Recognize and fight the fungal disease

the essentials in brief

• at Monilia are plant diseases caused by a closely related group of fungi.
• Stone and pome fruit plants, especially sweet and sour cherries, are particularly at risk.
• Depending on the damage and pathogen, a distinction is made between fruit rot and tip drought.
• Control is difficult if not impossible, which is why preventive measures are so important.

Recognizing Monilia - Typical symptoms and damage

Dead shoots and twigs, dried up flowers and browned, rotting fruits: The Monilia disease comes in a variety of forms and is particularly common among orcharders feared. However, it is not a single disease: Instead, "Monilia" is the generic term for closely related ones fungal pathogens, some of which have specialized in different host plants and also different types of damage cause.

Basically, a distinction is made between three pathogens and thus forms of Monilia:

• Monilia laxa: causes the so-called peak drought, usually the flowers are infected first, often occurs on stone and more rarely on pome fruit plants
• Monilia fructigena: also called Monilia fruit rot or, due to the characteristic spore pattern, called upholstery mold, more common on pome fruit
• Monilia linhartiana: occurs only on quinces, causes damage to leaves, flowers and fruits

Basically, all Monilia pathogens infect both pome and stone fruit plants, whereby certain preferences can be determined. However, there are no differences in terms of possible measures for prevention and control. Means effective against peak drought also help against fruit rot and vice versa.

Monilia peak drought

If a tree is attacked by the Monilia peak drought, the flowers wither within a few days

If a plant is infected with the causative agent of the peak drought, this is indicated by the following symptoms:

• Wilted flowers and neighboring leaves within a few days
• Browning of flowers and leaves
• Infested parts of the plant do not fall off, but remain dried up on the plant
• The shoot tips die off as the disease progresses
• Shoot tips dry up over a length of 20 to 30 centimeters
• gradual balding of the treetop
• yellowish-gray spore beds on dead branch tips
• sometimes rubber flow in areas between diseased and healthy wood

The peak drought is also sometimes referred to as the branch monilia.

Monilia fruit rot

The Monilia fruit rot can be seen very clearly

Fruit rot or Fruit monilia typically show up as rotting fruits:

• initially a small brown, rotting stain
• arises from damage to the peel of the fruit, for example from wasps or winder drill holes
• these serve the pathogens as a gateway into the fruit
• putrid spot enlarges quickly
• Formation of characteristic circular spore pads
• Fungus gradually colonizes the whole fruit, then the spores spread over the entire surface

Fruits infected with fruit monilia are not edible and must be disposed of, but never on the compost! Otherwise, the pathogen can think twice and spread to other trees with the compost. Always throw rotten fruit and fruit mummies removed from the tree in the household waste.

Digression

Monilia black rot on apples

root cause

Both twig and fruit monilia are caused by certain closely related fungi. The infection occurs in the branch monilia in early spring, for example because

• the pathogen overwintered in so-called fruit mummies
• or dried up shoots infected in the previous year were not cut back

Fruit mummies are mostly dried up fruits that either hang on the tree over the winter or fall to the ground and remain there. With rising temperatures in spring, not only do the trees sprout, the fungi also form new spores. These spread through wind, rain and insects (e. B. in the course of pollination) on endangered woody plants.

Once landed on a fruit tree, the pathogen penetrates the branches through the smallest injuries or through the flower stalk and infects flowers and shoot tips from there. These parts of the plant eventually dry out because the fungus clogs the ducts and interrupts the flow of water. An infestation with the peak drought occurs mainly as a result of a rather cool and humid spring.

The fruit monolia penetrates the apple from the outside

The fruit monilia, on the other hand, occurs because the pathogen penetrates the fruit through tiny injuries to the fruit skin and multiplies there. Here the infection does not take place in spring, but at a later point in time when the fruit is developing and ripening.

Digression

Which plant species are particularly endangered?

How to effectively prevent Monilia

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Monilia is an infection that is very difficult to control and can only be brought under control with targeted prevention. Above all, this includes these measures:

You should start spraying the plant manure in the spring before budding and repeat the application every two weeks during the growing season. Always use fresh vegetable manure.

Plant resistant fruits

Another preventive measure is the planting of fruits that are resistant to Monilia. The following table gives you an overview of the varieties that are suitable for the home garden:

There are currently no apples and apricots that are resistant or insensitive to Monilia (as of May 2020). In the case of apples, the focus of the cultivations is on resistance to other fungal diseases; a corresponding research project has been running for apricots since 2018.

Fight Monilia

Monilia is an extremely persistent disease

The main control measures against Monilia are:

• Timely cut back: The peak drought can be limited by cutting back the diseased plant parts deep into the healthy wood. Cut visibly diseased branches and shoots up to approx. 30 centimeters away - at any time of the year, not just after the harvest.
• Removal of rotting fruits and fruit mummies: Do not leave rotting fruits hanging on the tree, but remove them immediately and dispose of them with household waste. The same applies to fruit mummies, which under no circumstances should be left on the tree over the winter months. Also remove any windfalls.

Otherwise there are no direct control measures, because once Monilia has broken out, spraying with a fungicide will no longer help. These agents only have a preventive effect and must be applied in spring.

Which means you can inject against Monilia and when

The following overview shows you which fungicidal agent you can spray against the branch Monilia and when:

• Organic plant strengtheners: preventive treatment from leaf shoots, repeat every ten days, spray directly into the flowers, suitable agent e.g. B. Neudovital
• Fungicides: preventive spraying at the beginning of flowering, at full bloom as well as with fading, also prevents an already beginning infection, suitable means z. B. Duaxo universal mushroom-free or mushroom-free Ectivo

On the other hand, there are only a few remedies for fruit rot that are approved for the home garden. In the case of stone fruit, you can inject Fruit-Mushroom-Free Teldor at the first signs of infection. B. Atempo copper-fungus-free), which is also used against scab.

frequently asked Questions

Can I put pruned twigs infected with Monilia on top of the compost?

No, please do not put infected cuttings as well as rotten fruits or fruit mummies on the compost, but dispose of them with the household waste. by burning.

Are there also types of fruit that are particularly endangered?

Sweet and sour cherries are particularly endangered by Monilia, with the 'morello' variety being very susceptible. In principle, however, almost all fruit trees can be attacked.

How can my fruit tree get infected with Monilia at all?

Infection occurs through spores that are transferred from one infected wood to another by rainwater, wind or insects. On the other hand, trees that are already diseased are infected anew every spring via spore beds on fruit mummies, in fallen fruit or on shoots and twigs that have not been cut back.