Why Are My Fig Tree Leaves Sticky and Covered in Aphids?

Finding clusters of small soft-bodied insects on your fig tree's young leaves and shoot tips, accompanied by sticky deposits on the leaves and possibly black sooty mould growing on that stickiness, means aphids are feeding on the tree. While a healthy established fig tree can tolerate a modest aphid population without serious harm, a heavy infestation weakens the tree, distorts the growth of young shoots and can spread viral diseases. Dealing with aphids promptly and in the right way gives the best results.

Which aphids attack figs?

Several aphid species feed on fig trees. The most common in the UK is Homotoma ficus, the fig psyllid, which is technically a jumping plant louse rather than a true aphid but causes similar honeydew and sooty mould symptoms. True aphids of various species also feed on fig tree sap, particularly on the soft growth of young shoots in spring and early summer. They range from pale green to black in colour and are found in dense clusters on the undersides of young leaves and at shoot tips.

Biological control — natural predators

The most effective long-term approach to aphid management is to encourage and protect the natural predators that feed on them. Ladybirds, lacewings, hoverfly larvae and parasitic wasps all feed on aphids and can dramatically reduce populations if given the chance. Avoid using broad-spectrum insecticides, which kill these beneficials. Plant nectar-rich flowers near the fig tree to attract and support hoverfly and parasitic wasp populations.

Physical removal

For localised aphid colonies on accessible shoots, physical removal is both effective and harmless to beneficials. Rub colonies off with your fingers, squash them between finger and thumb, or wipe the affected leaves and shoot tips with a damp cloth. On young container trees, a strong jet of water from a hose can dislodge large numbers of aphids — they are unable to return to the plant once knocked off. Repeat every few days until the colony is broken up.

Soft soap spray

A soft insecticidal soap spray — either a proprietary product or a homemade solution of washing-up liquid diluted to a very weak concentration — kills aphids on contact by blocking their breathing pores. Spray directly onto the colonies, covering the undersides of leaves where aphids congregate. Repeat after rain or every five to seven days. Soft soap breaks down rapidly and has minimal impact on most beneficial insects if applied carefully.

Addressing sooty mould

Once the aphid population is controlled, the honeydew production stops and the existing sooty mould gradually weathers off. Wiping affected leaves with a damp cloth removes it more quickly. Sooty mould itself does not infect the plant but it reduces photosynthesis by blocking light, so its removal from heavily coated leaves is worthwhile.