Why are the leaves on my lemon tree sticky?
Posted on: July 23rd, 2015
More and more British homeowners are bringing the Mediterranean to their gardens by investing in a fruit tree or two. These colourful additions can brighten up a courtyard, orchard or lawn and keep you self-sufficient in whichever variety of fruit takes your fancy.
Although they’re not particularly difficult to maintain, fruit trees can leave their owners literally stumped when they encounter a problem.
One of the most frequently asked questions about lemon trees in particular is why they have sticky leaves. We will attempt to address that right here but if you’re unsure of what to do, it’s always worth getting a professional to come out and take a proper look.
Sticky leaves of any tree are usually evidence of an aphid infestation or occasionally an infestation of a tree above the lemon tree.
Aphids feed on the sap of phloem vessels – this is the living tissue that carries organic nutrients to the plant for healthy growth.
These insects pierce the leaf using their mouth and suction up the sap into their food canal.
Aphids suction up more sap than they can physically digest which means the excess drops onto leaves below. As the sap dries, it leaves a sticky, sugary substance known as honeydew.
Occasionally the sap residue will also be flecked with black. This indicates the presence of a fungus called sooty mould. While this might appear alarming, the fungus relies on the sap itself to feed and not the leaves, therefore causing no further damage.
Colonies of ants often eat the honeydew which is rich in energy. This provides the lemon tree with additional protection from predators and creates an ecological balance.
Where infestations are unmanageable, it is advisable to prune your lemon tree to remove some of the insect colonies.
Another useful tip is to spray the lemon tree with water from a hose which will help to wash and disperse some of the population and prevent them from finding their way back.
It is possible to buy natural oils such as Neem oil which infects and kills aphids and won’t harm your tree. You could also try and introduce other predators organically to control your aphid populations. Ladybirds and wasps are particularly partial to aphids.
The good news is lemon trees are one of the toughest citrus trees and will withstand many problems, including aphid infestations.
We hope you found this article on ‘Why are the leaves on my lemon tree sticky’ useful, if you would like to discuss any aspect of this article then please do not hesitate to call Prince Tree Surgery on 01277 229709.