Bacterial soft rot

Symptoms of soft rot: is a disease caused by bacteria, the pathogen is soft rot Escherichia coli, generally from the new seedlings in the same year to start the disease, if not timely control, the whole basin can be infected. Waterlogged dark brown necrotic plaques were produced in the leaf base in the early stage of seedling susceptibility, and the whole leaf base became black and wet rot after a few days, and the rot was aggravated in about a week, and the whole seedling was easy to pull up. The disease is characterized by leaf base decay, smelly, leaf tip generally asymptomatic, and will show dehydrated or watery patches on the leaf surface in Shanghai. Once the orchid is infected, there is generally no cure, so the disease can only be controlled and not allowed to spread.

Occurrence characteristics: the disease overwintered in the diseased and residual tissue and bacteria-carrying matrix, and invaded from the orchid wound and natural orifice with water droplets under suitable conditions, the disease was the most serious from May to June every year, and the disease was easy to spread under the condition of high temperature and humidity. The disease can be easily induced by poor permeability of culture medium, partial application of nitrogen fertilizer and continuous high temperature and rain.

Prevention and treatment: mainly prevent, usually pay attention not to be too wet, keep ventilated, do not water the new seedlings during the growing period, ventilate in time after watering and spraying, keep the leaf base dry, if infection is found, pour out and clean up the diseased tissue, soak the orchid root and bulb in disinfectant, remove and dry in 1-2 hours, apply ointment to the wound and plant it in a wet and dry substrate. When planting, the bulb should be exposed 1-2 cm and placed in a cool and ventilated place. Hydrogen should be sprayed on the leaves or irrigated 2-3 times in 7-10 days, and the disease should be observed in time. If there is a tendency to spread, it should be poured out and then disinfected until the disease is completely under control.

Control agents:

95% dimethazone 1000 times solution

1000 times solution of 50% Dysenamine

75% agricultural streptomycin 500-800 times solution

20% Ye Kuning 1000 times liquid

Author: Xu Maojin