Wrong care makes Korean firs susceptible to diseases and pests. We will show you how to recognize them and how to treat them correctly.
Korea firs (Abies koreana) usually get along very well with our climate and are considered robust and not very susceptible plants. At home in the mountain forests of South Korea, the plant also copes very well with a rather harsh climate and survives the winter outdoors without protective measures. Nevertheless, the occurrence of diseases and infestation with pests cannot be completely ruled out. The hobby gardener is often not entirely innocent of this, because mistakes in care can also weaken the plant and thus promote the appearance of damage. Find out now which diseases and pests can occur, how you can recognize them in good time and counteract the infestation effectively.
Mealybugs
Mealybugs live up to their name and the infestation is easy to see with the naked eye. The shoots and needles are covered with a light woolly covering that is reminiscent of cotton wool. Depending on the severity of the infestation, the coating can be visible as small dots or as a large area over the entire plant. If there is also a greyish coating on the needles of the Korean fir, then the plant is also affected by sooty mold. Unfortunately, this is quite common, because the fungus lives on the excretions of mealybugs.
Effective fight against mealybugs
Mealybugs can be combated naturally by meticulously collecting the pests. You should proceed carefully, because if only a few animals are forgotten, the damage is not repaired. Soapy water, which you should spray regularly over the affected parts of the plant, is also quite effective against mealybugs. Lacewings and parasitic wasps are natural predators.
Tip: You only need to fight mealybugs effectively. Once you have succeeded, the sooty mold will also disappear, as the fungus has been deprived of its food base.
The trade also offers chemical pesticides. However, you should only consider this as a last resort. When applying, strictly follow the instructions on theFacts mentioned in 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 on their cell sap.
To combat bark lice, it is usually sufficient to regularly treat the plant with a hard jet of water. A decoction of fresh nettle leaves can also help against infestation with bark lice.
Tip: You can also reduce the infestation by removing heavily infested shoots.
Targeted elimination of gray mold
Grey mold rot can be prevented by species-appropriate care. If the plant receives a permeable soil, it can develop optimally and will be less susceptible to diseases. Gray mold also occurs when the trees are not airy enough and are planted in a row with other plants, for example. The fungus Botrytis cinerea is responsible for the disease.
If the plant is affected by gray mold, the young shoots in particular will die off more often. Cut out the affected parts of the plant generously. The fungal infestation is difficult to treat with home remedies and if the infestation is severe, it will usually be necessary to resort to 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 he alth.
Help, brown needles
If the Korean fir develops brown needles, this can have various causes. There is usually a deficiency. Exactly where the defect is to be found needs to be examined more closely. If the needles appear yellow at first and turn reddish brown over time, there is a potassium deficiency. If yellow discolouration appears, especially on older needles, the Korean fir is probably lacking in magnesium.
Tip: Too dark a location or too heavy a soil can also lead to discolouration of the needles.
A soil analysis will give you certainty. Then you will find out exactly which nutrients the plant is missing and can counteract this with appropriate fertilization. Soil that is too heavy must be loosened up and made more permeable with sand or gravel. Only transplanting the Korean fir helps against a location that is too dark.
Help, Needle Drop
If the Korean fir sheds its needles, the same applies as for discoloration of theneedles described. If the plant has been suffering from various deficiency symptoms for a long time, it is not uncommon for the Korean fir to become 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. Although Korean firs require comparatively few nutrients, magnesium deficiency can still occur. Therefore, rely on a complete fertilizer with a high magnesium content.
Waterlogging makes Korean firs suffer
The pines do not tolerate waterlogging. Waterlogging occurs when the water cannot drain away and attacks the roots. The plant can then no longer absorb sufficient nutrients. If waterlogging in the soil remains undetected, this can lead to the death of the plants.
How to prevent waterlogging when planting outdoors
When planting, it is important to loosen the soil well. Heavy, loamy soils are not suitable for the plants and should always be made more permeable with sand or coarse gravel. As a result, the soil loses compactness and the irrigation water can drain off better.
Tip: Avoid underplanting the Korean fir. This promotes soil compaction.
Remove vegetation around the Korean fir regularly. By creating a watering rim, the plant can absorb the water better. If you mulch regularly, the soil will dry out less quickly.
How to prevent waterlogging when keeping buckets
Here, too, precaution begins with the planting. Choose a planter that has adequate drainage holes in the bottom for liquid.
Tip: If the plant is in the cachepot, the irrigation water should be removed regularly.
An effective measure against waterlogging is the installation of a drainage. To do this, lay out coarse gravel or clay granules on the bottom of the planter before you fill up the potting soil. This makes it easier for the irrigation water to drain away.
Avoiding diseases through proper care
Select location
The Korean fir does best in a bright and semi-shady location.A solitary position is recommended for larger varieties.
The plants also thrive in sunny locations, but then they need more water.
Soil quality
A loose and permeable soil is important for the Korean fir.In a heavy soil, the delicate roots cannot spread and the plant cannot be supplied with sufficient nutrients.
Watering and fertilizing
The substrate should not dry out completely.Avoid waterlogging.
If possible, irrigate with rainwater instead of tap water.
Fertilization is usually not necessary.
Brown needles can indicate a magnesium deficiency.