Drosophila suzukii is a major pest of fruit crops in Europe. Unlike classic fruit flies ( Drosophila melanogaster ) which attack rotting fruit, it targets healthy fruit, causing considerable economic losses for arboriculturists, winegrowers and market gardeners. Its strong reproductive capacity and resistance to climatic conditions allow it to quickly invade orchards and plantations. Faced with this threat, what measures should be taken? Discover the solutions developed by Agrobiotop to fight it effectively.
Description of Drosophila Suzukii
Drosophila suzukii is also called spotted wing drosophila or SWD. This insect is native to Asia. Its rapid expansion in North America and Europe makes it a feared adversary of fruit crops. After its appearance in Italy and Spain in 2009, it was spotted in France in 2010. Since then, its presence has spread widely, now affecting the entire territory as well as several other European countries such as Belgium and Germany.
Unlike other fruit fly species that prefer rotting fruit, Drosophila suzukii directly attacks healthy fruit. This characteristic makes it particularly problematic for growers, who experience considerable losses. Its appetite extends to a wide variety of hosts, including small fruits such as strawberries, raspberries and blackberries, as well as tree fruits such as cherries, plums and grapes.
Its very high reproductive capacity contributes to its destructive impact. A single female can lay several hundred eggs, leading to rapid population proliferation.
Morphology of Drosophila suzukii
Adults are 2–4 mm long and have a yellow-orange to brown body, with visible dark bands on the abdomen. Their distinctive red eyes make them easy to identify.
A marked sexual dimorphism differentiates males and females:
- Males have a conspicuous dark spot on each of their wings.
- Females are slightly larger and lack these spots, but are distinguished by a serrated ovipositor, allowing them to pierce the skin of fruits to lay their eggs.
The eggs are oval in shape, milky white in colour, and about 0.2 mm in diameter. They have two elongated filaments that facilitate gas exchange within the fruit.
The larvae, which are maggot-like, are translucent and legless. They go through three stages of development before transforming into pupae. The latter, reddish-brown, can be observed inside infested fruits or near the ground.
Life cycle of Drosophila suzukii
Drosophila suzukii is distinguished by its speed of reproduction and its high number of generations per year , which can range from 3 to 13 depending on climatic conditions.
Adults emerge from diapause in early spring, at which time fertilized females resume their egg-laying cycle. Each female can lay up to 380 eggs during her lifetime, depositing them directly under the skin of healthy fruit. Temperature plays a key role in the duration of larval development:
- Eggs hatch in 1 to 3 days.
- The larvae go through three instars in 3 to 13 days, feeding on the flesh of the fruit.
- Pupation lasts between 3 and 15 days and can occur in the fruit or near the ground.
Adults are highly mobile and can travel several kilometres in search of new food sources and oviposition sites. This rapid dispersal contributes to their expansion and complicates control strategies.
What crops are under attack?
Drosophila suzukii shows a clear preference for red fruits and fruits with thin skin . Among the most affected crops are:
- Red fruits : strawberries, raspberries, blackberries, blueberries.
- Fruit trees : cherry trees, peach trees, plum trees, fig trees, persimmon trees.
- Wine
Do you need a solution against Drosophila suzukii?
Damage caused by Drosophila suzukii
Drosophila suzukii targets fruits exclusively, without affecting roots, trunks, branches, buds, flowers or leaves. Its mode of attack is based on the ability of females to perforate the skin of still healthy fruits to lay their eggs. Once hatching is complete, the larvae begin to feed on the pulp, which quickly alters the quality of the harvest.
The first signs of infestation appear as a collapse of the epidermis, followed by a progressive deformation of the fruit. As the larvae dig galleries, the flesh oxidizes and decomposes, accelerating its rotting . These lesions weaken the structure of the fruit and open the way to secondary infections. Pathogenic fungi, such as botrytis , then find a favorable environment to develop, accompanied by bacteria and molds that accelerate the degradation of the harvest.
When the infestation reaches a critical threshold, the quality of the fruit becomes insufficient for marketing, leading to significant losses. The rapidity of the insect’s development cycle further aggravates the situation, as one generation can immediately precede another, making control more difficult to master.
What methods of protection and control against Drosophila suzukii?
Prevention
One of the major axes of the fight against Drosophila suzukii is based on prevention. Several measures can limit its development and proliferation:
- Installation of insect nets : these nets, with very tight mesh, prevent access to the plots, although they can also reduce air circulation and encourage the appearance of fungal diseases.
- Prompt removal of damaged fruit : Overripe or fallen fruit should be removed and destroyed to prevent it from providing shelter for the pest. Effective destruction involves crushing or burying infested fruit deep.
- Moisture management in plots : localized rather than generalized watering limits humidity, thus reducing the conditions favorable to the development of drosophila.
Methods of control
Trapping : installing specific traps with target fermented baits allows you to detect the presence of Drosophila suzukii and assess the extent of the infestation. We recommend using the DROSOTRAP trap (contact us for the method of using these traps and their bait).
AGROBIOTOP solutions to combat Drosophila suzukii
We have developed several solutions to effectively combat this pest:
In trapping
- Trap DROSOTRAP trap (Consult us for the method of using these traps and their bait).
Physical barrier biostimulant
Fungal protection
For the fight against fungal diseases following damage by Asian drosophila:
Do not hesitate to contact us for the implementation of AGROBIOTOP solutions against Drosophila suzukii.
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