Here you can find out everything about Monilia: How to recognize the damage, prevent the fungus and fight it. Information on home remedies and sprays.
How to recognize a Monilia/Spike Drought infestation
Monilia is a very unwelcome visitor to the orchard. The pathogen can not only cause great damage, but also attack a large number of fruit trees. These include the sour cherry, sweet cherry, quince, plum, apple, apricot, pear and peach. Many sour cherry varieties in particular are considered to be extremely susceptible to the pathogen, whereas the disease rarely occurs on apple and pear trees. The dreaded peak drought caused by Monilia pathogens can appear shortly after flowering. First, flowers and leaves wilt at the tips of the branches, but do not fall to the ground and remain dried up on the branches. After a short time, the shoot tips of the affected branches also dry up and die off. Sometimes yellowish-grey spore beds from the monilia fungus can also be seen. In the case of a severe infestation over several years, the entire tree crown can be bare. Incidentally, the same pathogen is also responsible for monilia fruit rot. However, the fruit can only be infested if the plant has already been damaged - for example by the feeding activity of a codling moth. Initially, the fruits only have a small brown spot on the damaged fruit skin, but after a very short time the fruits rot completely and form ring-shaped mould. This can result in fruit mummies that get stuck in the fruit tree or the spoiled fruit can fall to the ground.
The monilia fungus
Strictly speaking, not only one fungus is responsible for the peak drought. The unwelcome fungus can either be Monilia fructigena, Monilia laxa or for quinces Monillia inhartiana. For the hobby gardener, however, it doesn't matter which fungus representative it really is. In order for the peak drought to break out, Monilia has to infect the affected fruit tree through the open blossoms. Especially in cool and wet weather during the flowering periodincreased fruit trees infected by the harmful fungus. Monilia then grows from the flower into the tips of the branches. There the water supply for the shoot tips is interrupted and the characteristic dry tips develop. Insects, wind and rain all help to spread the fungal spores. The very fungal spores that triggered peak drought are also capable of triggering monilia fruit rot. Even the tiniest mechanical damage to the fruit skin is enough for this, and the spores of Monilia can quickly grow into the apple or cherry.
Prevent Monilia
The best preventive measure against Monilia is, as so often, the choice of variety. For example, the susceptible sour cherry variety 'Schattenmorelle' can be replaced with the more resistant varieties 'Morellenfeuer' or 'Gerema'. Most of the other types of fruit also have resistant varieties. It is best to find out more directly from your local specialist retailer. It also always makes sense to design the crowns of fruit trees in such a way that a lot of air can circulate between the branches and moisture dries off quickly. Unfortunately, fungi are particularly good at penetrating plant tissue through cuts. Larger wounds, such as those caused by removing an old branch, should be closed with tree wound balm. In general, cutting should only be carried out in dry weather. In addition, spraying biological tonics such as horsetail or algae preparations can prevent peak drought from occurring. The preparation does not act directly against the monilia pathogen, but strengthens the general defenses of the fruit trees through an ideal supply of nutrients.
Fighting Monilia
All diseased branches should immediately be cut back deep into the he althy wood and destroyed. The fungus has often penetrated much further into the wood and should therefore be cut 20 cm deep into the he althy wood. When infested after flowering, Monilia fungi often trigger fruit rot with the typical brown-grey fungus lawns. The infected fruits later dry up and become so-called fruit mummies, in which spores of the fungus overwinter on the tree or on the ground and spread from there again the next year. Here it is particularly important to collect the diseased fruits, otherwise he althy fruits will be infected. Under no circumstances should they be thrown on the compost, because the fungus can still spread its spores wonderfully theremultiply. Peak drought can only be combated before it breaks out if the pathogen has not yet penetrated the blossoms to the tip of the branch. Treatment should be done during flowering to be most effective. So if damp and cool weather is announced, an infestation is particularly likely. If you then want to protect your fruit trees effectively, unfortunately only chemicals can help. Before this is used, however, all preventive measures should be exhausted. Copper agents are suitable as a biologically usable fungicide. In an emergency, these can also be used after the visible infestation. The first spraying is done when the first flowers open and the second in full bloom. The third spray is not always necessary and should be carried out towards the end of flowering.
In addition to the Monilia fungus, fungal pathogens Phytophthora infestans are also feared by gardeners. We explain how to recognize and combat the fungus.