The late growth period of peanut refers to the period from the beginning to the full harvest of the fruit to mature harvest, that is, the full fruit mature period lasts for about 45-55 days. During this time no new leaves were added and the lower and middle leaves began to fall off. The focus of field management is to prevent early defoliation, especially the upper leaves, maintain a larger green leaf area and maintain a longer functional period, thereby increasing the number of effective results, increasing the degree of solidification, and increasing yield.
The main causes of early defoliation in peanuts are as follows: defertilization is premature, and sandy lands are more severe; leaf spot disease, especially black spot and brown spot disease, rapidly spreads once they occur, often resulting in a large number of leaves falling within a few days. Premature and excessive spraying of plant growth regulators, especially Pyrazole and paclobutrazol, and regulators containing this ingredient as the main ingredient are more serious. The main measure for preventing early defoliation is preventing disease and supplementing fertilizers.
1. Strict prevention of leaf spot leaf spot disease mainly occurs in black spot and brown spot disease. Both diseases are mainly damaged leaves. The onset of peanuts begins with symptoms from the lower leaves and gradually spreads to the upper leaves. Brown spots develop in the early stages of the disease and gradually develop into round or irregular lesions. The spot of brown spot is larger, yellow halos surround the lesion, and the spot of black spot is smaller, the color is lighter than brown spot, and the edges are neat, there is no obvious halo. The weather is humid or long-term rainy, the lesions can be combined with each other into irregular large spots, the leaves scorch, seriously affecting photosynthesis. If it occurs on the petiole, stem or fruit pin, it will produce oval dark brown or brown spots, while the whole stem or fruit pin will turn black and die, causing the peanut production to drop significantly. From the peanut to the late growth stage, there are many kinds of leaf spot that damage the leaves caused by early defoliation. It is mainly brown spots and net spot disease that are harmful and hard to control. Can be sprayed at the early stage of the disease. The better agents are: 80% of mancozeb 800 times, 70% thiophanate-methyl 800-1000 times, agricultural anti-water 120 times 200 times, 50% colloidal sulfur 200 times, 1:2: 200 times more Bordeaux mixture. Spraying should pay attention to spray evenly, spray thoroughly, to prevent leakage of spray, spray once every 8-10 days, and even spray 3-4 times, can basically control the occurrence of the disease.
2. Foliar-spraying peanuts In the late growth stage, the ability of roots to absorb nutrients from soil and the ability of root nodules to fix nitrogen began to weaken, while the ability of leaves to absorb nutrients was increasing. Foliar spray fertilizer supplement has many advantages such as rapid absorption, rapid action, and high utilization rate. It is a good measure to prevent early decending caused by premature senescence. Earthy sand, thin soil, lack of base fertilizer, short plants, weak growth, yellow leaves with deferring phenomenon of peanut, 1% urea solution can be used for foliar spray. Miaowang Zhujian has a tendency to grow mad, but it is not necessary to spray urea. Peanut leaves have a strong phosphorus absorption capacity. During the middle and late stages of growth, spraying 2%-3% of superphosphate calcium leachate per acre (filtering for 14-16 hours) 60 kg, spraying once every 7-10 days. , spray 2-3 times, generally increase 7% -10%. Or use 100-150 grams of potassium dihydrogen phosphate per acre and 50 kg of water. After fully dissolved, spray it in the evening or on a cloudy afternoon. It is best to spray 3 times, 7 days apart, if within 8 hours after spraying. In case of rain, re-spray 1 time. Peanut is extremely sensitive to iron, and it is planted on alkaline soils. It is prone to iron deficiency and shows symptoms of yellow leaves and whitening. If iron fertilizer is sprayed in time, it can turn green after a few days. Can use 0.2% ferrous sulfate solution sprayed every 5-6 days, continuous spraying 2-3 times.
Jiangsu Hespax Security Co., Ltd , https://www.hespax.com