But fear not, there are several weapons at our disposal to fight this intruder and save the precious harvest.
Prevention: a step forward against the enemy
- Watchful eyes on attackers : Monitoring the presence of flies with yellow chromotropic or pheromone traps is the first step to acting at the right time.
- Irresistible baits : Bottles with a mix of water, sugar and ammonia attract and capture flies, reducing their numbers.
- Natural barriers : Kaolin, a clay that creates a film on olives, prevents flies from laying eggs.
- Copper ally against diseases : Although mainly used against fungi, copper can also act as a deterrent for flies.
If an infestation is ongoing, it is necessary to intervene decisively, but always with respect for the environment and health.
- Targeted insecticides : pesticides authorized by the appropriate regulatory bodies (EU, Ministry of Health, and Regional governments) that control the development of juvenile and adult insect forms. They must be used with care, precision, and expertise to produce excellent oil, a positive result for the olive grower without harming the environment or the community.
Attention :
- The choice of method to use depends on the intensity of the infestation and the characteristics of the olive grove.
- Consult an expert for an appropriate and safe control plan.
- The adoption of sustainable agricultural practices, such as integrated pest management, can help reduce olive fruit fly pressure.
What are the best methods for eradicating the olive fruit fly, and what changes?
There is no single method capable of being decisive .
The best approach is the result of a combination of agronomic choices that intersect the various actions to keep the olive fly population under control and ensure good quality olive and oil production.
The use of chemical control methods alone, provided they are permitted by law, exposes, if abused or misused, to the risk of pesticide residues accumulating in the oil beyond legal limits. To prevent this from happening, it is essential to use pesticides correctly, adhering to the maximum number of applicable repetitions and the withdrawal period indicated on the label and in official documents.
However, not everyone plays the olive growing game by the rules. In fact, the use of pesticides that are no longer in use because they have been revoked is widespread.
The use of these products actually represents contamination and makes the product unmarketable.
The relationship between the farmer and the mill must be one of full trust and shared responsibility.
Biological defense: what are the natural allies against the olive fruit fly?
Nature offers effective alternative solutions to combat the olive fly, while respecting the environment and health.
Here are some biological control methods:
Natural antagonists :
- Psyttalia concolor : A parasitoid insect, a true natural enemy of the olive fruit fly, whose larvae feed on the parasite's eggs and pupae.
Biological traps :
- Irresistible Attractants: Bottles containing a mix of water, sugar, yeast, and ammonia attract and capture adult flies.
Cultivation methods :
- Timely harvest : Bring forward the olive harvest before the fly population reaches its peak, reducing the time available for infestation.
- Targeted pruning: Good pruning management promotes aeration and reduces humidity within the olive tree canopy, creating an environment less favorable to the development of the fly.
To effectively combat the olive fly, it is important to know how to recognize it:
- Size and color : Small adult (about 4-5 mm) with a light brown body and yellow head.
- Wings : Characteristic transparent wings with a dark spot at the tip.
- Behavior : Females lay eggs inside olives, preferring the larger and more fleshy ones.
- Damage : The larvae, feeding on the fruit pulp, cause rot and premature fall of the olives.
Strategic Defense: Exploiting the Olive Fly's Weaknesses
In addition to direct and biological control methods, the olive fruit fly can also be fought with cultural methods , exploiting its weaknesses and making the environment less favorable to its development.
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Early harvest: picking olives on the fly
A simple but effective method is to anticipate the olive harvest. This reduces the number of olives available to females for egg-laying, drastically reducing the fly population.
How to do:
- Monitor the fly population trend with chromotropic or pheromone traps.
- Harvest the olives when the infestation level is still low and the olives are starting to turn brown, but are not yet ripe.
- Use harvesting techniques that minimize damage to plants, such as hand-harvesting or netting.
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Pruning: air and light against flies
The olive fruit fly prefers humid, poorly ventilated environments. Careful pruning can therefore hinder its development.
How to do:
- Carry out regular and targeted pruning to improve the penetration of light and air into the tree canopy.
- Remove dead, diseased, or intertwined branches that promote the creation of humid microclimates.
- Open the center of the canopy to allow air to circulate.
- With these simple cultivation measures, it is possible to create an environment less favorable to the olive fly, reducing the need for invasive interventions and promoting the health of the olive groves.
When should you treat the olive fly?
Olive fly treatment is generally recommended during the summer, with particular attention to the months of July, August, September, and sometimes October, when the fly population is at its peak.
Is it possible to calculate the risk in advance?
Evaluating climatic conditions in the field through technological applications allows for a risk and severity assessment, helping the farmer or olive grove owner, along with the support of the agronomist, decide how best to intervene.
For this reason, Frantoio D'Orazio is considering purchasing an agrometeorological shelter capable of collecting and storing useful data to provide valid support for decision-making in the field.
