What is the best time and technical points for grape panicle pulling (flower pulling)? What's the use?

In the process of grape planting, many growers find that when the grape ear is too tight, it is easy to lead to uneven color, fruit grains squeeze and deform each other, split fruit rotten fruit and other symptoms, affecting the appearance of the grape.

After fruit preservation treatment, some European and American grape varieties often have large fruit setting, troublesome fruit thinning in the later stage and high labor cost, so panicle pulling treatment before flowering is gradually applied in grape production. What is the best time and technical points for grape heading?

The function of panicle pulling

Reduce the work of thinning flowers and fruits in the later stage, and save labor.

The decrease of ear tightness is beneficial to the increase of fruit grain in the later stage.

Can enhance the effect of light intensity on flowers, you can "borrow light to sit fruit".

Increasing the gap between flowers and ears is beneficial to reduce the prevention and control of diseases and insect pests.

The use period of grape ear pulling

Period of use: the elongation of inflorescence is related to the period of use, the elongation of early inflorescence is not obvious, but the elongation of late inflorescence is not obvious. Generally, the new shoot is as long as 25~750px (6-7 leaf stage), and the inflorescence is 7-10 cm, that is, 20-25 days after sprouting and about 20 days before flowering.

Which grape varieties need panicle pulling?

Although the elongated inflorescence of grapes has many of these benefits, it is not suitable for all grape varieties. For example, after the ruby seedless ear, the ear is longer, but there will be large and small fruits and small stiff fruits, which are not easy to remove, but increase the labor of fruit thinning. So which grape varieties need panicle pulling?

Applicable variety

① big fruit type varieties: red Earth, Beauty finger, etc.

② tight panicle type varieties: Hongti, etc.

The varieties of ③ with high fruit setting rate and small inflorescence: Xia Hei, etc.

A variety not suitable for elongated inflorescences

The varieties with poor fruit setting of ①, such as Jufeng, etc., should not elongate the inflorescence.

The new shoot growth of ② varieties with better fruit setting is exuberant and the inflorescence should not be elongated, otherwise the fruit setting is not ideal and the ear is loose, which affects the commerciality.

In addition, when cultivated in hot and humid southern regions and facilities, inflorescences can generally elongate naturally, and there is no need to lengthen inflorescences deliberately.

Introduction of panicle pulling method

At present, the main methods of panicle pulling are fertilizer and water management and chemical heading.

Manage panicle pulling

Main features: relatively safe, but the speed is slow, the effect is not significant, and it is greatly affected by external conditions, especially temperature.

Specific methods: the time of fertilizing is usually about 15 days before flowering, and urea + water-soluble fertilizer containing biological stimulating hormone (humic acid, seaweed extract, amino acid, etc.) is applied, such as sea elf biological stimulant.

There are some problems: some practical experience is needed, and there is a certain risk in the use of pre-anthesis nitrogen fertilizer, and the method of panicle pulling varies with different regions, geography, temperature, light, humidity and tree potential. When using water and fertilizer, the average daily temperature is 20-25 ℃.

Chemical panicle pulling

Main features: quick effect, relatively safe, less affected by the environment.

Heading stage: the grape ear appears at the same time as the leaf, as long as the ear is removed from the leaf (5-6 leaves), it can be treated until 10 days before flowering. During this period, the earlier the drug is used, the more sensitive the grape is to the drug.

The commonly used agents are: gibberellin, Bibao, elicitor and so on, in which Qibao (gibberellin) is used more frequently, and the dosage is 1g 25~40kg with water.

Usage: inflorescence dipped or slightly sprayed inflorescence, it is better to dip inflorescence.

Existing problems: the use of gibberellin and adrenalin did not grasp the concentration, resulting in excessive pulling; ear pulling resulted in loose ear, not compact, deformed inflorescence, ear axis hardened, fruit easy to drop in the later stage, and so on.

Matters needing attention and management of panicle pulling

1. Rational use of medicament

Pay attention to the grape variety, tree potential, tree age, etc., at the same time pay attention to the weather, temperature, humidity, light and so on will affect, the concentration is as low as possible at high temperature, higher at low temperature, higher in tree strength, lower in tree strength.

Avoid the use of flower-pulling agents in strong sunlight; the concentration of treatment agents in different areas is different, so you should try to apply it on a large scale first!

two。 Prevent diseases

After the inflorescence elongation, the distance between the branches in the ear is enlarged. If gray mold, ear axis brown blight and other hazards, the ear will appear gap, affecting the quality of goods and sales. It can be prevented before flowering, and the medicament can choose pyrazole enylmorpholine, Pythium, isocarbamide and so on.

3. Do a good job of fruit protection

Fruit must be preserved when individual varieties are elongated. It is necessary to spray sea elves + boron fertilizer before flowering and flowering stage in order to increase the fruit setting rate.

4. Whole ear and fruit thinning

When the inflorescence is elongated, several spikelet peduncles on the shoulder are also elongated, and after fruit setting, several grains of the overlong spikelet peduncle are cut off to form a conical or cylindrical spikelet; the accessory spike is cut off before flowering; the spike tip should be pinched before flowering; after fruit setting, the fruit is thinned lightly and the small fruit is removed, thus reducing the amount of fruit thinning.