Common diseases of flowers and their control

Common diseases and hazards

In the process of growth, flowers often encounter the infection of pests and the influence of adverse environment, which makes a series of pathological changes in physiology and external morphology, resulting in the decline of the quality and yield of flowers. this phenomenon is called flower disease. There are many causes of flower disease, which are mainly caused by the infection and adverse environment of harmful organisms such as fungi, bacteria, viruses, mycoplastids, nematodes, algae, mites and parasitic seed plants. The flower diseases caused by these different causes are called fungal diseases, bacterial diseases, virus diseases, nematode diseases and physiological diseases (or non-infectious diseases).

1. Fungal diseases

Fungal diseases are caused by fungi. Fungi are a class of lower organisms without chlorophyll, with individuals of different sizes, most of which can only be seen under a microscope. The development of fungi can be divided into two stages: nutrition and reproduction. The hyphae are vegetative, and asexual and sexual spores are vegetative. They mainly spread through the seedlings of wind, rain, insects or flowers, and invade the body through natural pores such as stomata, water pores, lenticels and various wounds in the epidermis of flowers and plants, and can also directly invade the harmless epidermis. The diseased site showed symptoms such as white powder, rust powder, coal dirt, spots, rot, wilt, deformity and so on. There are mainly rose black spot, powdery mildew, chrysanthemum brown spot, peony red spot, orchid anthracnose, rose rust, flower seedling blight and so on.

2. Bacterial diseases

Bacterial diseases are caused by bacteria. Bacteria are smaller than fungal individuals and are a class of lower, single-celled organisms whose morphology can only be observed under a microscope. They are generally spread by means of Rain Water, running water, insects, soil, seedlings of flowers and remnants of diseased plants. Mainly from the plant surface stomata, lenticels, water pores, nectaries and various wounds invaded the flowers, causing harm. It is characterized by spots, ulcers, wilting, deformities and other symptoms. The common bacterial diseases are bacterial root cancer of cherry blossoms, bacterial perforation of green peach and bacterial soft rot of Iris and cyclamen.

3. Virus diseases

Viral diseases are caused by viruses. In recent years, virus disease has risen to a position second only to fungal diseases. virus is a kind of parasite which can harm many kinds of precious flowers, such as daffodils, orchids, carnation, lilies, dahlias, tulips, peonies, peonies, chrysanthemums, gladiolus, African chrysanthemum and so on. Its symptoms are chlorosis, curling leaves, deformity, short clump, necrosis and so on. The virus is mainly transmitted through piercing insects, grafting and mechanical damage, even in pruning, cutting flowers, weeding, hands and gardening tools contaminated with virus juice, can play a role in transmission. Common are tulip virus disease, cyclamen virus disease, a series of red mosaic virus disease and chrysanthemum, Dahlia virus disease and so on.

4. Nematode diseases

Nematode diseases are caused by nematodes. Nematodes are low-grade animals with a small body. Generally slender cylindrical, pointed at both ends, similar to the familiar Ascaris lumbricoides, a few species of female worms are pear-shaped. There is a spear-shaped snout needle in the head and mouth of the nematode, which is used to pierce plant cells to absorb juice. Nematode diseases mainly damage flowers such as Compositae, Primulaceae, Rosaceae, Impatiens, Begoniaceae and so on. The main symptom of the disease is the production of tumors of different sizes on the host host root and lateral root. Common are cyclamen, impatiens, peony, rose and other flowers and trees of root-knot nematode disease.

Timely prevention and treatment of symptoms

Among the flower diseases, fungal diseases are the most common, widely distributed and harmful. In recent years, the harm of virus disease and nematode disease is becoming more and more serious, which has become one of the important reasons for the degradation and quality deterioration of flower varieties. There are many kinds of flower diseases, which are briefly classified according to different control methods.

1. Prevention and control of fungal diseases

(1) diseases such as powdery mildew, anthrax, black spot, brown spot, leaf spot, gray mold, etc.: first, remove dead branches and leaves in early spring or late autumn and cut off diseased branches and leaves in time; second, spray 65% zinc 600 times before onset; third, reasonable fertilization and watering, pay attention to ventilation and light; fourth, spray more than 50% carbendazim or 50% thiophanate 500-600 times, or 75% chlorothalonil 600-800 times. (2) Rust: in addition to the above 1 ~ 3 methods, spray 97% sodium rust 250 ~ 300 times (add 0.1% washing powder), or 25% trimethoprim 1500 times, 2500 times. (3) Rhizoctonia solani and root rot: first, soil disinfection, treating the soil with 1% formalin or steaming the cultivated soil in a pot for 1 hour; second, watering should be dry and wet to avoid stagnant water; third, at the initial stage of the disease, the rhizosphere was irrigated with 50% benzoylammonium 300-400 times solution, with 2 kilograms / square meter. (4) White silk disease, Sclerotinia sclerotiorum: first, use 1% formalin or

Treat soil with 70% pentachloronitrobenzene, about 5 g ~ 8 g / m2 of pentachloronitrobenzene, mix 30 times fine soil and apply it into the soil; second, select disease-free seedlings or soak in 70% topiramate 500 times solution for 10 minutes before planting; third, implement crop rotation to avoid continuous cropping; fourth, watering should be reasonable and drainage should be timely after rain. (5) soot disease: after the disease, scrub the diseased branches and leaves with clean water and spray 50% carbendazim 500 ~ 800 times solution.

2. Prevention and control of virus diseases

Prevention and treatment of virus diseases should be focused on prevention and comprehensive prevention. The main control measures are as follows: the selection of excellent varieties with disease tolerance and resistance is the fundamental way to control virus diseases. Strictly select non-toxic breeding materials, such as roots, tubers, bulbs, seeds, seedlings, cuttings, scions, rootstocks, etc.; eradicate weeds and reduce the source of virus infection; spray 1000-1500 times of 40% dimethoate emulsion to eliminate aphids, whiteflies and other infectious insects; remove and burn diseased plants in time, and wash hands and tools that have come into contact with diseased plants with soapy water to prevent human contact. For example, the general seeds can be soaked in 50 ℃ ~ 55 ℃ warm soup for 10 ~ 15 minutes, strengthen cultivation management, pay attention to ventilation and light transmission, reasonable fertilization and watering, promote flower growth and health, and reduce the damage of virus disease. 3. Control of bacterial diseases.

(1) soft rot: first, the storage site should be disinfected with 1% formalin solution and pay attention to ventilation and drying; second, rotation should be carried out, and the potted plant had better change the new culture soil once a year; third, timely pest control, phoxim and other pesticides should be selected to control underground pests; fourth, the rhizosphere soil of diseased plants should be irrigated with 600-800 times solution of dimethazon in time after onset of the disease. (2) Root cancer: first, select disease-free seedlings or rotate the soil or treat the soil with pentachloronitrobenzene, and turn it into the soil with 6 ~ 8 grams of fine soil with 70% powder per square meter; second, remove the disease immediately after the disease and disinfect it with 0.1% mercury water. (3) bacterial perforation: the first is to spray 65% Dysen zinc 600x solution before the onset of the disease; the second is to remove the affected site in time and destroy it; the third is to spray 50% methamphetamine 800 times, times ~ 1000 times at the initial stage of the disease.

4. Nematode disease control.

(1) implement crop rotation. This is a very effective prevention and control measure. (2) improve the cultivation conditions. Turning the soil several times in summer can eliminate a large number of pathogenic nematodes, remove diseased plants, diseased bodies and wild hosts, and fertilize and water reasonably to make the plants grow healthily. (3) soil disinfection. The cultivated soil was steamed in a steamer for about 2 hours. (4) Hot water treatment. Soaking the infected parts for reproduction in hot water (10 minutes at 50 ℃ and 5 minutes at 55 ℃) can kill nematodes without harming the host. (5) Drug prevention and treatment. Use 3% carbofuran granules of about 25 grams per square meter (this drug is a highly toxic drug, you must pay attention to safety when using it), apply it evenly into the soil, cover it with soil about 10 cm thick, water thoroughly, and have a validity period of about 45 days. And can also control a variety of other pests (aphids, red spiders, shell insects, underground pests, etc.)