Occurrence and Integrated Control techniques of garlic Heart Rot

In recent years, the garlic industry in Pizhou has developed rapidly, and the planting area has grown from 3333 hectares in the 1970s to 33000 hectares in 2004. it has become the largest garlic producing area and the national standardized high quality garlic production demonstration county (city). However, with the expansion of garlic cultivation area and the extension of continuous cropping years, the occurrence of various diseases and insect pests is becoming more and more serious, especially the damage of garlic heart rot is increasing year by year, which seriously affects the yield and quality of garlic.

1 occurrence regularity and harmful symptoms

The occurrence regularity of ① was sporadically found in Chefu Mountain and Suyangshan Town in late February 2002, and expanded to 5 towns in 2003, with an area of 1667 hectares in 2003 and 5333 hectares in 2004. Garlic-growing villages and towns all occurred in varying degrees. Generally, after planting garlic, the disease began to get sick in late February of the following year, the incidence peak in mid-late March, the peak of the disease in early April, individual fields in November before the beginning of the disease, if not timely control, the whole plant will die.

The symptoms of ② were preliminarily identified as bacterial diseases. After being infected by the disease, garlic showed physiologically dysfunctional growth, the leaf tip turned dark brown inward, the whole plant shrunk and did not extend upward, the growth point (base) softened and rotted, and the base expanded and soft, rotting from the inside to the outside, giving off a fishy stench.

2 Analysis of the causes of the disease

The sufficient bacterial source of ① is the basic condition for the disease to rise from sporadic disease to major disease in only 3 years, indicating that the field bacterial source is sufficient, especially in the whole growing period of garlic in 2003, Rain Water is sufficient, the temperature and humidity in the field is conducive to the occurrence of the disease, the garlic market is in the doldrums all the way, garlic farmers naturally do not control it, the accumulation of bacteria in the field, coupled with the bacteria carried by garlic itself, the disease became more serious in 2004.

Climatic factors such as precipitation of ② were the main cause of the disease. It was observed that the pathogen could grow at 4: 39 ℃, and the main cause was humidity. It was rainy from late February to early March. After two or three consecutive days of heavy rain, the temperature recovered on a sunny day, and the field began to see the disease and spread rapidly. Within a week, the rate of diseased field and diseased plant increased by 8% and 1.9% respectively. In addition, the irrigation diseases were aggravated after the year. According to the investigation on March 20, 2004, there was a great difference between irrigation and non-irrigation diseases in similar fields.

③ analysis of other factors from the investigation results, partial application of nitrogen fertilizer or excessive application of organic fertilizer, the disease is serious; in garlic varieties, the disease of white garlic is more serious than that of red garlic; early-stubble garlic is more serious than late-stubble garlic; unsoaked garlic is heavier than seed-soaking garlic.

3 integrated prevention and control technology

3.1 Agricultural control

① rejuvenation and cultivation of strong seedlings of garlic is easy to degenerate, and the areas with great geographical differences and cultivation conditions will be selected after 2 to 3 years, and the injured, rotten, soft, non-bud and diseased cloves should be removed when selecting garlic species, and large garlic and garlic cloves should be selected as seeds to cultivate strong seedlings and improve disease resistance.

② cultivation measures: high border and deep ditch to ensure smooth field drainage in flood season. Sowing seeds at the right time, applying more rotten organic fertilizer and increasing phosphorus and potassium fertilizer. High-quality rotten soil fertilizer 3000~4000kg was applied as base fertilizer every 667m2.

3.2 Pesticide control

① garlic seed disinfection: garlic detoxification king 80ml soaked 200kg garlic seeds in water for about 6 hours, then sowed them for 2 hours and then sowed seeds. During sowing, 3~4kg garlic heavy stubble agent mixed with fine soil 30kg was applied every 667m2, and soil sterilization treatment was carried out.

② field spray garlic after the initial stage of the disease, first pull out the diseased plants, every 667m2 with 20% Longke bacteria (thiobacillus copper suspension) 60g 40~60kg spray on the water. Continuous prevention and treatment for 2 or 3 times. In case of rain after medication, spray immediately after the rain, should be sprayed up and down evenly, the control effect is good.