Causes and control methods of yellowing and blackening of orchid leaves

Orchid diseases occur all year round, especially in summer when humidity is high and temperature is high. It is the long season for orchids to grow, and it is also the season of high incidence of orchid diseases and insect pests. At the same time, it is the most distressing season for our orchid lovers. If we don't pay attention to it or deal with it in time, it will cause orchids to die. Therefore, the management and maintenance of orchids in summer is also particularly critical in one year. Today, I will analyze the causes and prevention methods of common diseases of orchids together with you for your reference!

1. Leaf tip yellow and black

Orchid leaves from the tip began to yellow, black, and gradually develop downward, this generally belongs to physiological diseases, is due to poor external environmental conditions or improper cultivation methods or hair seedlings nutrition can not keep up with the disease, non-infectious, do not worry too much, once found this situation should be placed in a cool and ventilated place to avoid sun exposure or direct, such as inconvenient to move should be shaded and cooling treatment, commonly used methods are sunshade net, humidifier, water curtain, Water air conditioning, fans, etc.;

Germination will also lead to rapid yellowing of leaf tips, especially many small buds, should only leave 1-2 loaded buds, others can be pinched off, this is because the temperature is high, the new buds have to grow, the roots cannot provide enough nutrients, only the old leaves through the grass to provide nutrients, the old leaves retire, leading to yellowing of the old leaves, black, note: this is not necessarily linked, yellow leaves do not equal to certain germination, germination does not equal certain yellow leaves, this to specific analysis of specific problems;

The new leaf tip yellowing black is generally caused by excessive fertilization or excessive concentration, showing that the new leaf is plump, the leaf tip is yellow, the surface is uneven, and the old leaf is yellow and dry!

Second, yellow and black leaves

Black spots appear on the leaves, and then the area gradually expands, showing a concave shape. There are often ring patterns. The junction with healthy tissues is yellow or grayish green. The tip or edge of the leaves is dry in the later stage. The dried part is generally gray. This is anthrax caused by fungi. It is infectious and can be spread with the wind, along with sick seedlings, plants, orchids, etc. Although it will not cause orchids to die, it will greatly reduce the ornamental value of orchids. It is necessary to pay attention to shade, ventilation, and spraying foliar water. Once the disease is found, the affected parts should be cut off in time to avoid becoming a source of infection, and sprayed with fungicidal drugs; there are a small number of black spots generally caused by fat water sputtering burns or unclean things attached to the surface of the leaves!

Third, the base of the leaf (bottom) yellow, yellow, rotten

1. Leaf base yellow, yellow, rot is generally caused by bacteria and fungi, leaf base appears water-stained, and then gradually browned black, from the heart leaf began to yellow, from the leaf base to the top of the spread, at the same time, pseudobulb atrophy concurrent yellow until dry, is caused by fungi stem rot disease, the bacteria are infectious, can be spread with sick seedlings, plant materials, orchid pots, etc.;

2. Leaf base appears water-like brown spots, and then rapidly expand, and finally there is a foul smell of dark brown rot patches, gently pulled off by hand is caused by bacteria soft rot, mainly wound infection and leaf core water did not evaporate in time caused by, non-infectious;

3. Yellow to light brown spots at the base of leaves, brown to dark brown rot, and spread on the surface of rhizosphere soil and stem base, destroying stems and infecting young leaves and roots, white hyphae appearing in leaf sheaths and root groups are white silk disease, which is also caused by fungi and infectious, and can be controlled by plant ash;

Orchid diseases caused by fungi are infectious diseases, bacteria caused by non-infectious diseases, fungi caused by commonly used drugs are carbendazim, chlorothalonil, methyl thiophane, potassium permanganate, etc.; bacteria caused by commonly used drugs are copper hydroxide, copper chloride, amber rubber copper and other copper preparations. The disease causing orchid yellow leaves is caused by many reasons. We need to learn more, think more, and gradually investigate to determine the disease. Only by taking targeted measures or using drugs can we get twice the result with half the effort, safe and reliable! Author: Mei Fei, founder of Orchid Bar Forum, secretary of Orchid Association of Jingshan City, Hubei Province, online celebrity of orchid industry on major self-media platforms! I will publish orchid knowledge and pictures every day, take you to understand orchids in depth, teach you to easily raise orchids, don't understand orchids can ask me at any time or leave a message below, if you like, you can pay attention to me or collect, forward to help others!