What are the latest causes of grape berry cracking?
Grape berry cracking mainly occurs during the berry ripening stage. It is a physiological disorder in grapes, manifesting as cracked skin. The exposed flesh reduces the commercial value, and after cracking, the juice leaks out and moisture is lost, which easily leads to dried berries or attack by pests and diseases, increasing losses. So what causes grape berry cracking? Do you know? Below, the editor brings you the major causes of grape berry cracking. Let's take a look.
1. Variety
Grape varieties are diverse. Different varieties have different flesh firmness and skin thickness, so their ability to resist compression and cracking also varies greatly. For example, varieties such as Red Globe have crisp and firm flesh, evenly and tightly packed berries, and relatively good skin toughness, so they resist compression strongly and are not prone to cracking; while varieties such as Kyoho and Ruby have soft flesh, uneven and loosely arranged berries, and a loose connection between flesh and skin, making them prone to cracking.
2. Improper water regulation
In the late growth stage of grapes, if the berry expansion period encounters drought, and then the ripening period encounters rainy weather or improper watering, the plant will absorb a large amount of water and transport it to the berries, accelerating the cell activity and division of the flesh, while the cell activity of the skin is slower. This strong contrast causes a sudden increase in berry turgor pressure, resulting in cracking.
3. Improper fertilization
Grapes need different nutrients during growth. If fertilization is too one-sided or improper, it leads to unbalanced soil nutrients, seriously affecting grape growth and weakening the fertilizer and water regulation capacity of the planting, making the berries highly prone to cracking during expansion. Specifically, this manifests as blindly applying large amounts of nitrogen, phosphorus, and potassium fertilizers while neglecting trace elements such as calcium, boron, and zinc, leading to nutrient imbalance in the soil and affecting growth; also, some growers apply excessive nitrogen fertilizer, causing cracking during the berry expansion period.
4. Improper pruning
During planting, in order to promote more branching and increase the number of flowers and fruits, excessive pruning of branches and leaves weakens the plant's nutrient synthesis and water condition capacity, causing cracking. Generally speaking, when pruning, 1-2 leaves can be retained on the secondary shoots above the fruit cluster. And each normally growing fruiting branch should retain more than 25 leaves.
5. Pests and diseases
Pest and disease damage is also one of the main causes of grape berry cracking. For example, pests include thrips and green plant bugs, and diseases include powdery mildew and gray mold, all of which can cause grape berry cracking.
6. Improper use of pesticides
In the process of grape cultivation, whether for pest and disease control or growth regulation, pesticides are used. These pesticides will more or less stimulate the grapes, injuring the berry surface and making them highly prone to cracking in the late growth stage.
The above is the full content on the causes of grape berry cracking. We hope it can help you. If you want to learn more about grape cultivation knowledge, please stay tuned to us.