Like any other plant, olives can be attacked by fungal diseases or pests, especially if they are weakened. However, typical olive pests and diseases are rare in Germany because the tree is too rarely grown in gardens to be widely spread.
What diseases and pests commonly occur on olive trees?
The most common diseases and pests on olive trees include scale insects, spider mites, aphids and fungal diseases such as eyespot. To prevent this, the tree needs optimal care conditions such as lots of sun, a protected location, loose soil, sufficient water without waterlogging and frost-free wintering.
Diseases and pest infestations are usually the result of incorrect care
Harmful insects, fungi and pathogenic bacteria can spread and multiply quickly, especially on weakened plants - such trees often no longer have the strength to defend themselves against the pathogens. Therefore, olive diseases can usually be traced back to incorrect care and/or unfavorable location and weather conditions - there are exceptions. Since prevention is better than cure, ensure the best possible living conditions:
- Sun, sun and more sun
- a protected and not too humid location
- loose, well-drained soil
- no waterlogging
- no frost
- optimal conditions for wintering (temperatures maximum 10 °C)
- regular fertilizer applications
- no pot that is too small or too big
Potted plants are particularly at risk
With these measures you will help ensure that your olive stays as he althy as possible. However, even the best conditions are no guarantee that the tree will not be attacked by pathogens or insects. Potted plants are particularly at risk of disease, especially because olives are not suitable as houseplants.
Scale insects are a common pest
Scale insects in particular are a real pest. These animals appear more often after improper wintering and are difficult to get rid of. You can recognize an infestation by curled and/or dried leaves. If the infestation is larger, a whitish coating can be seen with the naked eye. Scale insects love warmth, which is why they mainly appear in spring after a winter that is too warm. They also multiply extremely quickly - you can only prevent an infestation if you overwinter your olive tree as coolly as possible but frost-free.
Other pests
Other very common pests are spider mites and aphids, which can usually be repelled with a home-made nettle decoction.
Diseases caused by bacteria and fungi
Fungal diseases are also usually due to incorrect overwintering. The so-called eyespot disease occurs very often, and fungal diseases as a result of scale insect infestation are also not uncommon. Fungal diseases can usually only be effectively treated with a (copper-containing) fungicide (€62.00 on Amazon). If your olive tree loses leaves or the leaves turn brown, it is not always just pests at work - such signs often also indicate a lack of water, overwatering or frost damage.
Tips & Tricks
Don't throw away a dry olive tree straight away. Instead, you can prune it vigorously and continue to water it - the tree often sprouts again in spring.