What about the fire dragon yangzi of soybeans?

Soybean cyst nematode disease

Soybean cyst nematode disease, also known as Verticillium wilt, yellow dwarf disease, root nematode disease, farmers called "Huolong Yangzi". It is reported that more than 22.5 million mu of soybeans in 14 provinces, municipalities and autonomous regions have been infected with the disease. Soybean cyst nematode disease harms the root system of soybean, resulting in poor growth and development of the aboveground part of the plant, shortening and dwarfing of internodes, yellowing and podding of leaves, reduced yield, generally reduced yield by 10% Mur30%, and almost no yield in serious plots. After parasitic nematode in soybean, the main root and lateral root are underdeveloped, the along root increases, the whole root system becomes hairy straight root, the root nodule is few or no nodulation, and the root is covered with white or yellow flower needle-sized protuberances. 0.5 mm in diameter, that is, the cyst of the nematode.

Soybean cyst nematode disease is transmitted by soil, water, birds and wind. Viable eggs in soil can survive for 9 years without parasitic plants and 22 months on seeds. These eggs can also survive and multiply on weeds and other crops (such as kidney beans, clover, white feather beans, wild peas, etc.). 48 hours after sowing and rooting of soybean, the cyst nematode can invade the edge of the middle pillar of the root, insert the head into the pillar, and begin to feed, and then molt three times to become an adult, when the female adult expands into a cyst and breaks through the root bark to expose the root. while the head is still inserted in the same place, the male adult leaves the root and enters the soil to look for female mating. In our province, white cysts began to be seen in mid-June, and the second generation was completed by the end of June; the third generation was completed at the end of July and early August; and another generation was completed in the first ten days of September, which could reproduce 4 generations per year, and one generation lasted 3444 days, with a minimum of 19 days. The cysts fell off in the soil along with the distribution of the root system, and the most were in the 20cm plough layer, accounting for about 90%.

The symptom of seedling disease is that cotyledons and true leaves turn yellow and grow slowly, and most nematodes absorb juice on bean roots, which seriously affect the growth and development of seedlings. In the authoritative plant stage, the plant is short, the auspicious piece yellowes gradually from bottom to top, grows slowly, blossoms late, pods less, bean chaff, and in severe cases, flowering dies three times. Another characteristic of the disease is that the root system is underdeveloped, the lateral root is less, the along root is more, the root nodule is small and few, and there are many small white or yellow-white particles on the along root.

At present, the main measures to control soybean cyst nematode are as follows:

The main results are as follows: 1. Rational rotation of soybean and non-parasitic plants such as corn and small grain crops to reduce or avoid soybean continuous cropping.

2. the effect of increasing the application of manure is the best. Starting with nutrition, Heilongjiang Institute of Agricultural Modernization has developed soybean continuous cropping agent and soybean Verticillium wilt leaf spray after many years of experiment and demonstration. The yield-preserving agent 1.5kg per mu was applied as base fertilizer during sowing, the yield per mu was increased by 22.5kg, the yield was increased by 22.1%, and the yield was increased by 13.6% by spraying Verticillium wilt leaf spray at the seedling flowering stage.

3. Chemical and biological control. The results showed that 3% carbofuran had the best control effect, and the control effect was more than 90%. The effects of ethyl thiocarbophos and 391 were also available, and planting hemp, vegetation and other non-parasitic plants in the following year after soybean harvest could alleviate the damage of cyst nematode.

4. Resistant varieties. The selection of line-resistant varieties is an important measure to increase the yield of continuous cropping soybean. The resistant line varieties No. 1 and 2 of the Institute of Saline-Alkali soil of the Provincial Academy of Agricultural Sciences, Nenjiang Institute and the Provincial Academy of Agricultural Reclamation Sciences were selected for planting.

Physiological disease

The so-called physiological disease refers to the disease caused by the lack of nutrition and the deterioration of ecological environment of soybean. For example, due to element deficiency, soybean lacks a large number of nutrients, such as potassium, nitrogen, zinc, boron, molybdenum, manganese and other diseases such as white seedling disease, flowering infertility and other diseases. at the same time, due to the hindrance of plant growth and weak growth, the whole plant shows morbid growth. it is easy to be infected with root rot, cyst nematode and other diseases. It is suggested that farmers should choose soybean continuous cropping agent and soybean Verticillium wilt leaf spray. The effect is good, the cost is low and the economic benefit is obvious. at present, it is suggested to adopt comprehensive measures to prevent and control the damage of soybean Huolong seedlings, spraying Verticillium wilt leaf spray once every 7 seconds and 10 days, and spraying 2rel 3 times in the whole growth period.