. 

You will have to do this again after 2 or 3 days for the next 3 weeks. 

Spraying with Pressurized Water

Have a garden hose? Put it on full and blast the aphids away! However, make sure your lemon trees are established and can take the pressure (no pun intended)!

But, if you want to get rid of all your aphids, we advise using it in combination with the wiping technique. 

Using Neem Oil

Once populations are decreased or eliminated, you will want to prevent them from coming back. Apply Neem oil on the stems as this will make the wood slippery and hard to grip. Hopefully, this is enough to dissuade them.

Invite Natural Predators

Aphids have a few pests that naturally love to feed on them. Ladybird beetles, parasitoid wasps, and rove beetles all enjoy feasting off of aphids.

So, go ahead and invite them! Their presence will definitely help to control aphid populations and perhaps ward them off for good.  

How to Get Rid of Ants on Lemon Trees?

If you have honeydew on lemon leaves you probably have ants as well! 

To get ants off your lemon tree, set up a food trap away from your lemon tree, offering something better than honeydew. Also, you can wrap the tree trunk with sticky tape (cello tape) on which the ants will be stuck. 

Eventually, the ants will take the hint and stop coming. But, remember, you have to first get rid of aphids on lemon trees to stop ants.

If Honeydew Is Harmless, Why Get Rid of It?

Honeydew itself as a substance may not be harming your lemon trees in any way. So, you might ask why you should remove honeydew from lemon trees.

This is true, honeydew does not pose any threat. It’s usually what the honeydew attracts that is damaging. Let us look at what it attracts below.

Ants, A Gardener’s Menace! 

Sure ants are a vital part of a typical garden ecosystem. They help degrade the material, aerate the soil, and can even play a role in spreading seeds. However, when it comes to honeydew they are not a friend but rather a foe! 

Honeydew and insects that excrete honeydew will attract another pest that loves to eat the sugary substance. Know what they are? If you guessed ants, you are correct. Ants are hardworking insects. 

However, their daily activities create a requirement for a high-energy meal. Honeydew happens to be on the menu!

Ants love this substance and will go to extreme lengths to protect their food source. Their food source is honeydew producers, aphids included. 

Now, for lemon tree growers, aphids spell bad news (for any plant actually). High populations of aphids will start to diminish the leaves of the trees they feed on. Getting rid of them is a must! 

Dust 

Honeydew is naturally a sticky substance due to the high sugar concentration which only amplifies as water evaporates. But as the honeydew concentrates in quality and quantity, its ability to catch particles increases.

Dust could heavily attach to the honeydew on lemon tree leaves. If too much dust attaches to the lemon tree leaves, they could form a thick layer. This could possibly block pores in the leaves, this disturbs transpiration.

Also, thick layers of honeydew and dust could possibly inhibit photosynthesis.

Chlorophyll and sunlight may not be able to make contact as the dust layer will make the leaves darker. As a result, the lemon tree leaves will fail to make food. 

Sooty Mildew  

The worst effect of honeydew could very well be this, sooty mildew! This is a fungal infection that grows over honeydew.

The name sooty mildew is an indication of the appearance of the mycelium which resembles a layer of soot. 

Once infected by this fungal infection, lemon trees will struggle to grow normally unless you take action. Getting rid of sooty mildew involves dealing with the source- honeydew-producing insects. 

You will also have to get rid of their protection, ants!  

As soon as the honeydew producer population decreases, the mildew will wear away naturally. 

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How Do You Get Rid of Sticky Residue on Plants? – Natural Pesticide for Lemon Tree

Honeydew is water-soluble. This means you can get rid of sticky residue on lemon tree leaves by rinsing thoroughly with water. Or, you could use a wet cloth or cotton clumps to gently wipe it off. 

Getting rid of the sticky honeydew should only be done once you have successfully removed all, or, the majority of the honeydew-producing insects.

Wiping off the honeydew before all the producers are gone will just result in it accumulating all over again! You must try to avoid this as it will be time-consuming and a waste of effort. 

Conclusion

Lemon tree leaves are sticky because of the presence of honeydew or sap bleeding from puncture wounds. Aphids, scale insects, and mealybugs feed on lemon tree leaf sap and excrete honeydew.

Also, honeydew can attract ants who eat the substance. Ultimately, the ants will protect the honeydew-producing insects by warding off natural insect predators. 

Want to be ant and honeydew-free? Unfortunately, you must first get rid of honeydew-producing insects (aphids, scale insects, mealybug). This can be done with several wipe-downs using soapy water and cotton wool. 

After this, wash or wipe the sticky lemon tree leaves with water to remove honeydew. 

FAQs

My lemon tree has sticky leaves, is this normal?

It certainly is not normal! The leaves should be dry and have a wax-like layer that is glossy on the top part of the leaves.
The underside should have a matte texture. Also, the leaves should be green (light/dark). Sticky substances can make leaves gray, black, or brown in color.

Can sticky residue from lemon tree leaves?

Yes, you can remove sticky residue from lemon tree leaves using water and any other tool you may need.