Introduction and Control of Cowpea Rust

Cowpea (scientific name Vigna unguiculata), commonly known as carob beans, ginger beans, with beans, hanging beans. Cowpea is divided into cowpea and rice cowpea, belonging to the legume family. Cowpea is an annual plant of Leguminosae. There are three kinds of stems: dwarf, semi-vine and vine. In the south, trailing is the main cultivation, followed by dwarfism. Annual twining herb of butterfly family, leaflets 3, terminal leaflet rhomboid-ovate, 5-13 cm long and 4-7 cm wide, apex acute, base subrounded or broadly cuneate, both surfaces glabrous, lateral leaflets obliquely ovate; stipules ovate, ca. 1 cm, inserted into a short distance. Calyx campanulate, glabrous; Corolla lilac, ca. 2 cm, with yellowish whiskers in the upper part of the style. Pods linear, pendulous, up to 40 cm long. The flower and fruit period is from June to September.

Cowpea requires high temperature and strong heat tolerance, and the suitable temperature for growth is 20-25 ℃. It can bear pods normally and does not fall flowers when the temperature is above 35 ℃ in summer, but it is not resistant to frost. When the temperature is below 10 ℃, the growth is inhibited. Cowpea belongs to short-day crops, but cowpeas cultivated as vegetables are mostly medium-light, and the sunshine requirements are not very strict, such as red-billed swallow, cowpea 28-2 and other varieties, which can be cultivated in spring, summer and autumn in the south. Cowpea has a wide adaptability to the soil, as long as the drainage is good, the soil is loose, the fields can be planted, the pods are tender, and the pod stage requires sufficient fertilizer and water. Cowpea is a climbing plant, so it is necessary to build a shelf with a height of about 2 meters when the seedlings grow above 30cm. The materials are usually Reed, thin bamboo pole, thin wood and so on. The top branches of cowpea have the habit of winding and climbing, and will climb on their own.

Geographical distribution of cowpea

Native to India and Myanmar, mainly distributed in tropical, subtropical and temperate regions. Common cultivation in all parts of China. It is widely cultivated in tropical and subtropical regions of the world.

Introduction and control of cowpea rust

The disease mainly occurs in leaves and can also damage petioles and pods in severe cases. In the early stage, the leaf back produced small yellow spots, gradually browned, bulged in the shape of pustules, then expanded into a pile of summer spores, the epidermis ruptured, and scattered reddish-brown powder, namely summer spores. In the later stage, a black pile of winter spores was formed, which made the leaves deformed and fell early. Sometimes summer spores or winter spores are produced on leaf veins and seed pods. The seed pod is infected and cannot be eaten. In addition, sometimes slightly protruding chestnut brown spots can be seen on both sides of the leaf, that is, the sex organ of the pathogen; the back of the leaf produces a yellowish-white coarse velvet, that is, the rust organ.

Cowpea rust is caused by cowpea unicellular rust and cowpea unicellular rust. It is a single host parasitic rust fungus, which can produce sex spores, rust spores, summer spores, teliospores and basidiospores. It is an idiopathic parasite, only harmful to cowpea. In the north of China, winter spores are mainly used to overwinter on diseased remains. The average daily temperature of the next spring was 21 Mel / 28 ℃, with water-wet and scattered light conditions. The teliospores germinated for 5 days to produce basidiospores, which were transmitted by airflow to produce bud tubes, invade cowpea leaves and produce sexual spores and rust spores at the same time. After the rust spores mature, they germinate and invade on the cowpea leaves, and then form a pile of summer spores and produce summer spores. After the summer spores matured, they spread by airflow and repeated infection for many times. it was not until after autumn, or when the conditions in the later stage of plant growth were not suitable, that winter spores were formed and winter spores were produced. However, the southern pathogens mainly overwintered and oversummer with summer spores. The average daily temperature is 23 ℃, the relative humidity is 90%, and the incubation period is 8 Murray 9 days. Under the condition that the daily average temperature is stable at 24 ℃ and continuous rain, it is easy to be popular.

Prevention and control of cowpea rust:

In the early stage of ①, 15% triadimefon wettable powder 1000Mel 1500 times, or 40% Fuxing EC 8000 times, or 50% verapamil EC 800x, or 50% sulfur suspension 200x, or 30% solid stone sulfur mixture 3000 times, or 65% Diesen zinc wettable powder 500x, or 50% carbendazim wettable powder 800Fil 1000 times were sprayed. Or 4000 times of 25% enemy demulsifiable oil and 2000 times of 15% triadimefon wettable powder, every 10--15d1 for 3 times in a row.

② should not be watered before the rain, and cowpeas should not be cultivated in succession in spring and autumn.