The monilia , also known moniliosis , rot brown or mummified is a disease that produces significant losses in stone fruit .
Monilia spp especially affects stone fruit trees ( cherry , nectarine , apricot , peach , plum , almond …). Although it can also affect pome fruit trees such as apple or pear .
At present, four species of Monilia spp are described : M. laxa , M. fructigena , M. fructicola and M. polystroma .
In Europe we mainly find Monilia Laxa, which mainly affects stone fruit trees and Monilia fructigena, which affects seed fruit trees more .
Monilia fructicola was not detected in Spain until 2009. The peculiarity of this fungus is that it produces apothecia (“ lichens ”) that act as a primary inoculum. It is feared that its expansion will be rapid and will end up displacing the other strains.
Cycle and development of Monilia Spp
The ideal conditions for the development of the Monilia occur during the spring .
Contact with rain , high relative humidity and mild temperatures ( 23-25ºC ) promote the development of the disease. If the conditions are favorable, some fruits will be affected in spite of the realization of treatments. However, if treatments are not carried out it is possible to lose the harvest completely.
Although these conditions are optimal, the fungus can develop in a temperature range between 5 and 30 ºC.
The moniliosis inoculum overwinters on mummified branches , shoots, and fruits in spring. These infection points release spores or conidia in early spring.
They infect the flowers through the stigma. The fruits are especially affected during the ripening phase.
The fruit with injuries ( bite fly , rajas rain, hail, suzukii drosophila ) is especially susceptible to infection, but later the fungus can spread by contact.
Due to their good expansion capacity by contact between fruits, the most productive varieties of fruit trees tend to suffer the incidence of the disease to a greater extent.
During the marketing phase, if the fruit is exposed to high humidity conditions (condensations due to changes in temperature, high relative humidity …) the Monilia can attack with virulence and cause significant losses .
Damage caused by Monilia
The damage caused by the fungus Monilia Spp is very considerable. These damages can begin with flowering and extend to the fruits both in the field and in the chamber.
Producers and distributors of fruit must strive to apply treatments and seek new control techniques .
During rainy springs it is common for the fungus to infect cherry blossoms or other crops. The flowers dry out, necrotize and bunch up , remaining firmly attached to each other.
-The mummification of the flowers produces a decrease in the fruit set and reduces potential harvest . This usually happens when it rains several times during flowering. The level of incidence may be reduced with the application of fungicides before flowering.
If the climatic conditions allow it, Monilia spp, continues to spread reaching the zone of beginning of the outbreak (buds). This produces a canker at the tip of the flower bud that, if generalized to the rest of the buds, completely dries the bud.
-The Monilia weakens the fruit trees and produces the loss of productive shoots.
Studies carried out in Spain during 2010 indicate that Monilia Laxa accounted for more than 80% of infections in stone fruit.
The damages produced in the fruit are the ones with the greatest repercussion.
– Reduction of production .
– Increase in collection costs (greater difficulty in selection).
– Commercial depreciation of the fruit (the storage time in the chamber is reduced).
Cultural control and applications of treatments against Monilia
Cultural measures and treatments against Monilia are necessary to prevent and control Monilia in fruit trees .
They should be aimed at reducing the presence of Monilia foci (inoculums) on the crop.
During pruning cherry should eliminate are the branches affected and the mummified fruits . The remains of pruning and fruits with the presence of monilia must be eliminated (burning is a good option).
They favor infection : excessive pruning, nitrogenous fertilizers and excess watering.
They reduce the probability of infection : green pruning, crown thinning.
Nurseries must ensure that the shoots used for grafting are free of the fungus.
Chemical treatments for the control of Monilia Spp
The application of two annual cupric treatments is recommended (admitted in organic farming ).
We will do one in autumn at leaf fall and another before the fruit trees come out of winter rest. This considerably reduces the inoculum load of Monilia Spp existing in the plantation, helping to control other fungi such as anthracnose or screening .
The fungicide treatments are authorized after petal fall , before can adversely affect bee populations of beneficial insects and pollinators.
In cherry this treatment is usually carried out together with insecticides to control aphids .
A treatment with systemic fungicides should be carried out after petal fall and additional weekly treatments when rains occur or are expected.
In the case of cherries, when cracking occurs, infection is very likely despite the appropriate control treatments.
WARNING : To avoid the creation of resistance, they must alternate treatments with different authorized active substances .
In winter, the application of urea treatments is recommended to help decompose organic matter and favor the fall of the infected leaves to the ground.
Resistance of cherry varieties to Moniliosis
Each cherry variety presents a different response to infection by Monilia sp. Although they are not completely resistant if there are important differences between varieties.
Cherry varieties resistant to Moniliosis : Larian , Regina , Hedelfingen , Black Star .
Monilia sensitive cherry classes : Canada Giant , Garnet , New Star , Summit , Van , Lapins , Celeste and Sunburst .