Disease Prevention and Control Methods for Fresh-Cut Lilies
I. Lily Phytophthora Blight 1. Symptoms: Stems, leaves, flowers and scales can all be affected, mainly the tender leaves of the flowers. When the leaves are affected, small water-soaked spots appear, which gradually enlarge and turn grayish-green. When the stem is affected, the water-soaked discolored part spreads upward and downward and rots, further developing into bending and drooping of the stem. In severe cases, the flower stalk and...
I. Lily Phytophthora Blight
1. Symptoms: Stems, leaves, flowers and scales can all be affected, mainly the tender leaves of the flowers. When the leaves are affected, small water-soaked spots appear, which gradually enlarge and turn grayish-green. When the stem is affected, the water-soaked discolored part spreads upward and downward and rots, further developing into bending and drooping of the stem. In severe cases, the flower stalk and scales can also be affected.
When the weather is humid, white mold layers are produced on the rotting parts of the leaves, stems and scales.
2. Prevention and control: ① Rotate with non-host plants; promptly remove and burn diseased plants found during the growing period; ② Soil disinfection. For plots where the disease occurs year after year, the soil must be disinfected before planting and management. You can use 40% formaldehyde (formalin) at 30 milliliters per square meter, diluted with water 60 to 100 times, and spray it on the seedbed, then cover the seedbed with plastic film; after 5 to 7 days remove the covering and wait 1 to 2 weeks until the medicinal smell has completely dissipated before use; or use 75% quintozene at 7 to 26 grams per square meter and mix it evenly with the soil; the soil can also be steam-disinfected for 30 to 60 minutes; ③ In the early stage of the disease, spraying Bordeaux mixture on the stems and leaves also has a certain preventive effect.
II. Lily Leaf Blight
① Symptoms: The main affected parts are the leaves and the stems of the plant; flower buds and newly sprouted young shoots can also be affected. Light brown, round or oval lesions appear on the leaves, and there is often a reddish-brown halo around the lesions. In severe cases, large lesions form, causing the leaves to dry up early; when the stems are affected, the diseased parts rot easily and break at that point. The lesions on the flowers are brown and appear as sticky rot. When young plants are affected, the growing point often dies; when the air is humid, a grayish-brown mold layer appears on the lesions of all affected parts. The rotting parts of the plant sometimes show obvious sclerotia.
② Prevention and control: (1) When cultivating lilies in a greenhouse, attention should be paid to ventilation and light transmission, and the temperature difference between day and night should not be too large; watering should be done beside the plant down to the ground, not sprayed directly onto the plant, and nitrogen fertilizer should not be applied excessively. Diseased leaves found should be removed immediately and destroyed in a centralized manner to reduce the source of infection; (2) Chemical control: In seasons when the disease is likely, you can spray 1:100 Bordeaux mixture, or 5% chlorothalonil wettable powder at 800 times dilution, or 50% carbendazim wettable powder at 800 to 1000 times dilution, or 50% benomyl wettable powder at 2500 times dilution, once every 15 days, for 3 to 4 consecutive sprays.
In addition to the above two lily diseases, flower growers should also pay attention to lily viral disease, whose symptoms generally appear as poor growth of the diseased plant and downward curling of the leaves. If this virus is found, flower growers should promptly pull out the diseased plants and burn them in a centralized manner; spraying 40% dimethoate emulsifiable concentrate at 1000 to 1500 times dilution or 50% carbaryl wettable powder at 1000 times dilution can eliminate the virus. In addition, lilies must not be interplanted with tulips. Furthermore, once flower growers find that the flowers show disease, they must consult technical personnel to clarify the condition, and then spray the medicinal solution according to the condition, so as not to spray the solution indiscriminately and affect the growth and quality of the flowers.