Recommendations to face the rain and prevent damage and fruit splitting

Recommendations to face the rain and prevent damage and fruit splitting

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recommendations to face the rain

A few days ago, we told you about the rains that are affecting Chile – the largest exporter of cherries in the world – in the middle of the harvest season, and how this has resulted in a decrease in boxes that will be sent abroad.

Well, Chile is not the only country affected. These weeks the rains also hit sectors of Australia, where the agricultural sector has been greatly affected. Specifically, areas of western Victoria and South Australia recorded more than 100 millimeters of rain in a matter of minutes, as reported by local outlets.

The early varieties that were about to be harvested, and with the intention of being exported, were the main ones affected by the climatic event, and although it is not yet a significant impact damage -as in the case of Chile- it does worry the farmers that these conditions can continue and complicate what seemed to be as good a season as has not been seen in years.

But how to confront a climate phenomenon that cannot be stopped?

Here are some recommendations…

The first thing, according to various experts, is to understand that more than the millimeters of water, the time the fruit is exposed to water is the main danger.

As for specific measures to take, there are several that can be considered to avoid damage and the much-feared cracks.

1. Protective hydrophobic products: These are protective hydrophobic serous films based on natural phospholipids or fatty acids that prevent water absorption, preventing fruit splitting.

Its application should be done at the beginning of color, considering that it should be done after the application of gibberellic acid.

For this technique it is essential that the fruit is completely covered, since the protection it obtains will depend on this. For this reason, it is recommended to make successive and homogeneous applications, therefore tests must be carried out in the target areas, pedicellar cavity and distal area, which is where the risk must be lowered, since prolonged exposure to water in these sectors ends in a split.

2. “Saturation” irrigation before the rains: It consists of watering before rainfall in order to reduce the sudden absorption of water by the roots; In this way, it is possible to avoid an abrupt increase in the volume of the fruits, avoiding splitting.

You should begin by carrying out short irrigations (2-3 hours), about 48 hours before the rain, in order to reach a state of saturation of the soil in the first 20-30 centimeters of depth. This technique should be repeated as many times as necessary in the event of possible precipitation.

However, it must be considered that if this is put into practice very close to the rain, 12 hours or less in advance, it is advisable to continue watering while there is precipitation. It is a very important strategy to prevent damage in orchards that have plastic covers.

3. Ca Chloride (CaCl2): It has been determined that foliar application of calcium could reinforce the structure of cell walls, providing greater mechanical resistance to tissues. Foliar applications of salts such as CaCl2 (and other salts such as K Chloride, Mg Chloride) allow balancing the osmotic pressure between the interior of the fruit and the environment, limiting the absorption of water by the fruits.

Constant and successive applications must be made before and during the rain episode, considering intervals of no more than 3 hours, in order to achieve the expected objective. Applications should be made in concentrations of 0.5% (500 g./100 L.) if the rain is less than 1 hour; If the period is longer, a concentration of 1% CaCl2 should be used, that is, 1 Kg of Ca Chloride / 100 L of water.

Constant and successive applications before and during rain at use concentrations of 0-5%-1% have been favorable when adequate operation has been maintained. The operation is complicated because it requires a high demand for the use of machinery since it should be applied with maximum intervals of two hours in the same place while it precipitates to avoid the washing effect of the precipitation.

4. Post rain water removal:  Removing water from the plants once the rain has ended, mainly from the pedicellar area of ​​the fruits, is essential; This task can be carried out with the use of helicopters or misting machines.

In the case of turbo foggers – which are originally used to carry out different applications in orchards – these must be without load, in order to generate wind flows that allow water to be removed. They should be used at full power, never completely empty, but with a little water so that the machines do not run dry.

The first round should be quick and a second should be evaluated to be able to throw away all the water from the plants; You can also carry out a round with two teams in parallel in adjacent rows, this causes the wind flows to overlap for better effectiveness and remove water from the foliage and fruit. Ideally, blowers should be used, since their way of applying air is much more efficient.

With the same idea of ​​generating wind, helicopters must fly over the plants; The route and height of the helicopter must be designed and established based on its wingspan and power. It is important that at the time of flight the orchard floor is with a certain humidity, to avoid raising dust that can be harmful to the fruit and the execution of the work.

The use of helicopters is expensive, but it has been shown to be effective in removing water from trees, preventing scores, especially those that are lodged in the pedicellar area. 

Additionally, frost control propellers can also be used as complementary methods, as they produce wind that allows the water on the fruit to drain.

Finally, it is of utmost importance to consider that, in the event of a rainfall event, the orchards have received the proper application of fungicides, always keeping in mind the tolerances, considering the little time left for the harvest.


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