Incorrect care makes Korean firs susceptible to diseases and pests. We will show you how to recognize and treat them correctly.
Korean firs (Abies koreana) usually get along very well with our climate and are considered robust and less susceptible plants. At home in the mountain forests of South Korea, the plant copes very well with a rather harsh climate and survives the winter outdoors without protective measures. Nevertheless, the occurrence of diseases and pest infestation do not fail to materialize. The hobby gardener is often not entirely innocent of this, because maintenance errors can weaken the plant and thus promote the occurrence of damage patterns. Now find out which diseases and pests can occur, how to recognize them in good time and how to counter the infestation effectively.
Mealybugs live up to their name and the infestation is clearly visible to the naked eye. The shoots and needles are covered by a light, wooly covering that makes you think of cotton wool. Depending on the intensity of the infestation, the covering can become visible as small dots or can be drawn across the entire plant as a large-scale mark. If there is also a grayish coating on the needles of the korea fir, then the plant is also infested with soot thaw. Unfortunately, this happens quite often, because the fungus lives on the excretions of the mealybugs.
Combat mealybugs effectively
Mealybugs can be controlled naturally by meticulously collecting the pests. You should do this carefully, because even a few animals are forgotten, the damage is not remedied. Soapy water is also quite effective against mealybugs, which you should spray regularly over the affected parts of the plant. Lacewings and parasitic wasps are considered natural predators.
Tip: You only need to fight the mealybugs effectively. If you have succeeded in doing this, the soot dew will also disappear, since the food base has been removed from the fungus.
The trade also offers chemical pesticides. However, you should only consider this as a last resort. Use strictly according to the facts given on the instructions for use, because it is poison.
Treat bark lice effectively
Bark lice are only a few millimeters in size and therefore difficult to see with the naked eye. The pests mainly attack larger coniferous plants and live from their cell sap.
To control the bark lice, it is usually sufficient to regularly treat the plant with a hard water jet. A brew of fresh nettle leaves can also help against bark lice.
Tip: You can also reduce infestation by removing heavily infested shoots.
Eliminate gray mold rot
The gray mold rot can be prevented by appropriate care. If the plant receives a well-drained soil, it can develop optimally and will be less susceptible to diseases. Gray mold rot also occurs when the trees are not airy enough and, for example, are planted in a row with other plants. The fungus Botrytis cinerea is responsible for the disease.
If the plant is affected by gray mold rot, the young shoots in particular will increasingly die off. Generously cut out the affected parts of the plant. Fungal infestation is difficult to treat with home remedies, and if there is more infestation, it will usually be necessary to use chemical agents. Here too, it is important to follow the manufacturing instructions carefully so that other plants are not damaged and there is no risk to your own health.
Help, brown needles
If the Korean fir gets brown needles, this can have different causes. As a rule, there is a deficiency symptom. Exactly where exactly the defect is to be found has to be examined. If the needles initially appear yellow and turn reddish brown over time, there is a potassium deficiency. If older needles show yellow discolouration, the korea fir is probably lacking in magnesium.
Tip: If the stand is too dark or the floor is too heavy, the needles may become discolored.
A soil analysis gives you certainty. Then you will find out exactly which nutrients are missing from the plant and can counteract them with appropriate fertilization. Soils that are too heavy need to be loosened and made more permeable with sand or gravel. If the location is too dark, only moving the Korean fir will help.
Help, needle drop
If the Korean fir throws off its needles, the same applies as described for discoloration of the needles. If the plant has suffered from various deficiency symptoms for a long time, it is not uncommon for the korea fir to be bald. Here, too, it should first be checked whether the Korean fir receives sufficient moisture and whether the soil does not appear too heavy and impermeable. Korea firs require comparatively little nutrients, but magnesium deficiency can still occur. Therefore, rely on a complete fertilizer with a high magnesium content.
Waterlogging makes korea firs suffer
The pine plants do not tolerate waterlogging. Waterlogging occurs when the water cannot drain and attacks the roots. The plant can then no longer absorb enough nutrients. If waterlogging remains undetected in the soil, this can cause the plants to die.
How to prevent waterlogging when planting outdoors
When planting, it is important to loosen the soil well. Heavy, loamy soils are not suitable for plants and should in any case be made more permeable with sand or coarse gravel. As a result, the floor loses its compactness and the irrigation water can drain away better.
Tip: Avoid underplants of the Korean fir. This favors soil compaction.
Remove the vegetation around the Korean fir regularly. The plant can absorb the water better by applying a watering rim. If you mulch regularly, the soil dries out less quickly.
This will prevent waterlogging in the bucketConiferous plants in the planter -
Here, too, precaution begins with planting. Choose a planter that has sufficient drain holes for liquid in the soil.
Tip: If the plant is in a planter, the irrigation water must be removed regularly.
An effective measure against waterlogging is to create a drainage. To do this, lay out coarse gravel or clay granulate on the bottom of the planter before filling up the soil. This facilitates the drainage of the irrigation water.
Avoid diseases through proper care
Site selectionThe Korean fir best gets a bright and partially shaded location.
The unique position is recommended for larger varieties.
The plants also thrive in sunny locations, but then require more water.
Soil qualityA loose and permeable soil is important for the Korean fir.
In a heavy soil, the delicate roots cannot spread and do not provide the plant with sufficient nutrients.
Watering and fertilizingThe substrate should not dry out completely.
If possible, water with rainwater instead of tap water.
Fertilization is usually not necessary.
Brown needles can indicate magnesium deficiency.