When is the best time to apply growth regulators to peanuts, and how should they be applied for good results?

Right now is the peak growth period for peanuts, and with the arrival of rain, peanuts can easily grow faster due to high temperatures, leading to excessive vegetative growth of stems and leaves and reduced yield. For this reason, it is necessary to promptly control excessive peanut growth. So when is the best time to apply peanut growth regulators? How should they be applied?

1. Why do peanuts need growth regulation?

It has become a widely recognized fact that when peanut vines grow excessively, they do not set pods. When peanuts have sufficient water and fertilizer, high temperatures and good light, their growth rate speeds up, making excessive vegetative growth of stems and leaves very likely. This excessive growth has no directly beneficial effect on increasing peanut yield and instead wastes soil fertility. If it is not controlled in time, the plant height becomes too tall, making it prone to lodging, and too much nutrition is supplied to the stems and leaves, reducing the nutrition needed for pod development. The pods are then not plump, which affects yield. At the same time, it can also cause premature aging when peanuts form their final pods in the later stage, further affecting peanut yield and quality. Therefore, attention must be paid to effectively controlling excessive peanut growth, promoting the transfer of nutrients to the roots, making the pods large and full, increasing the pod-setting rate, and thereby promoting increased peanut yield.

2. When should growth be regulated?

1) Best period: when a large number of pegs are entering the soil. At this time, the first batch of pods that have entered the soil are as thick as a little fingertip, and the tips of the second batch of pegs look like chicken beaks.

2) When water and fertilizer are sufficient and growth is vigorous, with plant height reaching 30-35 cm.

3) Before and after spraying, care should be taken to keep the field soil moist. If it is too dry, nutrient absorption will be unfavorable, and the inhibitory effect on peanuts will be increased, causing single-kernel pods.

3. Selection of growth regulators

In production, the more commonly used chemical regulator is paclobutrazol. First, if the dosage of paclobutrazol is too large, it will seriously affect peanut pod development, making the pod shape smaller and the shell thicker. If used for seed, emergence will be delayed and growth vigor weak. Second, if applied too early, it will worsen leaf diseases in peanuts, causing leaves to wither and drop early and leading to premature aging of the plants. Third, paclobutrazol has a long residual effect in the soil and can show an inhibitory effect on the growth of subsequent crops, so it is not suitable for continuous cropping. Therefore, it is recommended not to use it if possible, and its use is prohibited in peanut seed production fields.

4. Why does regulating growth too early reduce yield?

The timing of growth regulation is a key issue; doing it too early will reduce yield. For example, the full flowering stage is a period when vegetative growth and reproductive growth advance together. Using it at this time not only inhibits stem and leaf growth but also inhibits flowering, resulting in fewer pegs forming. If sprayed during the peg-formation stage, it inhibits peg elongation, making the pegs short and the pods thin, affecting the number of full pods and kernel weight.

5. How should growth be regulated in years with heavy rain?

Generally, use the normal amount. Too large a dosage affects pod development, making the pod shape smaller and the shell thicker, causing early leaf aging and withering, and there is also a trend toward worsening leaf diseases. However, in special years such as years with heavy rain, after the first growth regulation, if plant height exceeds 40 cm about 10-15 days later, it can be sprayed once more. At the same time, spraying should be uniform, avoiding repeated spraying, missed spraying, and rain immediately after spraying. High-yield fields can combine pest and disease control with a multiple-application, low-dosage method of chemical regulation, and care should be taken to appropriately reduce the amount of chemical regulator used each time.

When using it, grasp the following principles:

1. Multiple applications with a small amount. This means peanut growth regulation should be carried out in 2-3 applications to avoid using too much at once and regulating growth too early, which would affect normal peanut growth. The total amount of pesticide per mu should not exceed 40 grams (about 20 grams per application), and each spraying should not exceed 2 sprayer tanks.

2. Spray in the afternoon, and if it rains within 6 hours, respray.

3. Add a small amount of neutral washing powder when spraying to increase the spreading of the spray liquid and the absorption capacity of the leaves.

4. When spraying, spray the growing point at the top of the peanut, passing over it once, and do not spray repeatedly.

6. Integrated management techniques for peanut growth regulation

1. The peanut growth regulation stage generally has high temperature and high humidity, and it is also a stage when diseases such as peanut brown spot, black spot, and scab are likely to occur. It can be combined with growth regulation by adding a highly effective broad-spectrum fungicide to control leaf diseases;

2. At this time, peanut leaves, pegs, and pods can all absorb nutrients. The pod development period is a key period requiring nutrients, and at the same time nutrient deficiencies can easily cause yellowing and similar phenomena, so attention should be paid to supplementing foliar nutrients at this time.

3. Field growth conditions should be closely monitored, management should be strengthened, and the occurrence of leaf spot disease and premature leaf aging should be prevented.

4. Harvest in time and avoid harvesting too late, which worsens rotten pods and affects yield.

7. Several points to note

1. After chemical regulation, peanut fields should be closely monitored for field growth conditions, management should be strengthened, and the occurrence of leaf spot disease and premature leaf aging should be prevented.

2. Harvest in time and avoid harvesting too late, which worsens rotten pods and affects yield.

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