When to Prune Avocados in Chile May 2015
The avocado´s natural growth habit causes it to generate lush foliage. Unrestrained, it can reach a great height and density. By controlling excessive vegetation in avocado trees it will be possible to increase the chance of getting higher yields and quality while reducing the incidence of alternate and irregular bearing. An unpruned tree produces many small fruit. When pruning, the fruit will be better distributed within the tree, allowing more light and nutrients to get to the fruit and improve their development. Furthermore, the wood parts will also assist in improving fruit size. Now, the question to be answered is when is the optimal time to prune in avocados in Chile. This was studied by Francisco Gardiazábal, agronomist, avocado expert and advisor at GAMA Consultants.
Gardiazábal and his research team developed a series of tests to determine the best time for pruning Chile avocados, which consisted of testing different times, every 15 days, in a range that extended from August to January. The idea of this initiative was to determine how the date of pruning influenced the new shoots, which are born in the month following, and these buds bloom the following year.
According to the expert, it was determined that all pruning undertaken from August to mid-October had excellent results. “Buds return the next year with a very good bloom, resulting in good fruit,” says Gardiazábal.
The situation was different for pruning carried out from October 15 onwards. “From mid-October until December, flowering decreased the longer we waited. In fact, trees pruned in January did not bloom at all.”
For this reason, it is recommended to prune as soon as possible after harvesting the fruit, and no later than mid-October.
Note that these dates may not be the best in areas of piedmont or flat lands, where the possibility of frost is higher. “When you prune in autumn or winter, you make trees more susceptible to frost. Therefore, it´s recommended to wait longer in these sectors- during late winter or early spring, between September and October (for those not familiar with Chile farming), before it starts flowering or has just started, so it will avoid any winter frosts that might occur” says Gardiazábal.
High density orchards
It´s important to highlight that hill-side orchards in a higher density, with narrow frames of 2.5 x 2.5 meters or 3 x 3 meters do not need to be any taller than 2 meters. The goal of the high density is not only the earliness, but also to increase the efficiency of workers tasks, for which it will it becomes essential to have smaller trees. “You want comfortable, easy crop that can be harvested by both men and women. At the same time, in orchards of short trees, the amount harvested is much higher than that obtained in an orchard of tall trees. Therefore, savings occurs at field level and growers earn more money” says Francisco Gardiazábal.
It’s critical not to exceed two meters in height, and producers can understand their growth and how sprouting develops. And that all budding from January onwards will be unproductive; well, actually counterproductive, because it will result in widening of the trees. Therefore, it is recommended at the arrival of autumn and early winter, to cut off of all the branches without fruit, in order to maintain the shape and height.
Due to the density of foliage of the avocado, it is strictly necessary to trim and prune, especially in the lower parts where there is almost no production due to the lack of light. In order to control this, the expert recommends open lanes, allowing the entry of light and enabling the bottom remain productive.To do that, it´s necessary to remove all the branches that produce greater shadow, that is, those side or central branches. “Often the central branches may be leaning on each other, so you should remove the side, so that the light filtration will increase. In other cases, there are one or more vigorous branches that are born in the center of the tree. In such cases, perhaps, it’s better to take out the central branches, ie those branches which disturb or remove light at the bottom and can be removed. That is the criterion to keep production in the inside and keep the tree in the desired size” he explains.
The use of light is essential, especially in varieties such as Hass, which have rapid growth and are easily shaded.
Banding technique
Another alternative is to use the banding technique, which involves cutting a ring of the bark, in order to briefly interrupt the flow of sap. The idea is to get the sugars and other organic compounds produced during photosynthesis to accumulate over the incision. Thus, having a greater amount of available sugars and organic compounds greatly increases flowering.
This technique has been traditionally used in avocado cultivation, but according to Gardiazábal, should not be used because it´s quite a controversial practice due to wear it causes on the trees. The problem with the banding technique is that while it boosts the production of flowers and fruit, the quality of the fruit will be diminished.
For this reason, it is recommended to use a bio growth regulator like uniconazole, which in addition to achieving increased production of flowers and fruits, generates a better caliber of fruit. “Sumagic (trade name) is so far is the only product registered for this component and is normally used. Its use does not create major problems”.
May 2014 article discussing the best practices for maintaining avocado trees in Chile.
Chile Property 