Causes of Uneven Grape Berry Size and the Latest Control Methods

Grapes taste sweet and tart, and are a fruit that many people like. However, when growing grapes, uneven berry size often occurs, and uneven grape berry size is a common situation in every grape-growing region of China. After fruit set, grapes often develop berries of inconsistent sizes, some large and some small. There are many causes of this situation, and treatment must be tailored to the condition of the grapes and the orchard.

1. Variety-related causes

The cause of uneven grape berry size may be that a variety naturally prone to producing uneven berries was chosen. For example, Victoria: because of its own genes, it is naturally prone to poor pollination and fertilization, and poor pollination naturally leads to uneven grape berry size; the small berries generally have no seeds or very few seeds. In this case, such a variety can be avoided when choosing varieties, or the variety can be given a seedless treatment, and after all berries have no seeds, gibberellin expansion treatment can be carried out, and then the berries will no longer show this situation.

2. Boron and zinc deficiency

If grapes lack boron during growth, pollen will find it difficult to pollinate, the ovules cannot be fertilized, seeds cannot form in some berries, and fruit set will decrease accordingly. If zinc is lacking, the auxin in the grape plant will be insufficient, fruit set will decrease, the flower caps will be difficult to shed, and uneven berry size will occur. If boron or zinc deficiency occurs in the orchard, supplemental application should be carried out immediately according to the specific situation, and boron-zinc fertilizer should be added.

3. Adverse weather

If continuous high temperatures or rainy weather occur during the grape flowering period, pollination will become difficult, fertilization will be poor, fruit set will be difficult, and uneven berry size will form. If clusters shaped like an “H” are found in the orchard, then the uneven berry size is most likely caused by weather. Many friends in the north, fearing poor grape yield, do not water the grapes before flowering, but if high temperatures occur, this will cause the grapes to drop flowers and fruit. When low temperatures and abundant rain occur, a film should be placed over the grapes, lighting equipment should be installed inside the film, sufficient temperature and light should be given to the grapes, and drainage should be carried out in time. If continuous high temperature and drought occur, sufficient water should be irrigated to the grapes during the flowering period. Ensure the water requirement.

4. Hormone problems

Grapes require the use of hormones at several stages of growth, and improper hormone use at these stages will lead to poor grape development. For example, in the first period, gibberellic acid needs to be applied when elongating the inflorescence, but if it is not applied in time, pollination will be affected and the berries will generally be on the small side. The second is the flowering period; during flowering, many friends use fruit-setting agents to promote fruit set, but improper use will lead to poor pollination and the berries cannot expand normally. The third is at flower drop, when growers use expansion agents too early, the seeds abort, and the berries cannot expand. All kinds of hormones must be used reasonably at each stage; if you do not know how to use hormones correctly, you should use less or not use them.

These four are the most common causes of uneven grape berry size. Of course, there are many other causes, such as vigor, density, and so on, which the editor has not listed all of. Among them, the most important things to pay attention to are the use of boron-zinc fertilizer and hormones; whether deficient or excessive, they will seriously affect the normal growth and development of grapes, so their use must be given attention!