Like any other plant, orange trees can be attacked by pests or fungi. With a little attention, small and large disasters can usually be avoided. A close weekly look under the leaves and on the branches often reveals in advance a newly settled colony of aphids or even a new scale insect population that is slowly migrating up the branches.
What diseases can affect an orange tree?
Orange tree diseases can be caused by fungal infestation, root rot or pests such as scale insects, aphids, mealybugs and mealybugs as well as red citrus spider mites. Early detection and treatment with mineral oil spray, potassium soap or increased humidity prevents further damage.
Fungal diseases
Fungi can basically colonize all parts of the plant, from the roots to the flowers and fruits, the entire orange tree is often infected. Mushrooms feel particularly comfortable in a warm, humid climate, which is why you should react in good time to any signs of suspicion, especially with the heat and moisture-loving oranges. Fungal infestation occurs particularly often after overwintering that is too warm, e.g. B. in a warm living room, or after a scale insect infestation.
Base rot leads to tree death
The so-called root rot is probably also caused by a fungus and usually begins at the lower end of the trunk. Initially, some parts of the bark turn dark and later flake off. The tree secretes a rubbery liquid in the affected areas. The disease is highly contagious and also spreads throughout the entire tree - including the roots, which is why the orange tree eventually dies.
The most common pests
In addition to fungi, numerous insect pests also cause problems.
Scale insects
These lice can be recognized by their small scutes and are usually located on the undersides of the leaves along the pathways and on the shoots. The larval form is very small (about 0.5 mm), white and very mobile. Often the first thing you discover is the sticky honey excretions, which the animals spray up to a distance of 15 centimeters. A sooty mold fungus likes to settle on these excretions, which turns the leaf black. The adult scale insects can be treated most gently with a mineral oil spray, the larvae with potassium soap.
Leaf, mealybugs and mealybugs
An aphid infestation can be recognized from afar by the stunted shoots and twisted leaves. They prefer to stay on soft new shoots. Mealybugs and mealybugs are whitish to pink and up to four millimeters long. When infested, they can multiply explosively. They are located on the undersides of leaves, in leaf axils and shoot tips. These lice are treated with the same means as other sucking insects, but several times in a row. This ensures that the young animals that later hatch from the eggs are also controlled.
Red citrus spider mite
This spider mite is one of the sap-sucking arachnids. The adults are just under 0.5 millimeters long and red. An infestation can be recognized by light spots on the leaves. The animals usually sit on the undersides of the leaves. If the infestation is severe, they also form webs there and in the leaf axils, which can spread to the entire shoot tip. Spider mites prefer dry air. Increasing the humidity therefore reduces the infestation. Predatory mites can also limit an infestation, but they need temperatures of around 20 °C. If spider mites occur more often, they can be controlled with a mineral oil spray or potassium soap.
Tips & Tricks
A lot of ant activity in the trunk and root area is extremely suspicious. On the one hand, ants love the sugar excretions of the lice and therefore look after these pests with devotion; on the other hand, they damage the roots of the plants through their digging activities with their own nursery created in the root ball.
