Peanuts in the late growth stage: do not relax field management

1. Preventing premature aging. For peanuts, the period from pod setting to full pod stage is when they need more water and fertilizer. If water and fertilizer are insufficient, it will cause poor plant development, weak growth, yellow leaves, and premature aging, resulting in a reduction in the peanut's green leaf area, decreased photosynthetic capacity, less nutrients produced, reduced dry matter accumulation, slower transport to the pods, and affected yield. For fields with premature aging caused by fertilizer deficiency, during the pod-setting to full-pod stage, spray 0.3%—0.4% monopotassium phosphate plus 1% urea solution at 50 kg per 667 sq m as a foliar application. The best time to spray is after 4 p.m. on a sunny day, once every 10 days, generally 2—3 times, which can effectively supplement nutrients and prevent premature aging. For fields with premature aging caused by drought, irrigation should be supplemented in time to meet the peanut's water needs, promote the absorption and transport of nutrients, increase dry matter accumulation, and increase yield.

2. Preventing excessive vegetative growth. During the full pod stage of peanuts, vegetative growth gradually declines, large amounts of nutrients are transferred to the pods, and dry matter accumulates rapidly. However, due to various factors such as temperature, rainy weather, light, and excessive application of nitrogen fertilizer, peanut stems and leaves grow excessively, close the rows too early, and the field becomes dense, consuming large amounts of nutrients, inhibiting the accumulation of dry matter in the fruit, and affecting yield. Therefore, for peanuts showing a trend of excessive growth, measures should be taken to inhibit vegetative growth and promote reproductive growth, which has a clear effect on increasing peanut yield.

3. Preventing waterlogging. Peanuts have the characteristics of “liking rainy weather, not liking waterlogged land” and “when the soil is dry, pegs do not enter the soil; when the soil is wet, pods do not plump”. Especially in the late growth stage of peanuts, peanut fields must never accumulate water. If there is rain or continuous rainy weather, drainage should be carried out in time to prevent waterlogging, which makes field humidity too high, causes excessive growth of stems and leaves, poor soil aeration, affects the root system and pod plumping, and easily causes large amounts of rotten fruit or sprouting, reducing yield and quality. When planting peanuts in plots with a high groundwater table, high-ridge cultivation must be implemented or drainage ditches dug well to lower the water table.

4. Preventing diseases and pests. The main disease in the late stage of peanuts is leaf spot. The chlorophyll in affected leaves is destroyed, photosynthesis decreases, causing early defoliation, affecting dry matter accumulation and pod maturity, generally reducing yield by 15%—20%, and in severe cases by more than 40%. For control, 1—2 sprays of 1:1:300 Bordeaux mixture should be applied before disease onset for prevention. In the early stage of disease onset, 50% carbendazim wettable powder at 800 times dilution can be used for control. The main pests in the late stage of peanuts are soil-dwelling pests, mainly white grubs, which should be controlled in time. When aphids occur in the late stage, when the rate of infested plants reaches more than 5%, 10% imidacloprid wettable powder can be sprayed for control.