When is the best time to apply the first round of medicine to peanuts?

The peanut is a crop suited to growing in warm, sandy soil areas, and the number of maturities varies from region to region, with cropping systems of one crop a year, three crops in two years, and two or three crops a year, so when should the first round of medicine be applied to peanuts when growing them?

1. When is the first round of medicine applied to peanuts?

The first round of medicine for peanuts is applied during the seedling stage to the early flowering stage; an appropriate amount of the agent can be mixed with water and sprayed evenly. Applying it at this time makes the peanut stems and leaves robust and improves disease resistance.

2. Peanut cultivation techniques

1. Temperature

Peanut seeds require a relatively high temperature to germinate; the optimum temperature is 12-15°C for the pearl-seed type and 15-18°C for the common type. Some varieties have strong dormancy and are difficult to germinate at low temperatures.

2. Fertilisation

Nitrogen should not be applied too heavily during the peanut seedling stage. Applying trace elements such as boron according to soil conditions gives notable results. Nitrogen, phosphorus, potassium and boron can all be applied as foliar top dressing. At a yield of about 250 kg per mu, every 100 kg of pods produced absorbs about 5-7 kg of nitrogen, 1-1.2 kg of phosphorus, and 2-3.5 kg of potassium, and the demand for calcium is second only to potassium.

3. Watering

Peanuts are relatively drought-tolerant, but their water requirement is large: about 225 kg of water is needed to produce 1 kg of dry matter. The period of greatest water demand and greatest impact is the flowering and podding stage, accounting for about 50% of the total water requirement; drought during this period affects flower bud differentiation, flowering, fertilisation and the elongation of the pegs. Dry soil also hinders the pegs from entering the soil. In the rainy southern regions, attention should be paid to drainage so as not to affect the normal development of the pods.

4. Pests and diseases

Common diseases include peanut rust, early leaf spot, brown spot and late leaf spot, which are fungal diseases that harm the leaves. When peanut rust is epidemic, its impact on yield is greater than that of leaf spot, and in the production areas south of the Yangtze River in China it is especially severe when there is more rain and field humidity is too high. Early and late leaf spot occur relatively late, and their effect on plant growth and development is chronic; because the peanut has already entered the maturity stage, their harm is easily overlooked.

In some concentrated production areas, peanut bacterial wilt and root-knot nematode disease are also very serious. Reasonable crop rotation is an effective control method. In China, peanut virus diseases mainly include witches' broom, mosaic disease and stunt disease. Witches' broom is more serious along the southeast coast; when it occurs, the pegs do not turn toward the ground but instead turn upward in a hook shape, commonly known as “peanut male”. Sowing spring peanuts earlier and delaying the sowing of autumn peanuts has a disease-avoiding effect. Mosaic disease and stunt disease are more common in the north. Others such as root rot, small sclerotium disease, shell rot, crown rot and leaf rot also occur. Comprehensive measures such as crop rotation, disease-resistant breeding, careful seed selection, strengthened management and attention to drainage are generally used for control.