Causes of Alternate Bearing in Pear Trees and the Latest Control Methods

Pear trees are grown in all parts of China, and pears are also very popular with many people. For pear growers, however, the alternate bearing phenomenon in pear trees is a major headache. Alternate bearing in pear trees can seriously affect pear yields and reduce growers' economic returns. So what causes alternate bearing in pear trees? And how should it be controlled? Below, the editor brings you the causes of alternate bearing in pear trees and control methods. Let's take a look!

I. Causes

1. Tree-related causes

In years when pear trees bear relatively many fruits, nutrients are continuously transported to the fruits. This causes a large reduction in the nutrient reserves accumulated in the pear tree body, so the tree does not have sufficient nutrients that year to form flower buds. Therefore, after passing through an "on" year, an "off" year occurs because too few nutrients were accumulated in the tree body. Then in an "off" year, because the fruit load is small, more nutrients are accumulated, and there are sufficient nutrients to promote flower bud differentiation. Thus the second year becomes an "on" year for the pear tree, and this cycle repeats, resulting in alternate bearing.

2. Environmental causes

The environment is one of the main causes of alternate bearing in pear trees. Under harsh environmental conditions, such as low temperatures, frost, and drought, pear tree growth is severely disadvantaged. For example, a pear tree that would normally bear fruit may suffer freezing damage to flowers or young fruit due to a late frost, leading to flower and fruit drop. This causes excessive nutrient accumulation in the tree body and the appearance of large numbers of flower buds, so the next year becomes an "on" year. In addition, pests and diseases can also easily lead to alternate bearing; pests and diseases readily cause defoliation and flower drop in pear trees. They affect flower bud differentiation in pear trees, and if not controlled in time, the next year can easily become an "off" year.

II. Control Methods

1. Reasonable pruning

We should control the number of flowers on pear trees through reasonable pruning and ensure a suitable leaf-to-fruit ratio for the pear tree. This avoids an imbalance between nutrient accumulation and consumption in the tree body and alleviates the alternate bearing phenomenon. In an "on" year, heavy pruning should be carried out, while in an "off" year, light pruning should be done. When pruning in an "on" year, we should, on the premise of ensuring that year's yield, control the number of flower buds and do more heading back of medium and long fruit-bearing branches. Deal with overly dense and overly long branches and improve the light environment. In an "off" year, fewer thinning cuts and fewer heading cuts should be made, and no major adjustment or renewal of the pear tree should be carried out. Then attention should be paid to summer pruning to promote the development of secondary shoots in an "off" year and increase the number of flower buds the following year.

2. Strengthen management

During the flowering and fruiting period of pear trees, we should appropriately thin flowers and fruits to avoid excessive crop load on the pear tree, adjust the leaf-to-fruit ratio well, and improve nutrient accumulation. Special attention should be paid to flower thinning; appropriate early flower thinning can effectively reduce nutrient consumption. Then attention should also be paid to fertilizer and water management to enhance the absorptive capacity of the pear tree roots and ensure nutrient uptake by the pear tree. Doing a good job in pest and disease control and avoiding natural disasters can also effectively prevent alternate bearing in pear trees. Finally, growth regulators should be applied reasonably to promote flower bud differentiation. In an "on" year, regulators such as ethephon are mainly used, while in an "off" year, gibberellin and the like are mainly used.

The above is a brief introduction to the causes of alternate bearing in pear trees and control methods. That is all for today's introduction. This article is for reference only, and we hope it can help everyone!