Walnut trees are very common deciduous trees throughout Europe, although they are also found in Asia. They have several uses, both for the native fauna and for humans, since they provide a lot of shade, food since their fruits are edible, and high-quality furniture is made with the wood due to its great resistance to insect attack.
And I want to talk to you about them precisely below: those pathogenic insects and microorganisms that, at some point, can cause problems. But what exactly are walnut tree diseases and how are they treated?
What are the diseases of walnut trees?
Being a very resistant plant, it can actually have very few diseases. These manifest when the health of the tree is weakened for some reason, either due to excess water in its roots, extreme heat or because it has been pruned with a tool without disinfection, for example. They are the following:
Anthracnose
Image - Wikimedia / Jerzy Opioła
La anthracnose or canker is a fungal disease that is caused by various pathogenic fungi. In the case of walnut, the main cause is the Gnomonia leptostyla. This it causes the leaves, branches and fruits to have rounded brown spots. You have to be a little vigilant, since these spots start out very small, but over time, they get bigger.
Like the vast majority of fungi, Gnomonia It is favored by a warm environment with air humidity above 90%. For this reason, it is advisable to apply a fungicide against anthracnose (such as this, which is one sachet for 750ml of water) in spring as preventive, and also as soon as symptoms appear.
bacteriosis
Image – Flickr/Hermes Almond
Black walnut plague or bacteriosis, as its name suggests, is caused by pathogenic bacteria. In the specific case of walnut we have to talk about the Xanthomonas arboricola, a type of bacteria that causes small, oily black spots on leaves, with a yellowish center. Sometimes, it also affects flowers and fruits.
It is a disease that it can appear especially after the rains, and when temperatures are still mild. Unfortunately, there is no treatment: as soon as the tree shows the first symptoms, the affected parts must be removed.
What pests can it have?
El Juglans regal It is a fruit tree that is a pleasure to grow, since it is rare for it to get sick or for insects to attack it. But we can never forget that it is a living being, and that as such it can get sick if the conditions weaken it. For this reason, it is also important to know the pests that can affect you:
wood borer
Image – Flickr/Camponotus Vagus
The wood borer, also called a borer, is an insect that can cause a lot of trouble for hickory trees. Both the yellow drill (Zeuzera Pyrina) like red (cossus cossus) whose larvae excavate galleries in the branches. This causes the leaves to wilt quickly as they run out of food supply.
Symptoms appear towards the end of spring and almost always in the upper part of the tree canopy.. It is important that the walnut tree be treated as soon as possible with an insecticide that eliminates borers, such as this which is an envelope for 12 liters of water, so that it does not continue to lose leaves.
carpocapsa
Image - Wikimedia / Olei
La carpocapsa, whose scientific name is Cydia pomonella, is a moth that, in its larval phase, destroy the fruits by feeding on these. In addition, a hole in them can be easily distinguished.
To avoid losing the harvest, treatment with anti-caterpillar insecticides, such as this, From the first moment in which the fruits begin to develop with specific insecticides.
How is walnut cured?
The first thing to do whenever we find a walnut tree that seems to be bad is identify the problem, since if it has any pest or disease we will have to treat it with a suitable phytosanitary product. But besides that, it is very important that it is well cared for; that is to say, that it is necessary to ensure that it does not lack water or nutrients; Now, without going overboard, because if it is watered every day, for example, and the temperatures are mild, it is most likely that the roots will begin to die as a result of excess soil moisture.
But… there is still more. If we want it to have extra energy to better overcome the disease or plague in a shorter period of time, we recommend treating it with a liquid biostimulant for plants, such as No products found.. This is a product that will help your defenses to be somewhat stronger, so it is more than likely that you will recover without much problem.
Once the symptoms have disappeared, it will be very good to fertilize the walnut with a fertilizer rich in nutrients, such as guano, which can come from bats or seabirds, but which in any case is one of the best organic fertilizers most recommended for plants to grow healthy. you can buy it here.
Thus, your walnut tree will be beautiful again, for sure.