Introduction to a new method for disease prevention and rot control: effective tricks for crop disease prevention and control

Introducing a new method for disease prevention and rot control: Introducing a new method for disease prevention and rot control: the role of hydrogen peroxide (commonly known as hydrogen peroxide solution; molecular formula: H2O2; molecular weight: 34.016) in the prevention and treatment of orchid stem rot and soft rot. Since the beginning of spring this year, with the arrival of hot summer weather, many orchid growers have not been panicked by the appearance of BLS, but have been driven to distraction by soft rot and stem rot. Some orchid growers have paid a heavy price for this, and I myself have also suffered severe losses! The reasons are as follows: 1. Neglecting sterilization and disinfection of the orchid growing area and planting pots. Some orchid growers only realize they need to sterilize and disinfect when soft rot and stem rot occur and they feel heartbroken. Of course, it is better late than never, but by then it is already too late. The new shoots they had looked forward to with such difficulty are sometimes impossible to protect, and are gone overnight, which means the results obtained that year are also gone; 2. Careless and extensive management. Fertilizer and water spraying and pesticide application are done indiscriminately, and water injury and pesticide injury create conditions for pathogen infection. In some cases, soft rot in new shoots is discovered a little late (2-3 days), affecting the mother plant, causing black rot at the base of the outer leaves of the mother plant, premature leaf loss, and even plant collapse; 3. Lack of experience. Many cases of soft rot and stem rot mostly occur in deeply planted half-year-old plants and small seedlings. Half-year-old plants and small seedlings are tender, and because new buds emerge from the roots, the new buds and small seedlings have too large a water-exposed surface area. The more prized the variety, the more unavoidable it is for water to accumulate in the bracts. If the planting medium cannot be opened in time for ventilation, soft rot and stem rot result. 4. Negligence and delayed treatment. People often look at new shoots growing from deep positions and see that they are very strong, assuming there will probably be no problem, but in the end there is a problem. Some also use fertilizer that has not been fully decomposed, causing the soil temperature to rise, scalding the new shoots and causing infection; It can be said that soft rot has left orchid growers trembling with fear and at a loss what to do. As everyone knows, soft rot is caused by Erwinia bacteria (bacterial in nature). The optimal temperature range for the growth and reproduction of this bacterium is between 25-40°C, with moist soil and a pH of 3.5-6. When the pH of the planting medium is above 7, or at an environmental temperature of 50°C for 10 minutes, it is killed; generally, soft rot occurring in new shoots and stem rot in old plants accompany each other. Stem rot is also very troublesome. Stem rot pathogens are caused by Pythium and Fusarium. Pythium develops fastest under high temperature and excessive moisture, while Fusarium develops fastest under high temperature and dry conditions. The former manifests as blackening from the bottom to the top at the leaf base, with reverse seepage of water leading to death; the latter manifests as yellowing at the leaf base, drying and dehydration, with yellow leaves breaking at a touch and premature leaf loss. Soft rot and stem rot share a common early warning sign. According to my observations over many years, during normal management, when the surface of other orchid pots has dried, the surface of an infected orchid pot does not dry for 2-3 days, or even 3-4 days. This is a symptom of declining water absorption and transport function of the orchid roots and pseudobulbs, and measures must be taken promptly to prevent spread. In the process of preventing and treating soft rot and stem rot, this year I tried a new method, which is using hydrogen peroxide (commonly known as hydrogen peroxide solution). This product is a colorless transparent liquid. It is non-toxic, has a certain corrosive effect on the skin, and is a strong oxidizing sterilizing and disinfecting agent. Concentrations above 25% are explosive dangerous goods and are controlled commodities. 3% hydrogen peroxide is sold in ordinary pharmacies. This is the concentration used to treat soft rot and stem rot in orchid seedlings. For preventive use, it can be diluted with double the amount of water. Specific operation: because the Erwinia bacteria that cause soft rot depend on moisture to survive and generally gather around the pseudobulbs, there is no need to remove the plant from the pot. A syringe can be used to draw 50 ml and inject it at the affected site and around the adjacent pseudobulbs. If blackening or yellowing is found at the leaf base of adjacent pseudobulbs, use a needle to pry it open and inject a small amount of hydrogen peroxide solution, once a day for 2 consecutive times. After each time, wait 30 minutes and then thoroughly drench the roots with clean water once. After the second clean water drench, place in a ventilated area for shade cultivation for one week. Do not water within one week. This can control the development of the disease. During the orchid growing period, it is beneficial to persist in alternating use of 1/1000 potassium permanganate and 1/100 hydrogen peroxide solution to sterilize and disinfect the orchid growing area and orchid seedlings. A 500 ml bottle of hydrogen peroxide costs about 10 yuan. I bought 30% hydrogen peroxide from a specialty store, and 500 ml costs about 90 yuan. I prepared a 1-3/100 solution myself for use. Safety reminder for high-concentration hydrogen peroxide: keep sealed. Store in a cool place, and avoid vigorous shaking. High-concentration hydrogen peroxide is corrosive to the skin, so be careful not to get it on your hands. Low concentrations are less corrosive, and if it gets on your hands, it can be washed off promptly with water. I hope orchid growers will give it a try. It has no side effects and is much safer than copper sulfate, lime water, or agricultural streptomycin sulfate! Let soft rot and stem rot no longer perplex us, and let new shoots grow strong and healthy with abundant and bountiful harvests!