Plant diseases

Cypresses - Detect and fight diseases and pests


The cypress is an undemanding plant, but its maintenance errors can be very difficult. The plant is also not immune to pests. Basically, intervene immediately to protect the plant.

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The cypress (Cupressus) is formative for Mediterranean landscape forms and determines the landscape in Tuscany and other Mediterranean regions. The evergreen trees have different growth forms and are characterized by rapid and lush growth.

Some types of cypress are true survivors and also grow in dry and rough mountain regions. The cypresses found in Central Europe outdoors or in buckets also prove to be quite undemanding. If diseases and pests occur, quick action is required so that the plant can be preserved. Preventive measures can also be taken so that the joy of the plants that provide Mediterranean charm is not spoiled.

It's easy - take good care of cypresses

The cypress is an undemanding plant and also suitable for the rather inexperienced hobby gardener. A sandy, humus-rich soil provides the preferred site conditions. The biggest maintenance mistake is inadequate irrigation. The plant needs sufficient water not only in hot summers, but also in winter.

Elixir of life water

Regular watering is essential for the cypress. The water requirement increases when the plants get a drafty location. The wind leads to increased dry soil. This can be counteracted by applying a mulch layer. Hardy cypresses withstand cold temperatures, but die of thirst if not watered enough.

" Tip: Container plants protect a drainage layer made of pottery shards or pebbles from dreaded waterlogging.

Krankheiten Possible diseases of cypress trees

Brown spots

If cypresses are not watered enough, brown spots will quickly appear. If the brown spots increasingly show up in spring, this is mostly due to a too dry winter level. If there are brown spots, the plant should be examined more closely, because fungal infections or pest infestation can also be noticed by brown spots.

Attention: Brown spots on cypresses will not go away through increased watering. A radical cut back cannot be avoided.

Fungal infection

Brown spots on cypress trees can also indicate a fungal infection. This is particularly often the case if the brown spots continue from the inside to the tips of the shoots. Now quick action is required. It is important to find out the type of fungus and to take appropriate measures to combat it.

"Phytophthora cinnamomi - danger to the roots

In addition to cypresses, this type of fungus also affects juniper, thuja, azaleas or rhododendrons. More than 900 different types of plants belong to the host of this soil-borne mushroom. The cypress is infected via the root, which initially goes unnoticed. The fungus spreads preferably at summer temperatures above 25 degrees. Sufficient moisture also favors the germination of the spores. The fungus grows rapidly within the plant. Brown spots appear and individual shoots begin to die.

Attention: There is a possibility of confusion with the Thujaminmoth or the Juniperminiermoth.

Diseased plants should be removed immediately. If the cypress is dug up, the fungal infection can be recognized by the brown discolored root ball.

What can be done preventively?

❶ Avoid waterlogging
Böden loose floors
Legen Lay drainage
❹ administration of plant strengthening agents

"Kabatina Thujae - danger for cypress trees

This fungus not only affects the eponymous tree of life, but also occurs in Leyland cypresses. The appearance of the micro-fungus favors a nutrient-poor soil. A lack of magnesium and calcium in particular can contribute to fungal infections. Infested cypress trees can be recognized by the yellow-brown discoloration of the needles. The bark shows a strong browning on infested shoots. The formation of black pustules also indicates infested shoots. The pustules may also break open at a later stage.

What measures are required?

❶ Remove infected plant parts
❷ Thinning of plant stands too dense
❸ pay attention to a balanced supply of nutrients
❹ Control of the fungus with Ortiva, Dithane or other fungicides

❍ Pest attack on cypress trees

The otherwise quite undemanding cypress can occasionally be attacked by pests.

The main problem with cypresses is pest infestation of:

  • leafminer
  • Bark beetle or mealybugs appear.

Miniature moths - plant danger in a double pack

Mock cypresses can be infested by the juniper moth or the thujamin moth. Both species are small butterflies about five millimeters in size, reminiscent of moths. Differences are to be found in the life cycle of both types.

In both species, the eggs are laid in the leaf scales of the plants. After hatching, the larvae burrow into the tips of the shoots and begin to hollow them out. In said periods, the pest infestation can easily be determined by shaking the plants. Then a short laying on of the moths can be observed. On closer inspection, the infestation is also evident from the brown discoloration of the shoot tips. Damaged branches are hollowed out inside and black crumbs can be seen, these come from the excretions of the moths.

Attention: Fungal infestation also shows similar signs, however plants damaged by fungi are not characterized by hollowed-out shoots.

Infestation with leaf miner is usually coped well with healthy and regularly cut plants. If the infestation is particularly large, commercially available preparations against biting insects can be used. The foliage, which is infested with larvae, is cut out generously. The waste should not end up on the compost. Stow the infected plant parts airtight in plastic bags and dispose of them with household waste.

The plant can be covered for prevention. The trade offers pheromone traps. These attract males willing to mate, which get caught in the adhesive traps. Although these traps are not 100% protection against pest infestation, they provide information about whether an infestation is indicated and how high a possible risk is. The hobby gardener can take appropriate countermeasures at an early stage. The traps should be left in the plants until autumn, because the pests provide for three to four times a year.

If the traps indicate an infestation, quick action is required:

❶ Remove plant parts already affected
Kontrollieren check the plant regularly
❸ Burn infected leaves or dispose of them airtight
❹ Cover the plant with a fine mesh

Bark beetle - death blow for cypresses

Bark beetles pose the greatest threat to cypresses in our gardens. In late spring, the black beetles, which are only around two millimeters in size, begin to hatch. First the bark beetle satisfies its hunger on the young shoots.

This so-called ripening shows up on brown shoots of different lengths, which appear kinked. The causes are often found at the kinks. This damage pattern can easily be mistaken for a shoot death of the plant due to insufficient watering or frost damage after winter.

After ripening, the eggs are laid in the bark of the plants. After hatching, the larvae create extensive feeding channels. The entire plant dies. The holes about the size of a pin head can be seen on the branches. If the bark is cut, the feeding channels created by the larvae are clearly visible. The bark beetle can destroy entire forest stands. It is hopeless to take action against the bark beetle in the garden at home. Infested plants should be removed immediately.

How do you recognize the bark beetle infestation?

  • Drilling powder at the end of the trunk
  • Cypresses lose their bark
  • brown branches
  • The entire plant dies

Cypress cancer

Cypress cancer is caused by fungal infections. Affected plants can be recognized by the striking yellow and red coloring of the branches. The branches dry up at a later stage. The bark also shows discoloration and breaks open at a later stage of the disease. Spreading the fungus is favored by rain and wind. Plants that are particularly drafty or have injuries are particularly susceptible.

What should I do?

❶ Completely remove infected plant parts
❷ Supply interfaces with benzimindazoles
❸ Disinfect all tools used with alcohol

How can diseases and pests of cypresses be avoided?