Chile: Spotted wing Drosophila 'could become most important cherry industry pest'

The Cherry Express
Chile: Spotted wing Drosophila 'could become most important cherry industry pest'

A Chilean researcher believes the spotted wing Drosophila could soon become the most important pest in the country's cherry industry and has urged pest management strategies to be redesigned to ensure it is controlled.

The insect, also known as Drosophila Suzukii, was found for the first time Chile last year and is capable of attacking a wide range of fruits from the very early stage of its maturity.

Luis Devotto, a researcher at Chile’s Institute of Agricultural Research (INIA) in Quilamapu told Fresh Fruit Portal the pest could be the most damaging for cherry growers within "in a few years".

"In general, pests such as insects or mites that attack the cherry tree have a much lower comparative importance than pests that attack other fruit trees such as table grapes, apples, and blueberries, among others," he said.

This is because in general the insects and mites that can be found in the cherry tree do not threaten the survival of the plants or substantially reduce the number of kilos of fruit harvested, he said. In addition, strict quarantine measures in Chile mean there have not been any rejections from importing countries.

On Oct. 31, the Chilean Fruit Producers' Association (Fedefruta) warned that over the previous few days there had been conditions in some central-southern areas that was conducive to the reproduction of the pest.

In Chile, fruit growers tend to be more attentive to diseases, are since there are organisms capable of killing trees and significantly reducing production, but Devotto said the arrival of the spotted wing Drosophila could change that.

"The fly directly harms the fruit, since it lays its eggs in the fruit and larvae then destroy it by feeding. Even when the eggs don’t give rise to larvae, the mere fact of breaking the cherry skin to introduce them causes loss of commercial value," he said.

As the plague is relatively new, the researcher indicated that the country has not yet set itself the goal of eradicating it.

"At this stage, the Chilean health authority, SAG, has been concerned with monitoring its progress throughout the country. With this information, SAG, other public institutions (INIA, INDAP) and private institutions (ASOEX, FDF, BIOFUTURO), have been in charge of informing producers when the pest approaches their region," he added.

"As eliminating Drosophila Suzukii from the country is not an achievable goal, multiple actions have been taken to prepare cherry producers to cope with this pest in the medium term, reducing the current uncertainty and adapting the foreign experience to the Chilean reality."

This has involved visits of foreign specialists from countries including the U.S., Netherlands, and Mexico, along with numerous seminars, technical talks, written recommendations, field days and training for growers.

In addition, INIA specialists have been collecting natural predators that attack other fruit flies to see if they can also attack the Drosophila Suzukii. There are also projects aimed at creating an insecticide based on a native Chilean fungus that can be used against this fly.

Devotto also spoke about the main precautions that growers must take to avoid the development of the fly, among which is not to have vegetation that produces fruit that can be used by the pest, such as blackberries.

"This can include removing the plants, removing only their flowers or applying insecticides when the fruits are present; training the harvesters and in general the personnel that enter and leave the fields so that they do not enter contaminated fruit and caring about the handling of waste (remains of fruit) in harvesting trays, bins, snacks, garbage, etc.," he said.

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