Olive Grove Oundle | Olive Tree & Mediterranean Plant Specialists

How to Solve Common Plant Diseases

When you’ve spent hours, months and often years curating your garden to be a sanctuary in which you can unwind at the end of a day, entertain throughout the summer and enjoy when the weather is on your side, it can be rather disheartening to see that your plants aren’t looking all too healthy.

Yet, while you will have made the utmost effort to look after your plants – placing them in the conditions they require with a regular feeding and watering routine, disaster can still strike. While some conditions are easy to treat – sometimes a plant may need more water than you have provided or a more sheltered spot – some require more maintenance than this.

Bacteria can either lead to your plant dying off altogether or cause ongoing problems. However, as bacteria is often unable to enter the stem of a plant or foliage, bacteria often forms on leaves or in wounds on the plant.

Below, we’ve collated some of the most common plant diseases and ailments that you may experience and how you can provide some TLC where possible.

Bacterial spot

Bacterial spot can lead to black rot in some cases, so it’s important that you take steps to prevent disease spread where possible.

Caused through warm and wet environments, dark raised spots form to create a spot like appearance. Any infected plants should be destroyed and a copper-based fungicide applied where possible.

Bacterial blight

Unlike bacterial spot, bacterial blight is caused through cool wet weather, leading to yellow spots forming on leaves.

Leaves may not always be too problematic and require no treatment, but it can help to remove infected leaves and ensure that you have spaced your plants far enough apart from one another to avoid bacteria spreading. It can also help to water plants at their root, not from above as this can lead to leaves becoming wet and vulnerable to disease.

Bacterial wilt

Bacteria wilt can cause plants to die suddenly, often with little to no warning. The disease makes its way into the stem of the plant through bacteria in the soil, which leads the stem to become clogged, preventing nutrients and water from reaching the rest of the plant. You’ll notice that leaves become wilted when the disease takes hold. You can check if the disease is bacterial wilt by placing a stem in a glass of water, if it turns milky then you will need to remove the affected plants and soil.

While there is no cure for the disease, planting plants in raised beds or pots allows greater control over the soil quality and drainage. If you are unable to do this, then test that your soil has a pH of around 5.5 and drains well.

Aphids

While small numbers of aphids, small sap-sucking pests, are unlikely to cause harm to plants, if found in large quantities they have the ability to cause distorted growth and leave honeydew on foliage which can cause sooty mould to grow.

To get rid of aphids, you can use a pesticide – however, this is only advisable on small plants where you have the ability to cover it thoroughly. You should also avoid spraying plants which have flowered, as this can cause harm to pollinating bugs. Wiping plants with a soapy water or rubbing alcohol can also make the plant less desirable to aphids.

Ganoderma butt rot

Ganoderma is a fungi which affects a variety of trees and shrubs, including palm trees.

The rot enters the plant through any wounds that have occurred in the root system, and causes a white, sponge-type growth to develop at the base of the tree, leading the wood to rot. Once established, it will change in colour to a striped brown shade and pattern. If you find signs of this disease, you should remove the external infestation and place in a sealed bag to dispose of, before removing the infected tree or shrub too.

Fireblight

Named due to its scorched appearance, fireblight can cause blossoms to wilt, a slimy substance to ooze from infections during wet weather, and shoots to shrivel as the infection spreads.

If you suspect fireblight to have developed, prune out infected areas, cutting back to healthy wood to remove the brown staining which occurs, as well as removing buds which haven’t yet flowered. Any tools you use should be wiped with disinfectant to avoid bacteria spreading.

Once disease takes hold, in some cases it does mean that no cure is available. However, if you spot the signs early, you can ensure that it doesn’t affect the whole of your plant, allowing you to save it where possible. You can find out more about the disease which affect olive trees here.