Causes and control methods of rot disease of lotus root, lettuce and lettuce!

Lotus root, lettuce and lettuce are prone to rot in the production process, so what is the cause of them? What are the prevention and control methods? Let's take a look at it.

I. the causes and control methods of lotus root rot.

Cause of occurrence:

1. It is a fungal disease, which mainly affects the underground stem of lotus root, causing browning and rot, and causing aboveground wilt.

two。 The symptoms of underground stem damage were not obvious in the early stage, irregular brown spots appeared in diseased stem, lotus whip and root in the later stage, dissection of diseased stem and vascular bundle browning in the center.

3. The color of the leaves of the damaged plants became light, and then water-stained wilting appeared on the edge of the leaves, resulting in the curl and death of the whole leaf. The pathogen overwintered with mycelium in lotus root or soil, and the seed lotus root and field with bacteria were the main sources of primary infection of the disease.

Prevention and control methods:

1. In the old lotus root area, in order to deal with the residual plants in time, in addition to leaving the lotus root fields, the residual stalks should be cut down and burned in time after harvest; the harvested lotus root fields can be planted in winter, and the fields that do not plant overwintering crops and fields without water should be deeply turned to dry in winter. The field can be irrigated and soaked in winter when the water source is good, and it is difficult for bacteria to survive the winter in the paddy field.

two。 Lime treatment, before the first ploughing, 100,150kg quicklime and 25kg 30kg lime nitrogen per mu were evenly spread, and then turned deeply into the soil, which can not only play the role of fertilization, but also play the role of adjusting soil pH and disinfection, and effectively kill a variety of pathogenic bacteria.

3. Choosing to stay in the field without disease can avoid planting lotus root with bacteria and reduce the source of primary infection.

4. After the seed lotus root is dug up, soak the seed lotus root with 33.5% quinoline copper 1000 times solution plus 70% methyl topiramate wettable powder for about 10 hours, fish out and dry before planting; the above agents can also be used to cover the seed lotus root film after spraying, sealing and disinfecting for 24 hours, and planting after drying.

5. Rotation, water-dry rotation every other year as a good, generally continuous cropping for no more than 3 years. Paddy-upland rotation can purify soil, reduce disease accumulation, regulate soil nutrients, improve soil structure and improve disease resistance.

6. Apply enough rotten organic fertilizer and topdressing at the right time. Topdressing requires the combined application of nitrogen, phosphorus and potassium fertilizer, as well as trace fertilizers such as molybdenum fertilizer, zinc fertilizer and boron fertilizer.

7. In the early stage of the disease, pull out the diseased plant in time, mix 50g of fine soil with 500g of carbendazim + 75% chlorothalonil wettable powder per mu, mix well, pile and sprinkle in the shallow lotus root field for 3 hours, and at the same time apply 1000 times liquid foliar spray with 50%, once every 7 days and 3 times in a row. The lotus root field can also be drained in the middle of June, and the soil around the lotus tree can be irrigated with 600-fold liquid of Dixong, and then rewatered the next day, once every 5-7 days, and sprayed 4 times in a row.

2. causes and control methods of rotting disease of lettuce

Cause of occurrence:

1. The pathogen overwintered on the diseased body or in the seed, and invaded from the stomata or leaf edge water pores and wounds of the seedling leaves the following year, and formed systematic infection after bacterial invasion.

two。 Long-distance transmission mainly depends on seeds and spreads in the field by means of Rain Water, insects and fertilizers. It is easy to occur under the conditions of high temperature and humidity, and the disease is serious in the land with low-lying terrain, continuous cropping and pests.

Prevention and control methods:

1. Rotation with onions, garlic and Gramineae crops for more than 2-3 years.

two。 Compost made by retting with Japanese enzyme bacteria. Select disease-free seeds, drain water in time after rain, and pay attention to the control of underground pests.

3. The initial stage of the disease began to spray 30% copper oxychloride suspension 800x solution or 30% Ludabao suspension 300x 400x solution or 50% copper succinate (DT) wettable powder 500x solution, 70%? Ethyl phosphine aluminum (DTM) wettable powder 500x liquid, 25% thiufumazole wettable powder 500ml 1000x liquid, 72% agricultural streptomycin sulfate 3500 Mel 4000 times liquid, 47% plus Renong wettable powder 1000 times liquid, 667m2 sprayed 50 liters of good solution, once or twice every 10 days. Stop using medicine 3 days before harvest.

3. Causes and control methods of lettuce rot.

Cause of occurrence:

1. The pathogen overwintered on the diseased body or in the seed, and invaded from the stomata or leaf edge water pores and wounds of the seedling leaves the following year, and formed systematic infection after bacterial invasion.

two。 Long-distance transmission mainly depends on seeds and spreads in the field by means of Rain Water, insects and fertilizers. It is easy to occur under the conditions of high temperature and humidity, and the disease is serious in the land with low-lying terrain, continuous cropping and pests.

Prevention and control methods:

1. Rotation with onions, garlic and Gramineae crops for more than 2-3 years.

two。 Compost made by retting with Japanese enzyme bacteria. Select disease-free seeds, drain water in time after rain, and pay attention to the control of underground pests.

3. In the early stage of the disease, 27% copper noble suspension 600x solution or 30% Ludabao suspension 300g 400x solution or 50% DT wettable powder 500x solution, 70% ethylphosphine aluminum (DTM) wettable powder 500x solution, 25% thioprozole wettable powder 500x 1000x solution, 72% agricultural streptomycin sulfate 3500 × 4000 fold solution, 47% Ruinong wettable powder 1000 times, 667 square meters were sprayed with 50 liters of good medicine. Once every 10 days or so, prevent and cure once or twice. Stop using medicine 3 days before harvest.