How to prevent and control bacterial soft rot in orchids? Sharing practical experience

Bacterialsoft rotThe main pathogen of the disease is Erwinia carotovora (Erwinia carotouoraE.): the peak incidence of this disease is during the rainy season when new shoots emerge. Brown water-soaked small spots appear at the base of infected young leaves, and the lesions rapidly expand and densely merge into patches, while also spreading to the leaf sheath and the growth point of the shoot. Leaves that are about to mature are also often infected, and the pseudobulbs are endangered. The base of infected leaves rots and gives off a foul odor, while the upper part appears dehydrated and wrinkled. This pathogen can harm all species of Chinese orchids as well as Cattleya, Oncidium, Odontoglossum, Phalaenopsis, Vanda, and others, and the disease is more severe in southern China. It mainly harmsorchidleaves and pseudobulbs. After the leaves are infected, water-soaked small spots appear in the initial stage, then gradually turn brown or nearly black, and rapidly expand, eventually developing into a soft, foul-smelling rotting mass with exudate flowing out, which spreads with rainwater or watering. If the pseudobulbs are infected, water-soaked lesions also appear, ranging from brown to black, and eventually the pseudobulbs become soft, shrunken, and dark, and rapidly rot. Bacterial soft rot mostly occurs in the early summer rainy season and spreads through wound infection, breakage from knocking, insect bites, and other means. When temperatures are high and there is abundant rain or poor ventilation, the disease is especially severe, and it develops very rapidly, usually causing an entire leaf to rot within 3-5 days. Whether it occurs on old leaves or new leaves, it is quite lethal. To prevent and control bacterial soft rot, attention should be paid to maintainingcultivationan environment with good drainage and ventilation and sufficient sunlight. If lesions are found, they should be removed and destroyed immediately. If the lesions have developed to the growth point, the entire plant should be isolated together with its pot, and misting should be avoided as much as possible, switching instead to watering the pot surface. After the diseased tissue is cut away, the diseased leaves should be pruned promptly, the wounds should be smeared with Bordeaux mixture, and the orchid plant should be soaked in a 0.1% potassium permanganate solution for 5 minutes, rinsed with running water, then sunned in sunlight for 15 minutes, and planted after drying. A 0.5% Bordeaux mixture, or 200 mg/L agricultural streptomycin, or methyl parathion, etc., can also be sprayed, all with good results. Depending on the specific situation, regular spraying at ordinary times with 30.3% tetracycline 2000-fold solution, or 10% streptomycin-tetracycline 1000-fold solution, or 68.8% Duobao streptomycin 1000-fold, all have significant preventive and therapeutic effects. At the same time, may——orchid enthusiasts harmed by “bacterial soft rot” quickly escape “the sea of suffering.”