What to Do When Bracken Fern Gets Damping-Off? Symptom Identification and Control Methods
Bracken fern (Pteridium aquilinum var. latiusculum), also known as fist fern, cat's claw, and dragon-head fern, prefers to grow on sunny plots in low mountain areas. It is found in most parts of China, mostly distributed in sparse coniferous and broad-leaved mixed forests. Its edible part is the unopened young tender leaf buds. After processing, bracken fern has a fresh, fragrant, and smooth taste; when mixed with seasonings, it is cool and refreshing, making it a rare top-quality dish to go with wine. It can also be stir-fried, processed into dried vegetables, used as filling, or pickled into cans. It is widely distributed in mainland China and Southeast Asia, and is also welcomed on dining tables in these regions.
Bracken fern is a deciduous herbaceous plant of the Pteridaceae family. Bracken fern generally grows to a height of one meter, with long creeping rhizomes covered in dark brown hairs. In early spring, new leaves emerge curled in a fist shape, appearing three-forked. The stalks and leaves are fresh and tender, covered with white hairs; this is the collection period. The petiole is 30-100 cm long, and the blade is triangular, 65-150 cm long and 30-60 cm wide, with 2-3 times pinnate division. The lower pinnae are opposite, and brown sori are continuously borne along the leaf margins, with double indusia. It mostly grows on sunny slopes in mountainous areas with moist, fertile soil and relatively deep soil layers.
The tender leaves of bracken fern contain potassium, calcium, magnesium, pterosin, pteroside, acetylpterosin, choline, and sterols. In addition, bracken fern also contains 18 kinds of amino acids, etc. Modern research suggests that the cellulose in bracken fern can promote intestinal peristalsis and reduce the absorption of fat by the stomach and intestines. Bracken fern is sweet in taste and cold in nature; as a medicine, it has effects such as detoxification, clearing heat, moistening the intestines, and resolving phlegm. Regular consumption can lower blood pressure and relieve dizziness and insomnia. Bracken fern can also stop diarrhea and promote urination. The dietary fiber it contains can promote gastrointestinal peristalsis, has the effect of descending qi and relieving constipation, clearing the intestines and eliminating toxins, and can also treat rheumatoid arthritis, dysentery, hemoptysis, and other diseases. It also has a preventive effect on measles and influenza.
Symptoms and control of bracken fern damping-off
Bracken fern damping-off is a common disease at the seedling stage. It mostly harms middle- and late-stage seedlings, commonly known as dead seedlings and moldy roots. In severe cases, it causes patches of dead seedlings. It occurs throughout the country.
What is damping-off? Damping-off, also called “dead seedlings”, is mainly caused by infection by Rhizoctonia solani Kuhn (scientific name Rhizoctonia solani Kuhn, English name Sheath Blight), a fungus of the Deuteromycotina. It has a wide host range. In addition to Solanaceae and cucurbit vegetables, some legumes, crucifers, and other vegetables can also be harmed. It is known that more than 160 species of plants can be infected.
Symptoms of bracken fern damping-off:
It mostly occurs in the middle and late stages of seedling raising. It mainly harms the base of the seedling stem or the underground root system. At first, oval or irregular dark brown lesions appear. Early diseased seedlings wilt during the day and recover at night. The diseased part gradually becomes sunken and constricted, and some gradually turn dark brown. When the lesion expands and encircles the stem for one full circle, the plant finally dries up and dies, but does not lodge. Mildly diseased plants only show brown sunken lesions and do not die. When the seedbed humidity is high, an inconspicuous light brown spiderweb-like mold can be seen on the diseased part.
Control methods for bracken fern damping-off:
1. Pay attention to the selection of seedbed land. Choose fields with high and dry terrain, convenient drainage and irrigation, shelter from the wind and facing the sun, fertile and loose soil, and no pathogens.
2. Strict soil disinfection. For old seedbeds or nutrient soil that may carry pathogens, soil disinfection treatment is required. Use 50% carbendazim wettable powder for disinfection, using 8-10 grams per square meter of seedbed. First mix the medicinal soil evenly with an appropriate amount of fine dry soil, then spread 1/3 of the medicinal soil onto the bed surface. After sowing, spread the remaining 2/3 of the medicinal soil on top of the seeds, and finally cover with soil to complete sowing.
3. Strengthen seedbed management. Sow evenly, with appropriate spacing, and apply water at the right time and in the right amount. Avoid low temperatures and high temperatures, and do not water on cloudy and rainy days.
4. Chemical control. For those that develop the disease after emergence, you can choose 75% chlorothalonil wettable powder 600 solution, 64% oxadixyl wettable powder 500 solution, etc., spraying once every 7-10 days, for 2-3 consecutive sprays.