What are the celery pests and diseases? What are the prevention and control methods?

Celery soft rot mostly occurs in the early production stage of celery transplanting or after seedling retardation. It usually starts at the base of the tender and juicy petioles. At the beginning of the disease, the lesions are light brown, water-stained, spindle-shaped or irregular, slightly concave, celery black heart disease is a complex physiological disease, and the lack of calcium in the plant is the basic cause of this disease.

Normally, the calcium content of the outer petiole of celery is its dry mass. White silk disease, also known as sclerotinia root rot, is caused by fungi and harms harvested stems close to the ground. At the onset of the disease, the base of the stem of the plant initially appears dark brown water-stained lesions, and then gradually expands, followed by white silky hyphae on the vegetable stem, and then gradually decays.

<> biological control refers to the biological control of pests and diseases using living natural enemies. At present, China is mainly used for the control of pests, and the natural enemies that can be artificially propagated and released in large quantities are Bacillus thuringiensis.

Microsporidia, entomopathogenic nematodes, insect viruses, Beauveria bassiana, red-eyed wasps, in celery production, 40% toxin + 2 is recommended. 5% cyhalothrin.

It can not only control the harm of underground pests, but also have low toxicity and small residues. At the same time, chemicals should be used alternately in the process of celery pest control.

Proper fertilization. Plantar fertilizer was applied with increased phosphorus, potassium and boron fertilizers to develop robust plants to improve disease resistance. Don't use too much nitrogen fertilizer.

and potassium fertilizers to avoid obstruction of boron absorption; Calcium supplementation should be supplemented with boron, calcium and boron supplementation at the same time, the effect is obvious, and sugar alcohols can be used.

Calcium-boron fertilizer, foliar fertilizer spraying at the celery seedling stage and growing stage. During the onset of the disease, the roots are surrounded by pentachloronitrobenction soil, that is, the medicinal soil is sprinkled on the root neck. The preparation method of medicinal soil is to mix 1 kg of quintonitrobenzene powder and 50 100 kg of semi-dry and wet fine soil.

Strengthen cultivation management. The planting should not be too dense, and attention should be paid to ventilation; Apply fully decomposed organic fertilizer, because undecomposed organic fertilizer is also a suitable source of nutrients for pathogens, which is one of the important reasons for inducing disease. It is necessary to pay attention to drainage, increase the application of phosphorus fertilizer, and potassium fertilizer, improve the disease resistance of plant beads, dig up the diseased beads in time, and then carry out soil disinfection, spray powder rust every 10 times on the lightly diseased beads, add 1000 times dilution, and spray 3 times in a row.

Leaf and stem damage symptoms: It mainly harms leaves, petioles and stems. If the leaf disease starts from the old leaves, the leaves show lesions, brown necrosis in the middle, the outer edge of the leaves is dark reddish-brown and obvious, and there will be a small number of small black spots in the middle of the leaves.

The common diseases of celery include soft rot, soft rot, virus disease, early blight, sclerotinia and so on. Control methods: Try to choose varieties with strong disease resistance before planting. Before sowing, soak the seeds in warm water at 48 degrees for about half an hour, which can effectively prevent and control the diseases brought by the seeds before sowing.

Reasonable fertilization, found that the disease is removed in time to prevent the spread. Pay attention to the circulation of air and avoid moisture. Prophylaxis can be used with drug sprays and **.

Celery spot blight mainly affects leaves, but can also damage petioles and stems. The leaves are initially light brown oil-soaked small spots, the edges are obvious, and then expand to round, the edges are brown, ** light brown to gray-brown, there are many small black spots on the lesions, and there are yellow halos outside the lesions. Low temperature and high humidity are conducive to the occurrence and epidemic of diseases, the temperature is about 20, the relative humidity is 90%, and the disease is severe in humid and rainy weather.

Seed treatment: Collect seeds without disease, soak seeds in 48 warm water for 30 minutes before sowing, which can effectively kill pathogenic bacteria on seeds. When soaking the seeds, stir constantly to heat them evenly, and then put the seeds into cold water to cool and dry the seeds.

Symptoms of celery soft rot: mainly damage the base of the petiole, and the disease can occur at the seedling stage and the adult stage. At first, there are water-ulcerated, light brown spindle-shaped or irregular sunken spots, and then they quickly open inward, and when the humidity is high, they are wet rot, and the vascular bundles become black and smelly.

Control methods: can be rotated with wheat, rice and other crops for more than 2 3 years: choose geothermal flat plots for planting, pay attention to planting density; Plantar fertilizer application, reasonable water and fertilizer management; After harvesting, remove diseased residues in the field, expose the soil to the sun, and promote the decomposition of diseased residues.

The main pests of celery are aphids, spotted loons, root-knot nematodes, etc. Aphids can be sprayed with 10% imidacloprid wettable powder 3000 times or 50% anti-aphid wettable powder 2000 times. Spotted loon flies can be sprayed with 50% latent gram wettable powder 3500 4000 times or avermectin emulsifiable concentrate 3000 times.

Root-knot nematodes can be sown or planted, and 5 kg of 10% Limanku (gram phosphorus) granules can be applied per mu of furrow or hole. During the growth period, the roots can also be irrigated with avermectin EC 1000 times.

Under general conditions, there are four methods for controlling fruit tree diseases and pests, namely manual control, biological control, physical control and chemical control methods, and their specific contents are:

Artificial control refers to the combination of cultivation management, through fertilization, soil turning, pruning, thinning flowers and fruits to eliminate pests and diseases, or according to the characteristics of pests and diseases to eliminate pests and diseases by manual killing, removal, scraping. This method is used a lot in production, and almost every pest and disease control is used. For example, in winter, clean up the fallen leaves and fruits, scrape the rough bark, cut the diseased branches, and kill the longhorn beetle, tea-winged bugs, beetles, and scaphoid caterpillars in the growing season.

<> biological control refers to the biological control of pests and diseases using living natural enemies. At present, China is mainly used for the prevention and control of pests, and the natural enemies that can be artificially propagated and released in large quantities are Bacillus thuringiensis, microsporidia, entomopathogenic nematodes, insect viruses, Beauveria bassiana, red-eyed wasps, ladybugs, lacewings, predatory mites, etc. Physical control uses various physical factors (light, electricity, heat, wind) or equipment to control pests, including trapping, trapping, blocking, and the use of irradiation technology.

For example, black light attracts insects, fruit trees are painted white to repel pests from laying eggs, and sweet and sour liquid and sexual attractants are placed in moth trap vessels. Chemical control is a method of using various chemical substances to control pests and diseases. At present, it mainly refers to the prevention and control of chemical pesticides.

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From planting to slow seedlings to small water watering, because the air is relatively dry, hot, in order to prevent celery leaf blight, spot blight, can be used Biluqing 25g, aphid lice speed gram 15g, add 30 kg of water, slow seedlings to carry out seedlings, seedlings are generally not watered, control the amount of water is generally 10-15 days, if black spot or sclerotinia is easy to occur during this period, with 50 of promethine 20g 5g of mycolecin, the period of vegetative growth is relatively vigorous, that is, after the temperature drops to 20 degrees, cabbage enters the growth period, 40 degrees below the growth of celery into the peak period, generally 50-60 days, to fertilizer water storm, Hui Manfeng flush release fertilizer 20-30 kg, at this time celery white roots have been covered with the surface, indispensable water, after the frost falls, appropriate water, or not watering, is conducive to the growth of the petiole, when the celery grows to 20-30cm when soft rot is more prevalent, with pictomycin or occtromycin 5g day up to 2116 leafy vegetable type 25g, add 30 kg of water, virus disease can be killed quickly 15ml 2116 leafy vegetables 25g, Add 30 pounds of water, spray 1 time every 15 days, use Shennongdan when cultivating the root knot nematode, and use 4-5 pounds per acre.