Capsicum has relatively low light intensity requirements, and it has certain advantages in off-season production in winter and has higher cultivation benefits. Navel rot is one of the common physiological diseases of pepper, and it is also an important production hidden danger faced by off-season cultivation of pepper.
Umbilicus rot first manifests on the tip of the pepper fruit. Green-brown or gray-brown water-soaked spots will appear in the early stage, and the spots will gradually expand to the base of the fruit and be distributed in a nearly oval shape. Sometimes, the outflow of cell fluid often causes germs to grow, and a mold layer appears in the lesion.
1. The cause of pepper umbilical rot
The root cause of navel rot is calcium deficiency. The main causes of calcium deficiency in peppers are as follows:
① Low soil available calcium content
Under the action of rainfall or irrigation, acidic and sandy soils will easily lead to the loss of calcium ions and cause calcium deficiency; soil particles in sticky soils have strong adsorption capacity, which will easily cause calcium ions to be difficult to be absorbed by the roots and become ineffective.
② Insufficient transpiration pull
The mass of calcium ions is relatively large, and the transpiration pull of pepper leaves is weakened in the environment of low temperature and weak light, and the ability to absorb calcium ions decreases accordingly. If the functional leaves are reduced due to diseases and other reasons during the production process, the ability to absorb calcium will also be weakened due to the reduced transpiration area.
③ Precipitation and ion antagonism
Only water-soluble calcium can be absorbed by pepper roots. If water-insoluble precipitates are formed due to chemical reactions (such as with carbonates, etc.), calcium ions will become invalid and cannot be absorbed. In addition, if the content of nitrogen, phosphorus, and potassium in the soil solution is too high, these ions will compete with calcium ions during the absorption process of the root system, that is, ion antagonism will occur, resulting in insufficient absorption of calcium by peppers.
④ Other reasons
The causes of calcium deficiency in peppers are: the high degree of soil salinization, which causes root absorption stress; the soil is dry, and the ability of calcium ions to move in the soil decreases; soil-borne diseases or application of insufficiently decomposed organic fertilizers cause poor root development.
2. Measures to deal with pepper umbilical rot
① Foliar calcium supplement
Foliar spraying is a quick way to supplement calcium fertilizer, but the spraying time should be earlier, and spraying when calcium deficiency symptoms appear will not help. The best time to spray is in the evening, when the air humidity is high. After spraying, the leaves remain moist for a long time, which can prolong the time for calcium absorption. It should be noted that this method can only be used as an auxiliary form of calcium supplementation for peppers .
② Calcium supplementation in the roots
When applying calcium fertilizer to the roots, care should be taken to avoid applying it together with water-soluble fertilizers such as nitrogen and potassium fertilizers, so as to avoid mutual antagonism and affect the absorption efficiency. Through strong transpiration, it can play its role as soon as possible.
③ Strengthen root management
A good root group is the premise of maintaining a good absorption of calcium for peppers. During field management, stepping on the border surface should be avoided, otherwise it will cause soil bonding and weaken the growth and absorption capacity of the root system; in terms of water supply, if the water content is too high High water will inhibit root respiration and reduce root absorption capacity, so water should be watered frequently to keep the soil within the appropriate water content range.
There are certain similarities between pepper sunburn and navel rot. Accurately distinguishing the differences between the two is the prerequisite for effective prevention and treatment of navel rot. The two main manifestations are:
① There are obvious depressions in the lesions of navel rot, but there is no sunburn in sunburn. ;
② Umbilical rot first appeared on the fruit tip, but sunburn was not limited to the fruit tip;
③ Umbilical rot spread in all directions of the whole plot in flakes, while sunburn concentrated on the sun-facing parts.
