Occurrence, prevalence and harm of calamus disease

The suitable growth temperature of Fusarium oxysporum is 20 ℃-30 ℃. At this temperature, a large number of conidia can be produced for primary and secondary infection, while thick permanent spores that can survive for many years in the soil can be formed under unsuitable conditions. Fusarium is a typical soil parasite, so the part of infecting and parasitizing the host plant is mainly the rhizome of the underground part. When we buy whole pots of bluegrass with soil germs, the pathogens are brought into the orchid nursery. When the ramets are taken apart, the bacteria attached to the soil invade the orchid plant along with the incision of the plant, and the root wound invades the orchid plant and lurks. From April to June, the weather is suitable for high temperature and humidity, and it spreads with Rain Water or watering splash.

In Guangdong, it started in early April, broke out in late May, and peaked in early June. With the arrival of high temperature in July, its expansion was restrained to a certain extent. Extracted from "Orchid Treasure Book" Hu Yingdong of Shunde National Orchid Association