Symptom Identification and Control Methods of Daylily Anthracnose

Daylily (scientific name: Hemerocallis citrina Baroni), also known as golden needle vegetable and lemon daylily, belongs to the order Liliales, family Liliaceae, a perennial herbaceous plant, with roots nearly fleshy, often spindle-shaped and swollen in the middle and lower parts. Daylily is sweet and cool in nature and flavor, and has the effects of stopping bleeding, reducing inflammation, clearing heat, removing dampness, promoting digestion, improving eyesight, and calming the mind. It has therapeutic effects on vomiting blood, blood in the stool, difficult urination, insomnia, and insufficient lactation, and can be used as a restorative tonic after illness or childbirth.

Morphological characteristics of daylily

Hemerocallis plicata is a perennial herb, 30-65 cm tall. Roots clustered, fleshy, root tips enlarged into a spindle shape. Leaves basal, narrowly long and strap-shaped, overlapping at the lower end, gradually flattening upward, about 40-60 cm long, 2 cm-4 cm wide, entire, with the midvein protruding on the lower surface of the leaf. The flower stem emerges from the leaf axil, branching and flowering at the top, with several large orange-yellow funnel-shaped flowers, perianth 6-parted. Capsule leathery, elliptical. Seeds black and shiny. The plant is generally relatively tall; roots nearly fleshy, often spindle-shaped and swollen in the middle and lower parts. Leaves 7-20, 50-130 cm long, 6-25 mm wide.

The flower scape varies in length, generally slightly longer than the leaves, triangular at the base, more or less cylindrical above, branched; bracts lanceolate, the lower ones up to 3-10 cm long, gradually shorter from bottom to top, 3-6 mm wide; pedicels relatively short, usually less than 1 cm long; flowers numerous, up to more than 100; perianth pale yellow, sometimes with a dark purple tip at the bud stage; perianth tube 3-5 cm long, perianth lobes (6-)7-12 cm long, the inner three 2-3 cm wide. Capsule obtusely triangular-elliptical, 3-5 cm long. More than 20 seeds, black, ribbed, requiring 40-60 days from flowering to seed maturity. Flowering and fruiting period May-September.

Symptom identification and control of daylily anthracnose

Symptom characteristics of daylily anthracnose:

It mainly damages leaves, and can also damage flower scapes. Leaf infection mostly starts from the leaf tip or leaf margin, semicircular or elliptical, brown, with a dark brown margin, and the boundary between diseased and healthy parts is relatively clear; some lesions have a yellow halo around the outer edge. The lesions expand and coalesce into streaks, causing the leaves to become grayish brown to grayish white and dry up. In the later stage, small black dots appear on the diseased part (the pathogen's acervuli and conidia). Pathogen and disease characteristics of daylily anthracnose:

The pathogen is Colletotrichum of the Deuteromycotina, including Colletotrichum liliacearum Ferr. and C. gloeosporioides Penz. Both fungi overwinter as mycelium and acervuli on diseased plants or in the soil with diseased residues. However, in the warm South, the overwintering period is not obvious. The conidia produced on the pathogen's acervuli can be spread by wind and rain or the activity of small insects, causing infection and disease. Warm and humid weather or planting site environment favors disease development. Excessive application of nitrogen fertilizer and excessively vigorous plant growth make plants susceptible to the disease. Low-lying, humid, poorly drained plots or plots with severe leaf mite damage are also susceptible. Disease resistance differs among varieties. Among the 13 daylily varieties recently promoted in China (mostly local varieties), those generally showing relatively strong disease resistance or stress resistance include: Jingzhou Hua (Heizuizi Hua), Mengzi Hua (Bangbang Hua, Bangchui Hua), Siyue Hua (Mangzhong Hua) [the above are all local varieties from Shaodong, Hunan], Daniaozui (Huaiyin, Jiangsu), Luding (Jinyun, Zhejiang), Quxian Huanghua (Sichuan), Jinhuang Hua (Tianmen, Hubei), Shayuan Huanghuacai (Shaanxi), etc. Whether they are also resistant to anthracnose remains to be further observed and determined in various places. Control methods for daylily anthracnose:

1) Select disease-resistant varieties according to local conditions.

2) Strengthen fertilizer and water management. Spray foliar fertilizer at the appropriate time, especially rationally and timely applying spring seedling fertilizer, lotus-promoting fertilizer, bud-strengthening fertilizer, and winter seedling fertilizer, so as to coordinate vegetative and reproductive growth, keep the plants strong but not excessively vigorous, and enhance disease resistance; irrigate at the appropriate time and to an appropriate degree, pay attention to clearing ditches and draining waterlogging, and improve root vitality.

3) Spray pesticides early to control the disease. Before onset, or at the latest after symptoms appear, spray 70% thiophanate-methyl + 75% chlorothalonil (1:1) 1000-1500 times dilution, or 30% copper oxychloride + 70% mancozeb (1:1) 800-1000 times dilution, or 50% Shibaogong wettable powder 1000 times dilution, or 25% Tanteling wettable powder 500 times dilution, or 80% anthracnose Fumei wettable powder 800 times dilution, 2-3 times or more, once every 10-15 days, applied alternately, with shorter intervals earlier and longer intervals later.