Ferns have relatively few pests and diseases, but most ferns like to grow under high temperature and high humidity conditions, and pests and diseases are inevitable. In the process of cultivation and management, we must also prevent and control in order to enhance the ornamental effect.
1. Infectious diseases are caused by germs, causing various lesions on the ferns and affecting their appearance. Serious harm can also lead to death. There are mainly anthrax, brown spot, nematode, rust, coal contamination, and damping-off.
1. Anthrax. Fungal diseases, characterized by pink sticky spots at the lesions, mainly harm the young leaves of the plants. The affected area begins to have a water-stained round, near-circular, dark brown spot on the leaf margin or tip, and then gradually expands into irregular plaques from several lesions. The color changes to burnt yellow and some lesions become Cloudy, with a light red halo around the edge, the middle of the late lesion turns gray, there are many tiny black spots, and the entire leaf dies when severe. The soft growth point of the Boston Fern is affected by this pathogen, and the top becomes brown and wilting, damaging the appearance of the plant's products. The pathogenic bacteria live on the diseased leaf with mycelia, conidia, or ascospores. When the temperature rises to 20°C and the relative humidity exceeds 75%, the onset of disease occurs. The pathogens are transmitted by rainwater at 25°C and the humidity is 80% to 90%. It spread quickly. Prevention and treatment: The disease is mainly prevention. Spraying should be prevented during the rainy season and high temperature and high humidity season when new leaves form. Adjust the temperature, humidity and ventilation conditions of the greenhouse, keep the leaves dry, eliminate the introduction of diseased plants, and completely remove the nearby diseased bodies to prevent the occurrence of the disease. In the premorbid or early onset, spraying once every 7 days, even spraying 2 or 3 times, can receive good results. The effective agents are 75% chlorothalonil 500 times, 50% carbendazim 800 to 1000 times, or 70% thiophanate WP 800 to 1000 times. Daiso, Lydex, Sulfobacillus, etc. The agent also has a good control effect.
2. Brown spot. The fern brown spot, also known as leaf spot or leaf blight, often occurs at the tip of the leaf. The initial stage of the diseased leaf is a round black spot, which expands into a round or near-circular shape. The lesion's edge is dark brown and central. Gray and black with small black spots, the lesions expand rapidly thereafter, and the leaves eventually turn black and die. The main route of transmission is defoliation, which can occur in spring, summer and autumn, and is popular in hot and humid seasons. Prevention and control: The diseased plants should be immediately isolated and sprayed, or cut off and focused on burning, and sprayed for protection. Can be used 50% carbendazim 1000 times, 50% thiophanate-methyl 1000 times, 200 times Bordeaux mixture and other agents spraying control. Excessive watering or excessive humidity can also cause brown spot. At the early stage of disease, it can be sprayed with a 50% solution of 300-400 parts of gentesonamide, 300-400 times of solution, and 70% of TOPZIN WP 800-1000 times.
3. Nematode disease. Also known as root-knot nematode or root-knot nematode, the pathogen is a white, line-shaped, sharp-edged mollusc. The diseased plant had brown spots and wilted. A variety of greenhouse ferns are affected by nematodes and can be identified by reddish-brown or blackish bands that extend from the middle ribs to the edges of the leaves. A small piece of brown plaque was placed in water and observed under a microscope, and the small worms were clearly seen moving around. Prevention: Clearing the damaged leaves and eliminating their growth conditions will help reduce nematode infestation. With 10% grams of pyrethroids, chlorhexidine, or 25% pyrophosphorus and other insecticides, the application of fresh loess covering the soil, a small amount of water, can significantly reduce the root-knot nematode population density. It is also useful for hot water treatment of nematodes against nest ferns. Soak the plants with hot water at 43°C for 10 to 15 minutes before planting.
4. Rust. Rust can occur in the fern crest grass and other species, it from March to April each year in the young leaves on the opposite side of the veins to produce spores, invasive plants and produce sexual spores and rust spore devices. In May, light yellow powdered uredia spores are emitted from the leaves, and brown phospores are produced. If a large number of spores invade the plants, the plants will grow poorly.
Prevention: Use 65% dexamethasone WP 500 times, 1:1:50 Bordeaux, etc. to control, spray once every 10 to 15 days, even spray 3 to 4 times, can achieve a certain effect.
5. Coal pollution. The leaves of ferns are covered with spores and mycelia of black mold, usually grown on honeydew secreted by scale insects and other sucking insects. Nicotine and soap should be sprayed repeatedly to prevent scale insects and other thorny insects.
6. Stumble. This disease is caused by two or three different fungi that cause the original leaves to become soft and black and disintegrate, often occurring when sowing fern plants. The spores of ferns should be sown on soils treated with steam sterilization, or soil treated with ground pine solutions, to help prevent damping-off.
Second, physiological disease 1. Sunburn disease. Most ferns are warm and half-shade, and they are not resistant to light. The light intensity is preferably 1000-6000 Lx. Strong direct sunlight will cause the leaves to shrink and dehydrate, withered or defocused. Prevention methods: In the semi-negative state, supplemented with 2~3 hours of sunshine, the leaves of fern leaves can be kept green; in addition to the leaves that are already burnt, besides cutting to keep the leaves in order, they should be carefully maintained to avoid strong light. stimulate.
2. The humidity is out of adjustment. The air is too dry and it is easy to cause curling of the leaves. Therefore, it takes more water to grow in the spring and summer. But fern cultivation soil in summer should not only keep it moist, but also not be too wet, so as not to cause poor root growth; watering should be controlled at the end of autumn to keep it slightly moist; water spray should be reduced during the dormancy period to avoid rotten leaves.
3. Temperature does not apply. 1 high temperature hazards. Most ferns require an optimum temperature of 18-25°C. The short-lived high temperatures in midsummer will also cause fern leaves to wilt and burn. Therefore, starting from late April, the temperature should be reduced by covering the shade, ground watering and ventilation measures. 2 cold hazards. The temperature of semi-hardy ferns like Adiantum fern should not be lower than 5°C, and the non-dwarf ferns such as trigeminal fern, bird nest fern and tumor fern should not be lower than 10°C. The temperature is too low and the leaves are injured, causing wilting, darkening, and even plant death. Coverage, smoke, and more warm fertilizers can be used to ensure safe wintering.
4. Malnutrition. 1 deficiency syndrome. The lack of nitrogen, potassium, calcium, magnesium, sulfur and other elements in the soil can easily cause abnormal fern growth and development. The fern fern, silver fern fern, and cypress, such as ferns, can be mixed in the cultivated soil with a small amount of lime, bone meal or broken eggs (shellfish) shells. Acer palmatum, fern fronds, bird's nest ferns, black ferns and other fern ferns, should be regularly sprayed with 0.1% to 0.2% ferrous sulfate solution or combined with fertilizer and fertilizer. 2 excess disease. Mainly refers to excess of nitrogen, phosphorus, manganese, boron and other elements. When the fertilizer is seriously damaged, it can be rescued by flushing water. The specific method is to loosen the soil and use a long-flowing tap water for half-day flushing. Normal flushing can be effective 1 or 2 times. Production should pay attention to the number of fertilization and fertilizer concentration, try to use long-lasting manure fertilizer, such as manure, bone meal, cake fertilizer, grass ash, etc., in order to maintain the vigorous growth of ferns.
Third, common insect pests
The main insect pests of ferns include scale insects, aphids, red spiders, and cockroaches. 1. Scale insects. Among the various scale insects, brown soft-cockroaches and clip-on peaches are the most dangerous, and other species of cockroaches are rare. Scale insects parasitic on the edge of the fern leaf or the back of the leaf, its larval period is very short, slow action, when it moves to the back of the leaf, it begins to crust, sucking the plant juice with a sucking mouthparts. Scale insects reproduce faster. When the insect population is large, it will inhibit plant growth and cause plants to wither. In severe cases, the whole plant will die with yellow leaves and induce coal contamination. Damaged leaves have spots that affect growth and viewing. The adult female insects can continuously produce the young scale insects, and the larvae can grow into adults within two months. The early-incubation young nymphs have poor drug resistance. This is a critical period for chemical control. There is no cure for specific drugs, but prevention is generally the main method. Should pay attention to inspection, keep the environment ventilated. When planting ferns, it is necessary to control the foliage not to get too wet, and often check the front and back sides of the leaves. When a small amount of insects occur, artificial brushing can be used; in late May, the scale insects hatch, and 40% omethoate can be used at this time Emulsion, 50% of malathion, 25% of iminophos, 80% of dichlorvos emulsion 1000 times spray control. Malathion sprays are extremely effective against crawling stage scale insects. Repeated spraying of nicotine and soap can also remove scale insects. When the pest is severe, cut the entire leaf and incinerate it. A few ferns have an allergic reaction to organic phosphorus and should be tested before application. Attention should also be paid to the use of red mussels and other natural enemies.
2. Locusts. Black worms and green worms are common in locusts and usually occur in early spring and early summer. They often live in young shoots of ferns. When sucking, use a sucking mouthpart to suck the juice in the plant so that the plant grows stagnant and the leaves turn yellow. In addition, the larvae's secretions often incur a variety of mold parasites and are prone to coal pollution. For prevention and treatment, wash with soap and water first, then spray 40% dimethoate or omethoate 1000-1500 times, kill 2,000-3000 times of pyrethrin, 2.5% rattan extract 1000-1500 times, and enemy 100 Insect 1000 times liquid and other prevention and treatment.
3. Red spider. Red spiders are crickets, small in size and fast in reproduction. They can breed for about 10 generations a year. The red spider sucks the sap of the fern by sucking and sucking mouthparts to make the plant grow stagnant and the leaves yellow. Due to the small size and rapid reproduction, the naked eye is harder to find. If the control is not timely, the damage will be very serious. High-temperature continuous use of dicofol 800 ~ 1000 times, 50% omethoate 1000 times alternately control.
4. Hey. Also known as snout, it is a gastropod, a family of cicadas, and a snail that is shaped like a shell. The shell usually degenerates and the mantle coats the entire back. Two pairs of antennae, the second pair of top eyes. The lungs open to the right side of the body and the body secretes mucus, leaving behind silver-white streaks after crawling. In early summer, white eggs are produced under the bark and under the stone. Earthworms are one of the major pests that damage ferns. They are often hidden in the inner wall of the pots, at the bottom of the leaking holes at the bottom, or under the cover of the plant's base and soil surface. They like to come out at night to move and eat young ferns. Tender foliage. Can be sprayed at the time of 22 to 23 at night for 70 to 100 times of ammonia to control, and can achieve the purpose of fertilization. Manual capture can also be used. The larvae have a good regenerative ability, and the captured quail is thrown into hydrochloric acid solution to kill. In the warm and humid environment, in addition to earthworms, there are also a large number of small animals such as snails, rats and cats, and wild fern leaves; while the earthworms devour fern roots and cause their growth to stagnate. It can be used for spraying and destroying snails, snail powders, mida snails or lime, and can also be used to prevent and treat ammonia water, high-concentration salt water, copper sulfate, etc., and can also be manually killed.
Fourth, the hazards of crickets and lichens
These plants do not directly harm the ferns, but they can cause shading and affect on the original leaf and plantlets of the ferns. They spread quickly and spread the ground quickly, preventing water and nutrients from entering the soil and affecting the growth of ferns. Treatment: Disinfect the soil with distilled water before sowing the spores so that the soil is not contaminated by other spores. In addition, unclean watering equipment is also one of the sources of pollution. Provide suitable temperature and fertilizer, so that the fern original progeny quickly grow and mature to reduce the impact of other spores plants, is a good way to avoid harm.
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