Since its presence in Chile was first detected in 2017, the spotted-wing fly or Drosophila suzukii has focused the attention of farmers and researchers in an attempt to stop the damage it causes in the national fruit sector. The experience gained by the INIA Quilamapu Entomology Laboratory in Chillán caught the interest of a researcher from the National Institute of Agricultural Technology, INTA, of Argentina, who stayed for almost a month in Ñuble to learn more about the behavior of this aggressive pest and to share her own experience with this insect in Mendoza.
Over the past six years, the presence of the fly Drosophila suzukii It has been a source of great concern among fruit producers in central and southern Chile, causing large economic losses in berry and cherry orchards, mainly affecting family farming.
"The intensity of the attack by this pest depends on the combination of climate, orchard management and fruit supply," said INIA Quilamapu researcher and entomologist Luis Devotto, who has been studying the behavior and control alternatives of this insect for seven years.
The specialist added that the fly becomes more dangerous in smaller orchards and in houses with fruit trees, either due to a lack of effective control tools for these segments or due to a lack of incentives to control it.
The agricultural engineer and doctor in agricultural sciences highlighted that this pest has a high reproductive potential, since the fruit that falls to the ground, either due to over-ripeness and/or lack of harvest, meets the ideal conditions for the insect to reproduce and give rise to "true clouds of new flies." He explained that a single kilo of blueberries that reaches the ground can give rise to 1,100 blueberry larvae. Drosophila suzukii, and in just two weeks they can be the parents of tens of thousands of new individuals that will restart the life cycle again and again.
Devotto clarified that this pest has arrived in Chile to stay and that it is necessary to learn to live with it, trying to limit the damage it causes, in order to continue with the process of marketing and exporting berries and cherries.
Visit of an Argentine researcher
It is at the Entomology Laboratory of INIA Quilamapu, where researcher Luis Devotto and his team carry out several lines of research and training concerning the spotted-wing fly. The information recorded - from several seasons - on the habits and behavior of this insect with fruit species, regions and types of production, are essential to increase the effectiveness of control strategies. This technical background was what the agronomist and researcher of the National Institute of Agricultural Technology (INTA) of Argentina, Carla Chiandussi, who works at the La Consulta Experimental Station in Mendoza, wanted to learn about.
For three weeks, Chiandussi joined the team to carry out field and laboratory activities. His interest focused on evaluating the damage caused by the fly to the quality of the fruit, as well as the residual effects of different insecticides used to cause the death of adult females and prevent the birth of new generations of Drosophila suzukii.
Regarding the experience gained, the Argentine researcher indicated that “the methodologies used in field trials provide a lot from a practical point of view and as a record for future recommendations to the producer.”
Although the spotted-wing fly was first recorded in Buenos Aires in 2014, Carla Chiandussi indicated that in the province of Mendoza the population of this insect and the damage caused are low so far. “It appears as another pest at the end of summer and beginning of autumn,” as shown by part of her work, which is reflected in the population curves of Drosophila suzukii.
Regarding the host fruit trees and the place where this insect multiplies, the professional mentioned that they are similar to those in our country, and that they are basically made up of cherry, strawberry and raspberry orchards, with 5 % of them affected.
The INTA researcher added that the knowledge acquired will also be useful for her doctoral thesis in Biology that she is doing at the National University of Cuyo, dedicated to the life cycle of Drosophila suzukii, its population structure and evaluation with organic insecticides.
Finally, Carla Chiandussi highlighted that her interest in learning about the work of INIA Quilamapu entomologist Luis Devotto was generated by the fact that he is a reference in the field in the southern cone of South America.
