Occurrence and control of peppermint rust

Peppermint is a well-known medicinal plant at home and abroad, the whole plant is used as medicine. It is produced in Jiangsu. In recent years, with the adjustment of the rural planting structure and the needs of the market, the planting area of peppermint in various parts of Jiangsu has been expanded, but in the process of growth and development, it is often damaged by rust, which not only seriously reduces the yield, but also affects the quality. the occurrence and control methods of peppermint rust are introduced as follows:

First, symptom characteristics: rust is a common and important disease of mint. Mainly for damage to leaves and stems. At the beginning of the disease, yellow and orange micro-raised blister spots were produced on the leaves or tender stems, and sometimes several blister spots combined into large spots and blister epidermis ruptured, spreading yellow, orange or ferruginous powder (summer spores of the pathogen). In the later stage of the disease, the disease produced black powder (the winter spores of the pathogen), the damaged leaves grew poorly at the initial stage, and the photosynthesis was seriously affected due to the attachment of yellow spores on the leaf surface. Most of the leaves dried up, resulting in early defoliation. After the disease of the tender stem, the stem above the diseased part wilted at first, and then the tender stem withered and died. Peppermint rust also harms many kinds of medicinal plants such as Panax notoginseng, Yuanhu, Atractylodes macrocephala, Angelica sinensis, Fritillaria and so on.

Second, the occurrence rule: the pathogen overwintered with winter spores on the diseased remains of the soil, and the winter spores could also adhere to the seeds for the winter. In the following year, winter spores germinate and cause damage. From late May to late June, in case of continuous overcast, rainy or dry weather, it is very easy to get sick, spread quickly and cause serious damage, and summer spores are spread by the wind. The distance of transmission is as little as a few kilometers or dozens of kilometers. Therefore, once rust occurs, it often has a wide range and large area.

III. Prevention and control methods

1. Implement crop rotation. That is, crop rotation with rust pathogen non-host crops for more than 3 years.

2. Rational fertilization. During the growth period of peppermint, the application of nitrogen fertilizer should be avoided, and the application of phosphorus and potassium fertilizer should be properly increased to promote the steady growth of plants and enhance disease resistance. At the same time, attention should be paid to field drainage to prevent stains.

3. Chemical prevention and control, according to professional households who grow in large areas, spraying 1L / L 100 Bordeaux solution before the onset of the disease has a better protective and preventive effect; spraying 1200 times of 25% fenrucine and 65% of Dysen zinc has a good effect. If the disease is serious, it can be sprayed once every 10 days for continuous prevention and treatment.