Orchid leaves turn from green to black as if poisoned; if you don't treat them, the whole pot will die.

I. Premature leaf decline

Normally, during the growth of orchids, in order to promote the sprouting and growth of new leaves, the tips and edges of old leaves will gradually turn yellow and wither from top to bottom, thereby saving nutrients. This is the normal phenomenon of leaf decline.

But if the new leaves are also turning yellow and scorched, and even the pseudobulb deforms and changes color, then it means the orchid leaves have declined prematurely.

What to do about premature leaf decline?

Premature leaf decline will cause orchid leaves to become sparse and turn black, and the plant to develop slowly or even stop developing. At this point, first check the state of the root system.

1. Roots only slightly damaged

If the roots are not badly damaged and the outer leaves wither and decline, just cut them off in time, then control water and fertilizer, do not water until dry, and water thoroughly when completely dry; in summer, apply a thin liquid fertilizer once every 15 to 20 days or so.

2. Roots severely damaged

If the orchid roots are severely damaged, the whole plant may decline. At this point, you must change the pot and soil. After removing it from the pot, first cut off the rotten root parts, then soak the whole root in a carbendazim solution to disinfect, then repot with growing medium, taking care to expose the pseudobulb.

II. Infection with stem rot

If you find orchid leaves gradually turning black from bottom to top, black spots growing on the leaf surface, and when you dig open the roots you can even see that everything from the root crown to the pseudobulb has turned black, then you should be on guard - it is very likely infected with stem rot!

How to prevent and treat stem rot?

The period of high incidence of stem rot is from June to September. During this period, temperatures are high, watering is frequent, and there are many pests, so orchids are prone to infection by pathogens.

Prevention first - prevention is better than cure

1. During the high-temperature period in summer, every 7 to 10 days, use carbendazim, chlorothalonil, or thiophanate-methyl and other antibacterial agents diluted 500 to 1000 times to spray and sterilize around the plant and on the leaf surface.

2. Treat wounds promptly, especially after division, immediately apply a wound-healing agent to prevent infection and disease;

3. You can bury some carbofuran insecticide in the growing medium to prevent pests from infecting the pseudobulb.

How to treat it?

1. As soon as it is discovered, immediately cut off and burn the infected orchid plants and leaves;

2. Pull out the whole pot of orchids, wash them clean, cut off the diseased plants and rotten pseudobulbs, then place the remaining whole orchid plants in a difenoconazole solution slightly stronger than 500 times, and soak for 1 whole day.

3. After drying, change the soil and repot. Do not water, place in a cool and ventilated place for three days, and once a month soak the orchid pot with a 500 to 1000 times fungicide solution, and it will gradually recover to health.

Note: Huahua reminds everyone that in high-temperature weather you must often loosen the soil and ventilate the orchids to ensure normal root respiration. If you find it troublesome, you can use a fan to blow on them after watering~

Alright, that's all for the introduction to orchids' "heat disease."

Flower lovers, have you all learned it?