What are the main types of pests and diseases of Cymbidium sinense

(1) Fungal diseases. Root rot: such as damping-off, southern blight, etc. Due to fungal infection, the orchid roots become diseased, the root skin rots and falls off, and then neck rot and leaf base rot appear, eventually leading to death. Infected seedlings topple over and die. Black rot: caused by fungal infection, with symptoms similar to root rot. Leaf diseases: such as anthracnose, round spot disease, leaf spot disease, leaf smut, fly speck disease, rust disease, scorch disease, etc. (2) Bacterial diseases. Brown spot disease: caused by bacterial infection, makingorchidleaves form brown patches. Soft rotdisease: caused by bacterial infection of young tissues such as pseudobulbs and rhizomes, whichsoft rot, with a foul odor. The leaves lose their luster, then droop and wither. Brown rot: caused by bacterial infection, the leaves develop yellow spots that turn into brown spots; if it invades the leaf growth point, the upper part shrinks and withers. (3) Viral diseases. Due to viral invasion, sunken striped spots, stripe spots and ring spots appear on the leaves, and the orchid plant becomes stunted and deformed. The common Byras disease also belongs to this category. (4) Pests. Scale insects: scattered as white dots on the leaf surface and underside, sucking nutrients and causing the leaves to yellow and wilt. Their eggs are wrapped in a waxy coating and adhere closely to the leaf surface. Red spider mites: the body is very small and hard to find; they bite the underside of leaves, causing rust-colored spots. (5) Diseases caused by other reasons. Lack of certain elements: when deficient in elements such as nitrogen, phosphorus, iron, magnesium, molybdenum and sulfur, the leaf color deteriorates; when deficient in elements such as calcium, zinc, copper, magnesium and sodium, the orchid plant yellows or necroses. Fertilizer damage: applying undecomposed organic fertilizer or excessive chemical fertilizer, etc. will decompose and release harmful gases that poisonCymbidium sinense, and the leaves first develop black spots, and in severe cases wilt and die. Pesticide damage: improper application of chemicals can also cause dark brown spots, and in severe cases necrosis. Air and water sources polluted: this will harmCymbidium sinense, causing poor growth and death. Common harmful gases such as coal gas, coal smoke and cooking fumes, as well as acid rain, cause such damage. (Yan Xueliang)