One permanent challenge avocado growers face throughout North and South America is the pruning of their orchards. Pruning an avocado tree improves the amount of sunlight the leaves receive and, therefore, enhances its productive performance, while also preventing the orchards from becoming overcrowded.

As Mauricio Navarro, an expert in nutrition and fertigation of horticultural crops, explained during his presentation at the 8th Jalisco Avocado Congress, “Even though it seems that the topic is making strong progress, in reality, orchards are overcrowded from California to Chile, indicating a gap between theory and practice.”.

The expert stated that many courses, talks, and pruning models are available, but it is not being done correctly. The problem, he explained, is that there are several issues in tree productivity when this happens.

“I have been to orchards in Colombia, Peru, Mexico, Chile, and Ecuador, among others, and sometimes I arrive and I don't see a defined architectural model, so there is a big gap between what we trainers teach and what I find in real life,” Navarro said.

He asserted that, as long as producers cannot maintain trees for 50 years with their useful life at 100%, there is still a lot to continue learning.

Characteristics of the avocado tree

Due to its origins in humid forests, the avocado tree has monopodial growth, meaning it naturally tends to etiolate, that is, to compete for light.

This emphasizes the importance of respecting the spaces between each tree because if left to its own devices, the tree ends up climbing on top of the one next to it. “When this happens and it gets shaded, the orchard becomes unproductive and full of diseases and pests,” Navarro said.

In addition, the avocado tree generates production in new branches, meaning that it does not repeat production at the same point of growth between one season and another.

“That’s why pruning renews wood, and if done correctly, it stimulates new buds that will produce new avocados, which is the main reason for pruning,” he said.

He added that the tree does this process on its own, but on a smaller scale, since each cut made in pruning can generate between 4 to 5 new growth points, boosting the wood renewal process.

Pruning objective

Navarro explained the concept of strategic pruning, which is done tree by tree, identifying wood that has already yielded avocados and is becoming unproductive. This wood has no new shoots, so pruning must identify this wood and remove it to maximize the productive wood.

“A pruner must have sufficient agronomic judgment to answer the question: why did you remove that branch?” he said.

He explained that, unfortunately, in Mexico, those who prune often do not understand the logic behind the practice, and those who conduct pruning courses and understand tree behavior do not participate in the actual pruning.

“The big gap between what we know about pruning and what is pruning in the world is that what we know how to prune we can't,” he expounded.

He then emphasized the importance of training pruning crews to understand why they are removing or leaving branches on the tree.

He also emphasized that the most important aspect is to have an architectural model for each orchard, control the tree size, and maintain productivity.

Pruning also makes the use of water, fertilizers, and pest and disease control more efficient.

The expert pointed out to the attendees that if they leave their orchard without pruning, the orchard is finished.

Selective and strategic pruning

Navarro was against general pruning and in favor of strategic pruning.

“The key difference between general pruning and strategic pruning is the selectivity of branches to identify those that will produce avocados each season,” he said.

However, pruning needs to vary among different productive origins, so growers should understand the type of terrain, soil, and the number of hectares to prune to do what is right for their orchard, always consulting an expert.

The Global Avocado Summit organized by the Chilean Avocado Committee and Yentzen Group will be held on November 21 at the Casino Monticello event center.