Five reasons for cucumber "yellow head"

The "yellow head" of cucumber refers to the yellowing of the stem near its growing point. Some of the top leaves are yellow and white in veins, and some appear yellow spots or plaques. The main reasons are the lack of zinc and iron deficiency, root injury, drug injury, hormonal poisoning, or diseases. Here, to remind farmers friends, clear the cause, symptomatic treatment.

First: lack of zinc and iron.

Zinc and iron are trace elements that are often neglected by vegetable farmers. Over time, when cucumbers excessively absorb zinc and iron in the soil and do not pay attention to supplements, zinc and iron deficiency in the soil are easily caused, and cucumbers are easy to “yellowhead”. The first is the yellowing of the parietal lobe, the veins are still green, yellowing and whitening of the posterior veins, and the necrosis of the leaf margins gradually becomes dry. In this regard, it is recommended to pay attention to the application of micro-fertilizers in vegetable-based basal fertilizers, such as ferrous sulphate about 2 kg/mu, and zinc sulfate 1-2 kg/mu. After the symptoms appear, spraying with zinc and iron-containing foliar fertilizers can relieve this symptom.

Second: Root injury.

Injury to the roots, light caused by the "yellow head", severe cucumber plants wilted to death. The main cause of root injury is high or low ground temperature, excessive water and fertilizer. For example, in winter, the absorption capacity of cucumber roots decreases, and the resistance is reduced. If you do not control the fertilizer, it is easy to injure the roots. "Leaf by root length", the ability to absorb nutrients after a root injury was significantly reduced, it is prone to "yellowhead." Therefore, it is advisable to reduce the amount of watering in winter, to use small water, to replenish nutrients to protect roots and vines (such as 667 series fertilization) or humic acid fertilizers or Apollo 963 chitin fertilizers. The cucumber roots return to normal growth as quickly as possible, thus prompting the leaves to turn green.

Third: The occurrence of phytotoxicity.

After the phytotoxicity occurred in cucumbers, it first appeared on the leaves, and the leaf margins were dry or yellow, and the leaves were chlorotic, deformed, with spots or spots. It is recommended that the pesticide should be dispensed strictly in accordance with the prescribed concentration when spraying. Try not to mix multiple pesticides, especially try not to mix with copper preparations or foliar fertilizers. After phytotoxicity occurs, cytokinin mixed nucleotide leaf fertilizer (such as Green Wind 95) can be sprayed in time for remission.

Fourth, excessive melons.

Causes hormonal intoxication, causing the top lobe to turn yellow and stiff. After hormonal intoxication, the top sheet is stiff and the leaf margin curls up and grows slowly or not long. For plants with hormonal intoxication, they can spray Yunda 120 or Yundaquanshu mixed nutrient leaf fertilizer to relieve their symptoms under the precondition of suspending pods.

Fifth, infectious diseases.

If serious brown spot disease occurs in recent years, the yellow point of the top leaves is evenly formed when it is seriously damaged, resulting in cucumber yellow head. This can be sprayed with thiophanate-methyl or carbendazim mixed Baitai or acetaminophen and other agents for prevention and treatment.

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