Dealing with Sticky Leaves on Lemon Trees

Sticky leaves on lemon trees are a common issue that can drive lemon tree owners crazy. The sticky substance coating the leaves is called honeydew and it is secreted by sap-sucking insects that feed on the lemon tree. Left unchecked, these pests can stunt your tree’s growth and ruin the developing lemons. But with some diligent monitoring and treatment, you can get the sticky leaf situation under control.

What Causes Sticky Leaves on Lemon Trees?

The main culprits behind sticky lemon tree leaves are

• Aphids – Small soft-bodied insects that cluster on young shoots and the undersides of leaves. They come in many colors like green yellow, black, red, or brown. As they feed, aphids secrete honeydew.

• Whiteflies – Tiny white insects that congregate on leaf undersides. They are weak fliers and will flutter up briefly when disturbed before settling back down. Their honeydew secretions promote sooty mold growth.

• Scale – Immobile insects encased in a waxy shell that attach to stems and leaves. Common scale species are brown soft scale, red scale, and black scale. Honeydew drips from them onto leaves.

• Mealybugs – Soft, oval insects covered in white powder that look like small bits of cotton. They cluster together to feed, excreting honeydew.

Carefully inspect new growth and the undersides of leaves for any clusters of these sap-feeding insects. Their infestations make leaves unpleasantly sticky.

Dangers of Sticky Leaves

While the honeydew alone can make leaves sticky and unpleasant, it also leads to additional issues:

• Growth of black sooty mold on leaves which blocks light needed for photosynthesis.

• Attraction of nuisance ants that will “farm” the honeydew.

• Spread of viral diseases as sap-sucking insects migrate from plant to plant.

• Cosmetic damage to lemons which get coated in sticky honeydew and sooty mold.

• Weakening and stunting of trees from the constant sap feeding.

To keep your lemon tree healthy and producing abundant fruit, it’s vital to resolve the sticky leaf problem.

Getting Rid of Sticky Leaves on Lemon Trees

To fix sticky leaves on your lemon tree:

• Wash leaves – Use a soft cloth, sponge or gentle spray to remove honeydew and sooty mold.

• Apply horticultural oils – These oils smother insects by blocking their breathing pores. Spray every 7-14 days for 2-3 applications.

• Use insecticidal soap – Target sap feeding juvenile insects by spraying every 5-7 days for a few weeks.

• Release beneficial insects – Ladybugs, lacewings and other predators feed on sap-suckers. Restock every 2-3 weeks during heavy infestations.

• Apply neem oil – It disrupts growth and reproduction. Spray thoroughly every 7-14 days for a few weeks.

• Use systemic insecticides – Soil drenches or tree injections provide lasting protection against sap feeders.

An integrated pest management approach using several methods together will eliminate sticky leaves. Don’t let these annoying insects win!

Preventing Future Sticky Leaf Problems

Stopping sticky leaves before they start is ideal. Follow these proactive tips:

• Inspect new trees carefully for signs of pests before buying. Quarantine if needed.

• Remove dead leaves, dropped fruit and debris where insects shelter.

• Promote optimal tree health with proper fertilizing, watering and pest monitoring.

• Apply horticultural oils during the dormant season to suffocate overwintering pests.

• Release beneficial insects early to get established before sap feeders proliferate.

• Use sticky traps for early detection of whiteflies and other pests.

• Prune trees for good airflow and spray penetration.

• Monitor weekly for any signs of honeydew or insects.

With vigilant integrated pest management, you can avoid sticky leaf issues altogether. Don’t let these frustrating pests detract from growing gorgeous, productive lemon trees.

Frequently Asked Questions

How do I get rid of the sticky residue on my lemon tree leaves?

Wash off the insects and sticky honeydew by spraying the leaves with a strong jet of water or rubbing them with a soft cloth or sponge dipped in warm soapy water. Rinse afterwards with clean water. For stubborn sticky buildup, use a horticultural oil labeled for use on citrus to help dissolve the waxy residue.

Why are my lemon tree leaves sticky?

Sticky leaves are caused by sap-sucking insects like aphids, whiteflies, scale, and mealybugs feeding on your tree. As they feed on the sap, they excrete excess sugars as honeydew which coats the leaves in a tacky mess. Identify and treat the insects to eliminate the sticky honeydew.

What causes white dots on lemon tree leaves?

White dots on the leaves are typically a sign of scale insect infestations. The dots are the waxy coverings of the immobile adult female scales that attach themselves to the leaves and stems. Use a magnifying glass to examine them. Remove scales manually and treat with horticultural oil or insecticidal soap.

How do I treat scale insects on my lemon tree?

Start by spraying the tree thoroughly with insecticidal soap, neem oil or horticultural oil. Use a soft brush or cloth to gently rub off any loose scales. For severe infestations, apply a systemic insecticide drench to the soil. Prune away heavily infested branches. Release ladybugs or lacewings to naturally control scale pests.

Should I mist my indoor lemon tree?

No, misting is not recommended for lemon trees. Citrus prefer a drier environment and misting raises the humidity, encouraging fungal growth. Occasional light misting of indoor trees is fine but avoid keeping the leaves perpetually damp. Allow soil to dry between waterings and provide good airflow around the lemon tree.

Sticky leaves on lemon trees happen but with monitoring and integrated treatment, you can protect your tree’s health and your sanity! Don’t let sap-sucking pests get the upper hand in your orchard.