Home › Nursery Stock › Article

What are the control methods for Fusarium wilt in Chinese orchids?

Nursery Stock 0 views
Symptoms: Fusarium wilt is a serious disease of Cymbidium plants. Severely affected plants die within a few weeks, while ordinary diseased plants can survive for one year or longer. The above-ground symptoms of Fusarium wilt are similar to those of root rot caused by Rhizoctonia solani Kuhn, namely leaves turning yellow and wilting, pseudobulbs becoming thin and twisted, and ultimately root rot. However, Fusarium causes a bulbous purplish-red coloration, and eventually the rhizome is also affected and turns purplish-red. When the disease is severe, the pseudobulbs undergo deep rot. Onset

Symptoms: Fusarium wilt is a serious disease of Cymbidium plants. Severely affected plants die within a few weeks, while ordinary diseased plants can survive for one year or longer. The above-ground symptoms of Fusarium wilt are similar to those of root rot caused by Rhizoctonia solani Kuhn, namely leaves turning yellow and wilting, pseudobulbs becoming thin and twisted, and ultimately root rot. However, Fusarium causes a bulbous purplish-red coloration, and eventually the rhizome is also affected and turns purplish-red. When the disease is severe, the pseudobulbs undergo deep rot.

Disease conditions:

(1) Soil temperature of 28°C, moist soil, continuous cropping in pots, transplanting or frequent root injury, and weak plant growth all lead to severe disease.

(2) Acidic soil and wounds caused by nematode feeding favor the occurrence of this disease. Below 21°C or above 33°C, disease progression is slow. The pathogen is Fusarium oxysporum Schlecht., belonging to the Deuteromycotina. The colonies are white, peach-pink, violet to purple. Microconidia are borne in aerial mycelium, gathered into false heads, very numerous, oval, elliptical, cylindrical, straight or curved. Macroconidia have thin walls, are borne on aerial mycelium, rarely on conidiophores or in spore masses, spindle-shaped or sickle-shaped, falcate-curved, elliptically curved, nearly crescent-shaped or straight, with the apical cell relatively narrow and the foot cell with a pedicel-like base. Chlamydospores have smooth or rough walls, are very numerous, borne between hyphae and between conidia, terminal and intercalary, solitary or in pairs.

Control methods:

1. Since the pathogen can both parasitize and live saprophytically, diseased plants and their remnants must be completely burned, and new pots and new soil must be used when replanting orchids.

2. In the early stage of the disease, spray 50% carbendazim wettable powder or 36% thiophanate-methyl suspension concentrate at 500 times dilution; in addition, 20% tolclofos-methyl emulsifiable concentrate at 1000 times dilution, or 10% Zhifuling aqueous solution at 300 times dilution, or 12.5% synergized carbendazim concentrated soluble liquid at 200 times dilution can be used for root drenching.

Related Articles