Control techniques of main Diseases and insect pests of Perilla frutescens

Perilla Frutescens var.Crispa is a kind of 1a herbaceous plant belonging to Perilla genus of Labiatae family. It is also called Gui Ren, Su Zi, Shan Su, Chi Su, Hei Su, Bai Su and Hui Su. It is called Su in Er Ya Shi Cao. It is not only a special dish with rich nutrition, but also a traditional Chinese medicine with good curative effect. It is also a widely used industrial raw material and has a broad development prospect. However, in high-yield cultivation, some pests and diseases are often found, and the common ones are mainly the following:

I. Major diseases

1. Rust: rust is caused by monospora fungi. The pathogen mainly overwinters in the soil with the diseased body of the plant, and infects the disease in the following year. A large number of summer spores are distributed on the diseased spot, which is transmitted by airflow and rain. Generally, the disease is more serious in rainy season, and the low-lying land with poor drainage and over-dense planting and poor ventilation and light transmission are also more prone to disease. It mainly damages the leaves. At the beginning of the disease, yellow and white spots appeared on the back of the leaves from bottom to top, and then expanded to the whole plant; at the later stage, the disease spots ruptured and gave off orange or even black powder until the leaves withered and fell off, and died early. Its prevention methods:

1. Agricultural technology control: implement crop rotation and crop rotation to avoid continuous cropping: select plots with high terrain and good drainage for planting, or make high beds, pay attention to clearing ditches and draining, reduce field humidity; apply enough decomposed farm organic fertilizer, increase phosphorus and potassium fertilizer, improve disease resistance; reasonably plant closely, timely pick leaves and branches, so as to facilitate ventilation and light transmission; after harvest, timely remove the residues of diseased plants, bury them deeply or burn them, so as to avoid the retention and spread of germs.

2. Chemical control: Before sowing, dressing seeds with 15% triadimefon 0.4% by weight; spraying bordeaux mixture of 1:1:200 for 2-3 times at the initial stage of disease; or spraying 25% triadimefon solution of 2 000 times, or 15% triadimefon solution of 1 000 times, or 25% dimefon solution of 4 000 times, once every 15-20 days; Or spray 250 times solution of 97% sodium rust, 200 times solution of 50% dinitrate powder, or 400-500 times solution of 50% sulfur colloidal suspension once every 7-10 days, and spray 2-3 times continuously.

2. Spot blight: Spot blight is also caused by fungi. The bacteria overwinter mainly on the residues and seeds of diseased plants. When the temperature is 20-25℃ and the relative humidity is above 90%, it is conducive to the occurrence of disease. Continuous cropping land, low-lying land, excessive watering, poor drainage and over-dense planting plots, serious disease. The disease usually occurs in early summer until late autumn. At the beginning of the disease, brown or black small spots appear on the leaves, gradually expanding into large spots, forming holes after drying, until the leaves fall off. Its prevention methods:

1. Agricultural prevention and control: select disease-resistant improved varieties, pay attention to keeping seeds without disease plants, prevent seed transmission; pay attention to crop rotation and avoid continuous cropping; apply fully decomposed farm manure, increase phosphorus and potassium fertilizer, improve plant disease resistance; pay attention to drainage in rainy season, reduce field humidity; planting should not be too dense, timely pick leaves and branches, improve ventilation and light transmission conditions; timely remove residues of diseased plants in the field, reduce bacteria sources.

2. Chemical control: In the early stage of disease, spray 1:1:200 Bordeaux mixture, or 65% maneb 700 times solution, or 70% maneb 500 times solution, or 58% metalaxyl manganese zinc 400 times solution, or 75% chlorothalonil 500 times solution, or 50% carbendazim 500 times solution, or 50% thiophanate-methyl wettable powder 500 times solution.

3. Root rot: a fungal disease, mainly transmitted by rain, undecomposed farm manure and farm implements. In the case of high temperature and humidity, low-lying ponding, heavy soil and continuous cropping for many years, the disease is serious. Harm rhizomes, taproot damage rot, do not have lateral roots, plant short, serious stem and leaf withered death. Its prevention methods:

1. Agricultural prevention and control: rotation shall be carried out, and no continuous cropping shall be carried out for more than 3 years; the seedbed shall be fully sunned before sowing, and sufficient decomposed manure shall be applied to cultivate disease-free seedlings; deep grooves and high beds shall be dug, drainage shall be done well, and the ecological environment in the field shall be improved; the diseased plants shall be burned intensively, and the diseased places shall be disinfected with lime.

2. Chemical control: In the early stage of disease, spray 50% thiophane methyl WP 500 times solution, or 75% chlorothalonil 600 times solution, or 75% dexone 1000 times solution, or 40% polysulfide suspension 800 times solution. Mainly spray the rhizome, about once every 7 days, continuously spray 2-3 times.

Powdery mildew: commonly known as white disease, is a fungal disease, the pathogen in the field on the sick body winter, become the source of early infection in the following year. The optimum temperature for the disease is 16-24℃. The disease is serious when the plant growth is weak in alternate weather of high temperature, high humidity and high temperature and drought. Its prevention methods:

1. Agricultural prevention and control: seriously ill land shall be rotated with non-host crops for more than 2 years; high terrain and good drainage fields shall be selected for planting; decomposed livestock and poultry manure shall be applied to cultivate strong seedlings; ventilation and light transmission shall be paid attention to in the field, humidity shall be reduced; fertilizer and water management shall be strengthened to prevent excessive growth or premature senescence of plants; residues of diseased plants shall be burned to eliminate bacterial sources.

2. Chemical control: In the early stage of the disease, spray 25% triadimefon 2000 times solution, or 15% triadimefon 1000 times solution, or 40% carbendazim sulfur colloidal suspension 500 times solution, or 50% thiophane methyl colloidal suspension 500 times solution, spray once every 7-10 days, spray twice continuously; also spray baking soda 500 times solution immediately at the beginning of the disease, spray once every 3 days, continuously 4-5 times, can control the harm.

5. Cuscuta: In some high-yield fields of perilla, sometimes pieces of perilla plants can be seen entangled by many golden filaments, and the leaves become yellow and withered. This is a fully parasitic seed plant_dodder seed, which absorbs nutrients from perilla, feeds itself, damages and even kills perilla. Its prevention methods:

1. Agricultural control: pay attention to not using seeds of diseased land, carefully select seeds of perilla, or remove dodder seeds mixed in seeds of perilla before sowing to prevent dodder from mixing; manure shall be fully fermented at high temperature, and dodder seeds mixed in manure shall be rotted; control to hoe and eliminate dodder seeds before they are entangled with perilla after germination; when sporadic dodder seeds are entangled for the first time, completely remove dodder vines before flowering and setting seeds, and burn them all. To prevent future trouble.

2. Chemical control: When dodder seeds are young, cut off their stems and vines with a stick, spray "Lubao No. 1" inoculant containing no less than 30 million live spores per milliliter of water on cloudy days or in the evening; spray 0.23 kg of lasso emulsifiable concentrate or 0.4 kg of napropamide emulsifiable concentrate per mu with 100 kg of water after sowing of perilla.

II. Main pests

1. Red spider: mainly stings the leaves and tender parts of perilla, especially in the middle and late stages of perilla growth, causing serious damage, resulting in plant deformity and premature aging. Its prevention methods: