What Causes Grape Berry Shrinking? A Detailed Guide to the Latest Control Measures

Grapes are a fruit we eat often in daily life. They taste sweet and tart and are highly nutritious, making them very popular with consumers. However, berry shrinking during grape growing is a troublesome problem: it seriously affects the normal growth of grapes, reduces both yield and quality, and brings economic losses to growers. So what causes grape berry shrinking? And how should it be controlled? Let us take a look together.

1. Symptoms

At first, small light brown spots form inside the flesh, then gradually expand. In severe cases, the skin turns black, and light brown, dark red, or dark gray patches appear on the affected areas, which become sunken. When the skin over the diseased area is peeled back, the flesh underneath looks as though it has been bruised, and after the fruit ripens, the flesh in the diseased patch is as firm as it was initially.

2. Causes

Berry shrinking disease generally occurs under high temperature conditions. The main causes are insufficient water, imbalance of hormones such as ethylene, and deficiency of trace elements such as boron and calcium. When soil moisture remains high for a long time, the opening and closing function of the leaf stomata becomes blunted. If the temperature then keeps rising, the leaves evaporate too much water and cannot draw enough water from the roots, so the leaves take water from the fruit, which triggers berry shrinking disease.

3. Control Measures

Carry out intertillage to improve soil aeration, keep aboveground and underground water balanced, and ensure root vitality throughout the entire growth period. Ditches in the orchard can be dug deep to drain water promptly and maintain the water balance between the aboveground and underground parts. Apply more organic fertilizer to thoroughly improve the physical properties of the soil, increase the soil organic matter content, and make the soil better in water permeability, water retention, and aeration; this also provides sufficient nutrients for plant growth and fruit development. At the same time, control the application of nitrogen fertilizer, which can cause excessive vegetative growth of branches and leaves in a year and compete with fruit growth for water and nutrients. Remove affected berries promptly to avoid useless nutrient consumption. Boron and calcium fertilizer can be applied as a foliar fertilizer; it is recommended to apply it once before flowering and to spray it 2-3 times continuously during the young fruit swelling stage, so as to increase nutrient supply, strengthen tree vigor, and improve disease resistance.

The above is an introduction to the causes of grape berry shrinking and its control measures. We hope it helps you. To learn more related knowledge, please stay tuned to us.