As olive oil is one of the main products that the Spanish industry produces, it is not surprising the impact that the olive fly ( Bactrocera oleae ) has on its farmers. Every year large amounts of effort and money are invested in the fight against this pest, which is the main one in olive cultivation and mainly affects olives, spoiling them, but it can even end up affecting the entire olive tree in severe cases.
If you want to learn more about the olive fly and its treatment , join us in this article where you will find a guide on this pest.
What is the olive fly and its cycle
With the scientific name Bactrocera oleae , at first glance the olive fly does not differ much from those that are common to see in most urban environments. It is a pest that can be found throughout the Mediterranean area, as well as in much of Africa, the Canary Islands, India, Western Asia and California. the life cycle of the olive fly is as follows:
- Their life cycle begins with the laying of eggs by the females, which they carry out by piercing the skin of the olive with their oviscapto, a specialized organ. With it they deposit the eggs under the skin of the olive , when the olive has a diameter of around 8 mm. This sting leaves a visible mark on the olive, dark green at the beginning and brown later, when it heals.
- The egg hatches between 2 and 10 days after laying, depending on the weather and the season.
- The larva grows by digging galleries in the fruit, developing and making two molts. When it is near the third and last molt, the larva prepares its exit from the fruit.
- In the warm months, the larvae transform into a pupa inside the olive, next to its skin, until it takes its adult form and leaves the fruit.
- In cold months, on the other hand, the larva pierces the fruit to fall to the ground, where it forms the pupa, in which it remains until the arrival of the following spring or warm season.
The length of its biological cycle is highly dependent on the weather and the season, and can range from a minimum of 20 days when the temperature is optimal, to up to 5 months if the pupa overwinter in the ground, hibernating. Its ideal temperature is around 20ºC. Above 30 ºC the olive fly becomes less fertile, and above 32 ºC many of its eggs die. In the same way, below 0 ºC this insect cannot survive either. Thus, in coastal crops the fly develops during a good part of the year, while in indoor crops its months of activity are more focused on spring and autumn.
When to treat olive fly – treatment period
Since, as we have just seen, this pest evolves very differently depending on the climate and local conditions, no universal time can be established for its treatment. Instead, to know when to treat the olive fly it will be necessary to:
- Analyze how widespread the pest is.
- Where are you in your cycle?
- What is the best treatment to apply.
How to fight the olive fly – treatment
There are various treatments to eliminate the olive fly .
- When it is not very widespread, it is usual to partially use olive fly insecticide , using the patching and attractant technique, so as not to saturate the crop with chemicals.
- For a total treatment, if the affectation is very serious, the phytosanitary products for the olive fly will be applied only when the harvest affectation is more than 1% in the greening season, or 3% in the oil mill.
- It is also possible to resort to an ecological treatment for the olive fly , especially if we are looking for an ecological olive grove. In this case, the most popular and used measure is olive fly traps.. Of these, the most common is the so-called olipe trap. These can be made at home, recycling old plastic bottles, and although their economic cost is very low, their effectiveness is more than proven. It is manufactured using a PET bottle, in which a few holes of about 5 mm in diameter are drilled in its upper quarter. Then the lower half of the bottle, somewhat below the holes, is filled with attractant, diammonium phosphate dissolved at 3 or 5% being one of the most used. The trap is hung on the southern branches of the olive trees, covered from the direct sun, and the flies will enter through the holes to drown in the water. The trap owes its name to the Cooperativa Olivarera los Pedroches, where it was devised.
- Finally, biological control can also be used with the introduction of predatory species of this insect, especially in its soil phase during winter, as well as the use of entomopathogenic fungi in the soil of the crop.