Incidence regularity and control measures of stem rot of potted orchids

Stem rot of potted orchids, also known as Fusarium wilt and Fusarium wilt, is one of the most troublesome diseases in orchid species. The pathogen of orchid stem rot is Fusarium (fungus), which may occur as early as February. The peak period of orchid stem rot is from May to September. In severe cases, it will cause orchid stem rot and atrophy until the plant dies.

I. harmful symptoms

After the orchid gets sick, the base of the heart leaves of the old or new seedlings begin to turn yellow, which will wither and dry to death within 1-2 days. If the pot is poured at this time, it can be found that the root system of the diseased seedling is still intact, and even the crystal head exists, and the new buds issued in that year are also intact. But if you cut the false bulb of the diseased seedling with a knife, you will find that the inside of the false bulb has turned brown, even rotten. If we continue to cut the false bulbs adjacent to the diseased seedlings, we can also find that those seedlings that look green and look intact have already been infected (brown) inside the false bulbs, and it is only a matter of time before the disease occurs. From this point, it can also be seen that the spread of stem rot is very hidden.

Second, the law of the disease.

Stem rot is easy to occur in the environment of high temperature and humidity, hardening of plant materials and poor ventilation. The pathogen of stem rot overwintered mainly as mycelia and thick-walled spores in the plant material, and it will become the source of primary infection in the second year. The pathogen is transmitted through bacteria-carrying plants and orchid seedlings, invades from the root wound or natural orifice of orchid plants, infects the vascular bundles of orchid plants, and propagates in large numbers, and then blocks the water channel of orchids, causing orchid plants to die due to dehydration and lack of nutrition.

III. Prevention and control methods

1. Deal with the wound of orchid plant in time, and apply wound healing agent or broad-spectrum fungicide immediately after orchid split to prevent infection.

2. cut off the diseased seedlings and destroy the diseased plants in time.

3. Put the orchid pot in a ventilated place.

4. During the period of high incidence of stem rot, the medicine was poured into the basin every 15 days, and the main drugs can be selected: 75% sodium sulfonate soluble powder 800-1000 times, 25010 prochloraz EC 800-1000 times, 70%? 800 times liquid of carbendazim wettable powder.