What are the common disease control methods for flowers?

Bacterial diseases and their control. Common bacterial diseases of flowers mainly include soft rot, crown gall and bacterial shot hole, etc. ① Control of soft rot: First, the storage site should be disinfected with 1% formalin solution and kept well ventilated and dry. Second, practice crop rotation; for potted plants, it is best to replace the growing medium with fresh soil once a year. Flower diseases can be broadly divided into four major categories: fungal diseases, viral diseases, bacterial diseases and nematode diseases.

Fungal diseases and their control. There are more than a dozen common fungal diseases of flowers, which are grouped below according to different control methods: ① Control methods for powdery mildew, anthracnose, black spot, brown spot, leaf spot, gray mold and other diseases: First, in late autumn or early spring, clear away dead branches and fallen leaves and promptly prune out diseased branches and leaves, then burn them. Second, before the disease appears, spray 65% zineb 600x solution for protection; Third, fertilize and water reasonably, and ensure ventilation and light penetration; Fourth, in the early stage of the disease, spray 50% carbendazim, or 50% thiophanate 500-800x solution, or 75% chlorothalonil 600-800x solution. ② Control methods for rust disease: In addition to the above methods 1-3, after the disease appears, spray 97% sodium dichromate 250-300x solution (with 0.1% laundry detergent added), or 25% triadimefon 2000-3000x solution. ③ Control methods for damping-off and root rot: First, soil disinfection, treating the soil with 1% formalin or steaming the growing medium in a pot for 1 hour; Second, water only when the soil is dry and stop when it is moist, avoiding waterlogging. Third, in the early stage of the disease, drench the root zone with 50% amobam 300-400x solution, using 2 kg-4 kg of solution per square meter.

④ Control methods for southern blight and sclerotinia rot: First, treat the soil with 1% formalin solution or 70% quintozene, using about 5 g-8 g of quintozene per square meter, mixed with 30 times its volume of fine soil and worked into the soil; Second, choose disease-free seedlings or soak them in 70% thiophanate 500x solution for 10 minutes before planting; Third, practice crop rotation and avoid continuous cropping; Fourth, water reasonably and drain promptly after rain. ⑤ Control methods for sooty mold: After the disease appears, wipe the diseased branches and leaves with clean water and spray 50% carbendazim 500-800x solution.

(2) Viral diseases and their control. In recent years, viral diseases have risen to a position second only to fungal diseases. They can harm many valuable flowers, such as narcissus, orchids, carnations, lilies, dahlias, tulips, tree peonies, herbaceous peonies, chrysanthemums, gladioli, gerberas and so on. Their symptoms include mosaic, yellowing, leaf curling, malformation, stunting, necrosis and so on. Viruses are mainly transmitted through piercing-sucking insects, grafting, mechanical damage and other routes. Once the disease occurs, it is very difficult to control, so controlling viral diseases requires even more attention to prevention first and integrated control. The main measures for controlling viruses are: selecting excellent varieties that are tolerant and resistant to disease is the fundamental way to control viral diseases; strictly selecting virus-free propagation materials, such as tuberous roots, tubers, bulbs, seeds, seedlings, cuttings, scions, rootstocks and so on; eradicating weeds to reduce sources of virus infection; spraying 40% dimethoate emulsifiable concentrate 1000-1500x solution at the appropriate time to eliminate virus-transmitting insects such as aphids and whiteflies; promptly pulling out and burning diseased plants when found, and washing hands and tools that have touched diseased plants with soapy water to prevent artificial contact transmission; heat treatment, for example, ordinary seeds can be soaked in warm water at 50°C-55°C for 10-15 minutes;

Strengthen cultivation management, pay attention to ventilation and light penetration, fertilize and water reasonably, and promote vigorous flower growth, which can reduce virus damage.

Third, control pests in a timely manner; from early spring, pay attention to using phoxim and other pesticides to control underground pests. Fourth, after the disease appears, promptly drench the root-zone soil of diseased plants with dexon 600-800x solution. ② Control of crown gall: First, at planting time, use disease-free seedlings first, or practice crop rotation, or treat the soil with quintozene, using 6-8 g of 70% powder per square meter mixed with 0.5 kg of fine soil and turned into the soil. Second, after the disease appears, immediately cut out the galls and disinfect with 0.1% mercuric chloride water. ③ Control of bacterial shot hole: First, before the disease appears, spray 65% zineb 600x solution for prevention. Second, promptly remove and destroy affected parts. Third, in the early stage of the disease, spray 50% thiram 800-1000x solution.

(4) Nematode diseases and their control. Nematode diseases mainly harm flowers of the Asteraceae, Primulaceae, Rosaceae, Balsaminaceae, Begoniaceae and other families. Their main symptom is the production of tumor-like growths of varying sizes on the host's main roots and lateral roots. Control methods: ① Practice crop rotation; this is a very effective control measure. ② Improve cultivation conditions. Turning and sun-drying the soil several times during the dog days can eliminate large numbers of pathogenic nematodes; remove diseased plants, diseased residues and wild hosts; fertilize and water reasonably to make the plants grow vigorously. ③ Soil disinfection; steam the growing medium in a steamer for about 2 hours. ④ Hot water treatment; soak the diseased propagation parts in hot water (at 50°C, soak for 10 minutes; at 55°C, soak for 5 minutes), which can kill nematodes without injuring the host. ⑤ Chemical control; use about 25 g of 3% carbofuran granules per square meter (this pesticide is highly toxic, so safety must be paid attention to when using it), apply it evenly into the soil, cover with about 10 cm of soil, and water thoroughly; the effective period is as long as about 45 days, and it can also control various other pests at the same time.