Spotted a black, sooty substance on your White Stinkwood? Or tufts of cotton wool stuck in your Celtis Africana? You could be facing an infestation of winter pests that will wreak havoc on your garden if you don’t take action.
Here are three common pests that you may come across in your garden this winter:
The woolly aphid is a sap-sucking insect that was accidentally introduced to South Africa from the northern hemisphere. They are small, white and fluffy, hence the name – woolly aphid. As they feed, these aphids produce a white, waxy substance which resembles cotton wool. Woolly aphids reproduce rapidly and because they’re winged, they can easily colonise new locations.
An infestation of woolly aphids is not simply an inconvenience. They can have a devastating impact on your trees, causing leaves to drop, stunting the growth of the tree and in severe cases may result in the death of the tree.
Treatment: Your local garden centre should stock a variety of pesticides (including organic pesticides) formulated to treat a range of pests, including woolly aphids. Follow the instructions on the bottle and take the necessary precautions.
Like their woolly cousins, aphids are sap-suckers that reproduce quickly and can cause severe damage to tree, shrubs and plants. Aphids excrete honeydew which, although it sounds pleasant, can lead to the appearance of sooty mould.
Aphids may also carry viruses or bacteria and can infect plants and are considered one of the most destructive pests in the garden. They tend to congregate in bunches which makes them easy to identify.
Treatment: There are a number of simple, organic aphid remedies. You can make a soapy solution with a mild detergent and water with which you spray the affected areas two or three times a week.
You could also introduce ladybugs into your garden to take control the aphid population. Some nurseries even stock the larvae in packs with full instructions on when and where to release them for maximum effectiveness.
Many commercial pesticides are also available for treating aphids and should resolve your infestation with regular, careful use.
Italian Cypress Aphid
These aphids not only excrete honeydew, they also inject a toxin into the plants they feed on. They are partial to conifers and the toxin they release damages the foliage, causing it to yellow and eventually turn brown.
Italian Cypress Aphids reach their peak infestation during the colder months of the year, starting in March and lasting until August. Unlike ordinary aphids which cluster around new growth, these aphids create massive, hidden colonies on main stems. Unless you inspect your trees regularly, you may not spot them in time
Treatment: While ants will defend these colonies of Italian Cypress Aphids in exchange for honeydew they do have some natural enemies such as ladybugs and praying mantis. Managing any ant nests around your trees will help to control the Cypress Aphid population, and any insecticide you use should not pose a danger to natural predators.
A word about Sooty Mould
Sooty Mould is a fungus which often appears alongside aphid infestations. All aphids secrete honeydew, a sweet sticky liquid that remains after they have ingested the sap from a plant or tree. Spores of sooty mould grow in this honeydew and may spread to surrounding trees and plants.
Although this mould is not parasitic and will not cause direct damage, it is unsightly and may affect photosynthesis. The only way to manage Sooty Mould is by treating the underlying cause which is usually aphid infestation.
If you’re not sure whether your trees are infected, give Brands a call and let their certified horticulturist give you his professional opinion. A quick consultation, along with professional advice is all you need to keep your trees pest-free this winter.