If worms are found in cherries, they are usually the larvae of the cherry fruit fly (Rhagoletis cerasi). There are various methods to prevent an infestation.
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basics
With fruit trees , the focus is often on a rich harvest. So that this is not endangered, some hobby gardeners and self-cultivators resort to chemical methods as a preventative measure. In an age of climate change and environmental protection, the use of chemical agents is strongly discouraged. There are equally effective ways of prevention that are environmentally friendly and also never pose a health risk.
Prevent in time
Depending on the temperature, the cherry fruit fly (Rhagoletis cerasi) emerges from the soil between mid-May and the end of June. After about ten days, the females start laying eggs directly under the fruit skins. Depending on the method, it is important to wait for the right time in order to achieve promising results.
Prevent instead of fight
Once the larvae have developed in the cherries from the laid eggs, they eat their way through the pulp. They “dive” into the ground to pupate. Either they let themselves fall and get to the ground through falling fruit. There they hibernate and emerge the following spring as an adult fly. The new cycle begins with renewed oviposition. In the worst case, if you don’t prevent, you will have to deal with masses of worms every season, while prevention intelligently interrupts the cycle and prevents an infestation in the long term.
Preventive Methods
The following have proven to be effective methods of preventing worms:
bottom foil
A bottom foil should be used to prevent the worms from getting into the soil for further development. Alternatively, a fleece can also be used. The following should be noted:
- Lay out before harvest maturity is reached (around June)
- Dispose of previously fallen cherries quickly
- Fix foil/fleece with stones or similar
- collect fallen worms daily
- when all the cherries are gone, remove the foil/fleece
- ideally mulch afterwards
Harvest early
If worms have been spotted, early harvesting is an effective way to stop growth near the tree. Although the cherries do not become inedible due to the worms and can still be eaten after special treatment, harvesting unripe and not yet edible fruits reliably prevents a renewed and possibly more severe infestation in the following year.
Yellow boards and sticky traps
The cherry fruit flies can be prevented from laying their eggs with yellow boards and sticky traps. These methods are not particularly reliable, but at least they help to curb the uncontrolled spread and reproduction and prevent worms in cherries. That’s how it’s done:
- Hang yellow boards/sticky traps in the tree
- Attractants attract flies that stick to it
- Maintain a distance of around five meters between them (roughly corresponds to the effective radius)
- Replace boards/traps as soon as half the area is “occupied” (more holding area increases the number of flies caught)
- Use from mid-May
- additionally prevent with other methods (e.g. mulch and foil)
Apply a layer of mulch
In order to pupate, the larvae need a certain amount of soil warmth, which is what slowly develops in spring. To delay the time, it is worth laying a thick layer of mulch around the tree trunk. What you should know about this method:
- Mulch has an insulating effect and delays pupation
- due to later fly development, ideally already red fruits that are not used for laying eggs
- without a suitable place to lay eggs, flies take off
- Application in spring at the latest
nematodes
Nematodes are extremely small roundworms that penetrate the skin of the worms and enter the body. There they literally eat the parasites from the inside. They die and no more new egg-laying flies emerge from them. The following should be considered when using nematodes:
- Buy nematodes in powder form
- Put the powder in lukewarm water and let it dissolve well
- Pour evenly over a large area on the ground around the tree trunk
- Application only at a constant soil temperature of at least twelve degrees Celsius (otherwise nematodes are not active enough)
- do not apply at high temperatures or hot midday sun (otherwise the nematodes will dry up quickly)
- Efficiency: maximum 50 percent, therefore repeat application several times at intervals of one week
safety net
Typically, the use of a protective net is only seen in commercial cherry growing because the larger the tree, the more complicated the consideration. But it works reliably and keeps the flies from getting to the cherries.
If you are not afraid of the effort, you can proceed as follows and thus prevent worms in cherries:
- Use a net with a maximum mesh size of 0.8 x 0.8 millimeters
- complete attachment required
- pay attention to the lock on the trunk
- In the case of large/mighty cherry trees, it is also possible to re-net individual branches
- Application as soon as the first fruits ripen
Natural predators
Worms or larvae and cherry fruit flies are favorite foods for many animals. This can be taken advantage of by specifically attracting these animals or placing them in the immediate vicinity. The main natural predators include:
- Chickens (Gallus gallus domesticus) for pupae
- Ducks (Anatidae) for dolls
- Common Swift (Apus apus) for flies
- Swallows (Hirundinidae) for flies
- Ichneumon wasps (Ichneumonidae) for larvae
- Carabidae for larvae
- Spiders (Arachnida) for larvae
