Have you seen any leaves like this on your tree? If you have—you’re not alone. It’s a classic sign that you might have aphids, and many of our Grow Great Fruit members are reporting high aphid numbers this year.
The curly leaves on these plum trees are the typical response to the sap-sucking aphids taking up residence on the inside of the leaves. It’s different to the Leaf curl disease that you sometimes see on peach and nectarine trees.
If you tease open one of the leaves you’ll usually find aphids of some sort on the inside.
If you get a really bad infestation, there’s no mistaking it because you’ll be able to see hundreds (or thousands) of aphids crawling around, as you can see on this peach tree.
These are black aphids, which are one of the more common types that infest fruit trees, and will usually be seen on cherry, plum, peach and nectarine trees.
Another common type on apple trees is called woolly aphid, for a very good reason:
There’s a third type of aphid that commonly affects fruit trees, and that’s green peach aphid, which — you guessed it — you’ll find on peach and nectarine trees.
Sometimes when you look inside a curly leaf to see if aphids are responsible, you might see something like this instead:
There’s only a couple of live aphids here, but those small black smudges are a really good sign, as they are the dried and shrivelled remains of aphids that have been killed by other insects – “beneficial” insects that do a wonderful job of keeping pest insects under control in healthy, biodiverse gardens.
Inside this leaf is a little community of insects that is a great sign of a healthy ecosystem. A spider, and an aphid-eating wasp are co-habiting and both eating their fill of aphids (or the spider might be eating the wasp – you can never be sure who’s eating who in the insect world!)
We’re often asked how to get rid of aphids, and unfortunately people aren’t usually very happy with the answer!
Biodiversity and patience really are the keys to getting the populations of these pesky pests back under control.
Whatever you do, DON’T SPRAY INSECTICIDE! It can feel like an easy solution, but you’ll inevitably kill predator insects and just make the problem worse. In most commercial orchards, aphid populations are high – and stay high, year after year, due to the use of insecticides that routinely kill the “good” insects that would naturally keep the aphids under control.
It’s expensive, it’s ineffective, and it’s bad for the health of the tree, the user, the eater of the fruit, and the whole ecosystem.
There are a number of home-made remedies that can help in the short term with aphid control, but our experience has shown over many years that similar to bought insecticides, if you rely solely on a solution in a bottle you quickly become dependent on needing to use the same solution every year, and in fact you can be making the problem build up over time.
So, here’s our top 7 tips for getting rid of aphids:
- Monitor your trees regularly, particularly checking inside any leaves that have curled up, so you actually know whether or not you have aphids.
- If you identify that you do have aphids, watch very carefully to see whether you also have any predator insects around that are eating them – spiders, ladybirds and wasps are all particularly voracious aphid-eaters.
- Check whether you have ants in the tree associated with the aphids. Ants like to ‘farm’ aphids by moving them from tree to tree and guarding them from predators.
- If you find ants in your trees, exclude them by any means necessary. Don’t bother trying to kill the ants as they bring excellent eco-services to your garden and are very hard to get rid of, but stop them getting to the aphids by putting sticky tape around the tree between the aphids and the ant nest.
- Focus on building the biodiversity of plant life under your fruit trees. Flowering plants, particularly white and yellow flowers are really good at attracting predator insects and providing them with habitat.
- Unhealthy trees will attract more aphids, so concentrate on improving the health of your tree by improving the soil it’s growing in.
- Use short term solutions (like organic sprays) only in extreme circumstances, and with extreme caution!
We recommend taking a more long term view by creating such a healthy garden that aphid populations are kept under control naturally.
Having said that, short-term solutions can have their place and are part of the “toolbox” of solutions in the Aphid Management Plan you’ll find in our Protect Fruit Trees from Pesky Pests short course.