Usually it is unfavorable locations that promote diseases, but not that the shrub is sensitive in any way, which unfortunately can no longer be said about boxwood these days. Some typical diseases of the Japanese spindle bush (Euonymus japonicus) and what you can do against them, we have summarized for you below.
Pay attention to changes in leaves and shoots in order to identify the disease and, if necessary, take appropriate action.
Powdery mildew
Although powdery mildew does not always cause the plant to die, it is still probably the most common disease. You can recognize them by the moldy gray spots that appear mainly on the upper sides of the leaves. The affected leaves sometimes turn yellow and may fall off, and deformations are also common in young leaves. However, the symptoms are not so severe that you have to fear complete baldness.
What is the cause?
A lack of ventilation, which causes moisture to build up around and within the plant, is the trigger for powdery mildew. To prevent mold from forming in the future, you should make sure that the Japanese spindle bush gets enough sun. If you cannot guarantee this by removing surrounding shade-casting plants, you may have to transplant the shrub yourself.
It is therefore important to maintain sufficiently large distances between the individual plants. This is especially important when planting a hedge.The right lightingpromotes ventilation within the shrub. Also try to water as close to your feet as possible, i.e. avoid wetting the leaves of the plant if possible.
What can you do if there is an infestation?
The first thing to do is to remove the infected plant parts and dispose of them in household waste (not in the compost, because then you can infect other plants). Furthermore, check the location and try to solve the problems described above that may be the cause. You can use chemical agents (fungicides) to combat them, but we recommend more environmentally friendly optionslike this. Home remedies should prove to be sufficiently effective if you also eliminate the triggers for the disease.
Identify, treat and prevent root goiter
This disease is caused by the bacterium Agrobacterium tumefaciens, which lives in the soil. If the plant is injured, it can infect it. The bacterium causes growths on the shoots of the shrub, which usually do not have a problematic effect on the growth of older plants. In young plants, the immune system is weakened more. If nothing is done to combat the infection, the shoot tips can no longer be adequately supplied, which not only slows growth but also leads to discoloration of the leaves and even the death of entire branches.
How to deal with this disease?
There is no cure for this disease. Instead, you can remove the parts with the growths on young plants. To do this, place the cut below this. The separated plant parts are destroyed. It is best to remove bushes that are severely affected completely. You can only avoid reinfection in other specimens if the plant is not injured, because the bacteria live in the soil for up to 2 years. During this period you should avoid cuts close to the ground. It is also very important to disinfect garden tools after each plant so as not to spread the disease to other plants. Do not plant any new plants in this soil for now.
Focal spot disease on evergreen shrubs
The focal spot disease (Anthraknose) is a fungal disease that you can recognize when small, brown spots appear on leaves and twigs that are light in the middle. There may also be cracks in the leaves. The disease must be taken seriously because it can cause major leaf loss. The spread of the fungus is facilitated by the weather in spring and not by incorrect care on your part: If the spring is permanently wet and cool, the fungus feels comfortable and causes mischief.
What is being done?
Anything infected will be immediately removed and destroyed. This applies not only to the parts of the plant that are still on the bush, but also to those that have already fallen off. If the infection is still in its early stages, with a bit of luck you may be able to save it. However, it is more likely that there is nothing you can do because effective remedies for the disease are not permitted in Germany. Therefore, it is best if you dispose of the plant completely. Even then, not a single part of the plant remains in the bed.
The characteristics of Cercospora leaf spots
The name already suggests that this disease is caused by a fungusDestructive cercosporais caused, but sometimes also byCercosporaeuonymi. Either way, you can recognize the infestation by the brown spots on the leaves, which have an irregular shape. The spots can be of different sizes and over time merge into one another until the entire leaf turns brown. Their center is grey-brown and the surface is slightly rough because so-called fruiting bodies form there.
What control methods are there?
What sounds a little frightening at first is actually not that fatal for the plant. Dispose of infected plant parts as quickly as possible (including those that have already fallen off), which usually stops the spread and saves the plant. If the fungal infestation is already more severe, the only solution may be to dispose of the plant, as suitable fungicides are either not permitted or have little effect because the fungi have developed resistance.
Treat scabs
The disease is caused by the fungusElsinoe euonymi-japonites, which causes brown to light spots on leaves and twigs. The edges are also rusty brown in color and are usually slightly curved. As the infection progresses, the spots merge into one another. The fungi disrupt photosynthesis and damage plant cells.
Fight the fungus correctly:
In general, you proceed with this prickly infection in the same way as with the leaf spot disease mentioned above: Remove diseased parts of the plant and from the soil and destroy them. If the plant is already more severely infected, you can use fungicides, making sure that they are approved for use in the garden. Beforehand, you can try an agent containing copper, which usually has enough effect.
What alternatives to boxwood are there?find out here.
Conclusion: Robust and easy to care for despite possible illnesses
We would like to emphasize once again that the Japanese spindle bush diseases mentioned above, although possible, are relatively rare and you should not be deterred by them. In general, the shrub is very robust and resilient and is therefore the perfect alternative to some other, more sensitive specimens. The most likely disease, if any, is powdery mildew, but this is usually easy to treat and prevent.
