Main diseases of lily and their control

Lily, belongs to Liliaceae, perennial root plant, also known as wild lily, medicine lily. In recent years, lily planting is seriously threatened by diseases, such as lily leaf blight, blight, bulb base rot, virus disease and so on. The general incidence rate is 10%-15%, and the severe one can reach 20%-30%.

1. Several major diseases on lilies

The main results are as follows: (1) Lily leaf blight, also known as lily gray mold, is a common disease. It mainly harms leaves and can also infect stems, buds and flowers. The disease spot on the leaf is round, oval, of different sizes, light yellow to light reddish brown, waterlogged. Under warm and humid conditions, the disease spot becomes thin and brittle, light gray and translucent, which can cause the whole leaf to die; the stem becomes brown or constricted, resulting in the collapse of the plant; when the young plant is infected, the growth point of the stem and leaf becomes soft, rot and die; small brown spots appear at the initial stage of flower bud damage, and then expand and cause flower bud rot. Under wet conditions, a large number of gray mildew layers are produced in the disease area. The pathogen was mainly left in the soil by sclerotia and overwintered by mycelium on the diseased remains. In the following spring, the overwintering mycelium grew gray mold layer on the disease part or sclerotia, and the conidia spread through air flow to cause the first infection. The conidia on the plant disease department in the field were spread by wind and rain and spread rapidly. The suitable temperature for the growth of this strain is 22 ~ 25 ℃. Generally, there are many Rain Water in early June, the fog is heavy, and the disease spreads quickly during RH90% in the field.

(2) the diseased strains of lily virus showed mottled mosaic, light green and dark green. The diseased plants were obviously dwarfed, the scales were short, and some showed brown and necrotic spots. According to the investigation, the occurrence of virus disease has a lot to do with the source of the seed. Some of the local seeds are not detoxified, while others are introduced from the Netherlands. The price of the seed ball is very high, but the virus is still very serious. The lily virus disease planted is generally more than 30%.

(3) bulb base rot mainly harms the base of lily stem, affects plant growth and leads to the death of the whole plant. The disease is common in many areas, with an incidence of 10% to 15% and as high as 10% to 30%. The disease usually begins when the plant blossoms, the base of the plant becomes dark brown and rotten, the leaves droop and turn yellow, resulting in death. The pathogen overwintered with the disease residue in the soil and became the primary infection source of the disease. The disease is easily caused by soil flooding, viscous weight, the application of undermature fertilizer, and the harm of nematodes and underground pests. This bacteria requires high temperature and humidity, so the disease often occurs suddenly in the middle and later stage of plant growth, when the temperature rises, and when it turns sunny after continuous rain.

(4) Leaf tip blight of lily is common, which mainly harms the leaf tip, and the injured leaf tip becomes black-brown, necrotic or withered and spreads to the base of the leaf. The leaves were damaged in the middle, forming spindle-shaped or oval disease spots, brown or reddish brown edges, gray-white in the center, and many small black spots scattered on the disease. The pathogen overwintered on the diseased body or diseased plant in the field, and spread by wind and rain in the second year, invading from the wound or epidermis, resulting in disease in the field. The disease began to develop in June. It is easy to suffer from poor management of fertilizer and water and weak plant growth.

(5) Lily blight is also called lily foot rot. The disease was more serious in Rain Water years, which led to stem and leaf rot, plant lodging and affected bulb yield. Mainly harm the stem and leaves, the leaves produce water-stained gray-green to brown spots, there is no obvious edge. When the disease is serious, the flowers and bulbs show watery brown spots and rot, and the disease grows into a sparse white mildew layer when the weather is wet. Stem and stem base disease, initially waterlogged, brown wrinkle stripes, gradually upward and downward expansion, resulting in stem rot, plant wilt and collapse, sometimes tender leaves stem tip withered. The pathogen overwintered in the soil with the diseased residual tissue, and the disease was caused by infecting the host when the Spring Festival conditions were suitable in the second year. When there is much rainfall and high air and soil humidity, a large number of sporangia occur in the disease department, which is re-infected by Rain Water spatter.

2. prevention and control measures

The main results are as follows: (1) the robust and disease-free bulbs should be selected to strengthen the management of the storage period to prevent the loss of water. Virus-free bulbs should be planted to prevent virus diseases. One is through seed propagation, the other is to do stem tip treatment, take 0.1~0.2CM stem tip for tissue culture to obtain virus-free seedlings. However, virus-free seedlings must be planted in isolation and control aphids to prevent natural infection.

(2) soak the seeds with 1RU 500 thiram solution or 40% formaldehyde 50 times solution for 15 minutes before sowing.

(3) to strengthen the field management, the planting land should be high and deep ditch, and the border surface should be smooth to facilitate drainage, and wet leaves should be avoided during irrigation. Improve ventilation, light conditions, increase the application of phosphorus and potassium fertilizer, make the plant grow healthily and enhance the disease resistance.

(4) remove the diseased plant in time, thoroughly remove the diseased body on the ground, and burn it centrally. After pulling out the diseased plant, disinfect it with 50% lime milk.

(5) for chemical control, 50% carbendazim wettable powder 1000 times can be sprayed 2 times 3 times after emergence, and the diseased seedlings can be pulled out in time. For the epidemic disease, we can choose 25% metalaxyl 2000 times liquid, 40% ethyl phosphate aluminum 300 times solution, 70% dioxon powder 1000 times solution or 70% methyl thiophanate 1000 times solution. Spray the medicine all over the base of the diseased plant stem and the soil around it.