The term "Monilia" covers a variety of pathogens that primarily cause dreaded diseases in fruit trees, such as tip drought or fruit rot. This is how you can effectively identify and combat the fungi with home remedies and sprays.

Monilia is a difficult fungal infection to fight

Table of Contents

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  1. the essentials in brief
  2. Recognize Monilia
  3. root cause
  4. prevention
  5. combat
  6. frequently asked Questions

    7. the essentials in brief

    • 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 type of damage and pathogen, a distinction is made between fruit rot and peak drought.
    • Control is difficult if not impossible, which is why preventive measures are so important.

    Recognize Monilia - Typical symptoms and damage

    Dead shoots and twigs, withered flowers and browned, rotting fruit: Monilia disease occurs in various manifestations and is particularly feared by orchardists. However, it is not a single disease: instead, "Monilia" is the generic term for closely related fungal pathogens, some of which have specialized in different host plants and also cause different types of damage.

    A basic 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 rarely on pome fruit plants
    • Monilia fructigena: Also known as Monilia fruit rot or, due to the characteristic spore pattern, as upholstery mold, more commonly on pome fruit
    • Monilia linhartiana: occurs exclusively on quinces, causes damage to leaves, flowers and fruits

    In principle, all Monilia pathogens attack both pome and stone fruit plants, with certain preferences being discernible. However, there are no differences in terms of possible preventive and control measures. Drugs effective against peak drought also help against fruit rot and vice versa.

    Monilia peak drought

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

    If a plant is infected with the pathogen that causes peak drought, this is reflected in the following symptoms:

    • Affected flowers and adjacent leaves wilt 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
    • Death of the shoot tips as the disease progresses
    • Shoot tips dry up to a length of 20 to 30 centimeters
    • gradual bare tree crown
    • yellowish-grey spore deposits on dead twig tips
    • sometimes gum flow in areas between diseased and healthy wood

    The top drought is also sometimes referred to as twig monilia.

    Monilia fruit rot

    The Monilia fruit rot is very evident

    Fruit rots or fruit monilia are typically shown by rotting fruits:

    • first small brown, rotting spot
    • caused by damage to the fruit skin, for example by wasps or winder boreholes
    • these serve as a portal of entry for the pathogens into the fruit
    • rotten spot increases rapidly
    • Formation of characteristic circular spore pads
    • Fungus gradually colonizes the whole fruit, then the spores spread over the entire surface

    Fruit infected with fruit monilia is not edible and must be disposed of, but not in the compost! Otherwise the pathogen can take over and spread to other trees with the compost. Therefore, always throw rotten fruit and fruit mummies that have been removed from the tree in the household waste.

    digression

    Monilia black rot on apples

    A special feature of the Monilia rot occasionally occurs on apples, which is referred to as black rot. Apples infected late in the year often only begin to rot after harvest and during storage, turning completely black. In this case, however, spore camps are only rarely formed.

    root cause

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

    • the pathogen has overwintered in so-called fruit mummies
    • or withered shoots infected the previous year were not pruned

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

    Once it has landed on a fruit tree, the pathogen penetrates the twigs through the smallest of injuries or through the flower stalk and infects the flowers and shoot tips from there. These parts of the plant eventually dry up because the fungus clogs the drainage pathways and interrupts the flow of water. Peak drought infestation occurs primarily as a result of a rather cool and wet spring.

    The fruit monolia penetrates the apple from the outside

    The fruit monilia, on the other hand, develops because the pathogen penetrates the fruit through tiny injuries to the fruit skin and multiplies there. In this case, the infection does not occur in the spring, but at a later point in time when the fruit is developing and ripening.

    digression

    Which plant species are particularly endangered?

    In principle, all Monilia species occur on both pome and stone fruit plants. However, sour and sweet cherries and apricots are particularly susceptible to twig monilia or peak drought, while this disease rarely occurs on apple and pear trees. Instead, apples and pears are more frequently affected by fruit rot, as are quinces, plums and greengage and peaches. Cherries are also frequently attacked, with the popular 'Schattenmorelle' variety being particularly at risk. In general, some varieties are more susceptible, while others are downright resistant to infection.

    How to effectively prevent Monilia

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    Monilia is a very difficult infection to fight, which can only be controlled with targeted prevention. These include the following measures:

    location selection When planting, make sure that the location is as sunny, warm and airy as possible
    Suitable soil conditions Fruit trees that stand on heavy soil that tends to waterlogging are more likely to develop Monilia than trees and shrubs on loose, well-drained and humus-rich subsoil.
    Maintain plant spacing Be sure to keep the recommended planting distance and do not plant fruit trees too close together. This is the only way for the air to circulate and wet leaves and shoots to dry quickly after a downpour, for example. This reduces the likelihood of infection.
    clearing the crown The same as for the planting distance also applies to regularly thinning out the crown - a loose and not too narrow crown is less at risk of infection than one in which the shoots and branches are too narrow.
    fight pests Since fruit monilia in particular are often transmitted via certain pests such as the codling moth, you should definitely prevent an infestation (e.g. by painting the trunk white in autumn) or fight it with suitable measures.
    Strengthening of the immune system Strengthen the defenses of your fruit trees against fungal infections, for example by regularly spraying and/or watering with home-made manure. Onions, garlic and (field) horsetail have a very good preventive effect against fungi.

    You should start spraying the manure on the plants in the spring before they sprout and repeat the application at intervals of about two weeks during the vegetation period. Always use fresh plant manure.

    Plant resistant fruit varieties

    Another preventive measure is the planting of fruit varieties resistant to monilia. The following table gives you an overview of varieties suitable for the home garden:

    fruit type Resistant Varieties
    sour cherry 'Gerema', 'Carnelian', 'Corundum', 'Ludwigs Frühe', 'Merellenfeuer', 'Morina', 'Safir'
    sweet cherry 'Burlat', 'Regina', 'Summit', 'Sylvia'
    plum 'Hanita', 'Katinka', 'Tegera'
    peach 'Benedicte', 'Kernecht from the Promontory', 'Revita'

    There are currently no apple and apricots that are resistant or insensitive to Monilia (as of May 2022). In the case of apples, the focus of breeding is on resistance to other fungal diseases, and a corresponding research project has been running for apricots since 2022.

    Fight Monilia

    Monilia is an extremely stubborn disease

    "Since Monilia is difficult to combat, only targeted prevention helps with endangered trees."

    The main control measures against Monilia are:

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

    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 the spring.

    Which means you can inject against Monilia and when

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

    • Biological plant strengtheners: preventive treatment from the leaves shoot, repeat every ten days, spray directly into the flowers, suitable agent e.g. B. Neudovital
    • fungicides: preventive spraying at the beginning of flowering, when the flower is in full bloom and when it fades, also prevents an infection that is already beginning, suitable agents e.g. B. Duaxo Universal Fungus-Free or Fungus-Free Ectivo

    On the other hand, there are only a few remedies approved for the home garden to combat fruit rot. In the case of stone fruit, you can inject Obst-Mushroom-Free Teldor at the first sign of an infection;

    frequently asked Questions

    Can I add cut back branches infected with Monilia to the compost?

    No, please do not put infected clippings, rotten fruit or fruit mummies in the compost, but dispose of them with household waste or by incineration.

    Are there also types of fruit that are particularly at risk?

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

    How can my fruit tree become infected with Monilia in the first place?

    Infection occurs through spores that are carried from one infected tree to another by rainwater, wind, or insects. Trees that are already diseased, on the other hand, become infected again every spring via spore deposits on fruit mummies, in fallen fruit or on shoots and branches that have not been pruned back.

    tips

    Not only fruit trees are affected by Monilia, many ornamental trees can also be infected. This applies in particular to almond trees, ornamental apples and ornamental cherries.

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Care tips