Causes and Control measures of Tomato Fusarium Wilt

Causes and Control measures of Tomato Fusarium Wilt

Around the Spring Festival in 2017, many vegetable growers asked for help at plant protection stations, and patches of tomatoes wilted in the greenhouse. After on-the-spot observation and diagnosis by technicians, the vascular bundles in the roots turned brown and necrotic from the pulled stems, and it was determined that it was caused by tomato wilt. Immediately, the technicians carried out on-site training and technical guidance, explained the causes of the disease and provided prevention and control measures.

1 harmful symptoms

Tomato wilt, also known as wilt, is a difficult to control soil-borne disease, often complicated with bacterial wilt, often in the flowering and fruiting period, not easy to find at first, withered and died in the full fruit period. The middle and lower leaves spread upward and could recover sooner or later, and then the wilting symptoms were gradually aggravated, sometimes one leaf turned yellow and the other was normal green. When the disease was serious, the whole leaf withered and died, but did not fall off. The diseased leaves are yellowish brown and pink mildew is produced on the stem against the ground when it is wet. The vascular bundles of the open stem were yellowish brown and there was no milky mucus outflow, which was different from bacterial wilt. Especially when tomatoes have 2 ~ 3 ears, there is a large demand for water and fertilizer. After the vascular bundle is blocked, water and fertilizer can not be supplied in time, so the disease is serious.

2 causes of the disease

There are many causes of the disease, especially the heaviest continuous cropping land, heavy clay and acid soil, more Fusarium wilt bacteria accumulated in the soil, excessive application of nitrogen fertilizer and deficiency of phosphorus and potassium. There are a certain amount of nematodes and other underground pests in the soil, and the germs invade the roots from the wounds damaged by the pests. In addition, soil, including raw dung and crops such as cotton, can spread germs, and Fusarium wilt can survive in the soil for many years or through infected seeds.

Most tomatoes in the greenhouse vegetable planting area of Shahe City were planted in autumn (9 ~ 10 parts). The temperature in the greenhouse was the most suitable temperature for Fusarium wilt pathogen activity (20 ℃ ~ 30 ℃). At this time, the pathogen invaded from the root wound and propagated slowly in the vascular bundle, blocking the vascular bundle, resulting in hindrance of plant water and fertilizer absorption, infection with Fusarium wilt, and tomato leaf wilt or death.

3Prevention and treatment of Fusarium wilt

3.1 Biological control

3.1.1 main points of prevention and control. According to the "soil dry humidity and plant size" to determine the amount of irrigation, in order to "thoroughly irrigate the rooting range of crops" as the purpose, generally, each irrigation professional germicidal pesticide 100 ~ 400 ml.

3.1.2 Prevention programme. The roots were irrigated with 50 ml of Qingku Rike and 15 kg of water, once in 7 ~ 10 days and 2 ~ 3 times in succession.

3.1.3 treatment regimen. First, it was sprayed or irrigated to the root, and then sprayed twice in 5 days. The therapeutic effect was better.

3.2 Agricultural control

3.2.1 Clean the shed. After harvest, remove weeds in the field and around, concentrate on burning or retting fertilizer; turn the ground deeply to destroy stubble and dry the soil, promote the decomposition of the disease and the residual body, reduce the source of disease and insect; do not remove the film, turn the ground up in the summer high temperature, block the tuyere for 15 days, high temperature stuffy shed, kill most bacteria.

3.2.2 soil disinfection. Before planting, select disease-resistant varieties, disease-free, coated seeds, if not coated, the seeds should be sterilized with seed dressing agent or seed soaking agent. Banning unripe manure and applying compost made by enzyme bacteria or rotten organic fertilizer to promote the healthy growth of crops and improve their disease resistance. Most of the soil germs gather in the fields with serious underground pests and apply sterilized and insecticidal soil before sowing or ditch. When planting, it is necessary to use more than 200 million biological agents per gram in the tomato hole. Seedling transplanting, covering with medicine and soil after sowing, and spraying insecticide and fungicide before transplanting is the key to disease prevention.

3.2.3 grafting to prevent disease. Using wild eggplant, poisonous eggplant or red eggplant as rootstock, cultivated eggplant as scion, split grafting can be highly resistant to Fusarium wilt.

3.3 timely medication for prevention and treatment. Timely prevention and control of pests after planting, reduce plant wounds, reduce pathogen transmission; timely removal of diseased leaves and diseased plants, and take out of the field to burn, disease point application or quicklime.

Fusarium wilt is easy to prevent and difficult to cure, reminding vegetable growers to give priority to prevention, combine prevention and control, eradicate diseased plants in time and sterilize the original hole; when watering, healthy plots and diseased plots are irrigated separately; when pouring medicine, the whole crop root should be fully irrigated.