Pilar Bañados, an academic from the Department of Fruit and Oenology at the Pontificia Universidad Católica de Chile, PUC, in conversation with Blue Magazine, is emphatic in arguing that blueberry crops in the northern part of Chile, which is where the most common fruit is produced early, they should be protected under plastic mesh or tunnels. The professional assures that it is not only a useful tool "that is being empowered and demanded by the markets in order to ensure compliance with supply and the development of programs", but is also key when it comes to being able to protect and better manage the crop, either to advance or delay harvests, or to protect it from extreme weather events. "The discussion is not whether it works or not, the decision is how I adapt this technology to my particular and specific situation," says Bañados.

Pilar Bañados is a specialist in berry physiology and production, with long experience in teaching, research and extension in physiology of fruit plants. His research area includes the physiology of berry and fruit plants with an emphasis on lethargy, floral differentiation and nutrition.

Costs and Benefits

The cost of implementing a macro-tunnel, with plastic cover, that efficiently protects crops, ranges between USD3 / m2 and USD10 / m2 and the main benefit of using these polyethylene covers in blueberries - assures the academic - passes for the protection of the resources invested, and adds that although the investment is important, it should be considered a lesser evil when compared to what is lost if a frost or hail leaves the producer without fruit.

"I think you have to look at it as part of the investment, always looking at profitability," he emphasizes.

To this main objective must be added the possibilities it provides in the control of temperature, luminosity, relative humidity and wind.

You have to consider, says the expert, its qualities of transmission and diffusion of sunlight and thermal properties or ability to retain heat, because different materials provide different responses, depending on the needs of plants.

"You can also advance the harvest of the fruit, due to the effect of a higher thermal sum and it helps control extreme temperatures, causing damage to crops," he says.

For blueberries, we recommend using plastics with high light transmission, between 80% and 90%, and variable diffusion depending on the objective, between 40% and 70%.

According to studies, indoor cultivation improves the efficiency of photosynthesis, due to the increase in light scattering, as there is more diffuse light on the lower leaves and less excess light on the upper leaves.

Another of the qualities that stands out is the “umbrella” effect that macro-tunnels have, by preventing rain from falling on the fruit, reducing rotting, breaking of fruit and also allowing harvesting with rain. Depending on the plastic used, the harvest time can be prolonged or delayed and they are clearly an undeniable protection against wind, hail and frost.