1) Covers: Without a doubt, this is the most effective method. There is no method or management that ensures the protection provided by rain covers. Their indiscriminate use, without the proper handling and materials, could influence the quality and condition of the fruit, but with handling in accordance with the proposed objectives, it can not only prevent rain damage, but could also improve characteristics such as size and even, with new technologies in the use of plastics, advance phenological states.
2) Uncharged turbo-nebulizers: Originally they are used to make applications in orchards, but in this case they are used to generate wind flows that allow removing water; they must be at full power, never empty, but with a little water so that the pumps do not work dry. The first pass must be fast, however a second pass may be necessary to be able to remove all the water from the plants. It is also effective to make a parallel pass with two units in adjacent rows, this makes the wind flows overlap and have greater effectiveness in removing water from the foliage and fruit.
3) Waxes and polymers: carry out successive and well-controlled applications to achieve the objective; the important thing is that the products are applied to the fruit in a homogeneous manner, therefore tests must be carried out in the target areas, pedicellar cavity and stylar zone, which is where we must reduce the risk, since we know that prolonged exposure to water in these areas ends in a crack.
4) Use of hydrophobic films (Biofilms): With products formulated especially for this work, research in Chile has shown good performance against rains that are not very intense or of long duration.
5) Use of Ca Chloride (CaCl2): Before and during rain, this strategy allows rainwater to remain off the fruit for as long as possible due to the effect of osmotic balance.
6) Drying: Ideally, with helicopters and blowers, efficiently and just after the rain has finished. Frost control propellers can also be activated, which generate wind flows that allow the water on the fruit to drain off and ultimately cause damage.
In the case of helicopters, their route and height must be defined based on the size and power of the helicopter. It is important that when the helicopter is flying, the ground has a level of humidity that prevents dust from rising, since this could be harmful to the plants and complicate the visualization of the work.
The height of the overflight must be calculated empirically by trial and error with the aim of efficiently delivering the water with the least possible impact on the plants to avoid mechanical damage such as bruises or punctures.
