Brown rot is one of the most destructive diseases of stone fruits, such as peach, nectarine, apricot, cherry and plum. Major losses can occur especially during postharvest storage.
Life cycle and appearance of Monilinia
Monilinia overwinter as mycelium in fallen, infected fruit or in shoot tumours. Conidian (spores) that have formed in the tumours infect the crop in the spring. Monilinia spp. are able to infect various plant organs, causing blossom blight, twig blight, and brown rot in immature and mature fruits. Of all these organs, the mature fruits are the most sensitive phase. Perforations or small cracks on fruits caused by hail, birds or mechanically during harvest are the main points of entry for Monilinia, but some Monilinia species are also able to penetrate through natural openings like stomata. Losses depend on weather conditions and are especially severe if high humidity, warm temperatures and abundant rainfall prevail prior to harvest.
Symptoms on ripening peaches and nectarines may first appear as small, circular spots that enlarge or coalesce. On mature fruit, these lesions develop and enlarge rapidly. When environmental conditions favour disease development, ripe fruits may completely rot within two days.
Monilinia rot occurs in all types of fruit, but mostly stone fruit such as peach and cherry as a rule, rather than apple and pear.
How to prevent Monilinia rot
Keeping the premises clean and regularly removing the infected fruit is the most important measure to prevent further contamination. Stored fruit needs to be regularly inspected for Monilinia. Infected fruit has no shelf life and infects surrounding fruit. It’s important to remove infected fruit as soon as possible. The infection can spread to healthy fruit and the whole crate can start to rot within a short time. The relative long period of incidence, extending from bloom to postharvest, can result in the build-up of disease pressure during the growing season. With a regular (integrated) preventive spraying schedule, an increase in the disease pressure can be controlled during the cultivation and ensures that less infection occurs during the storage period.
- During the winter pruning remove the present pupae and burn them
- Destroy the infected fruit during the ripening and harvest time
- Use preventive fungicides like Noli
- Removing the fallen fruit is strongly recommended to limit the spread of Monilinia fungus for the following season
- Prevent damaging fruit during harvest
- Stored fruit needs to be inspected for Monilinia regularly and removed immediately if infected.