Occurrence and control of diseases and insect pests of Radix Scrophulariae

Rehmannia glutinosa is the fresh or dried root of Radix Rehmanniae. Those who dry after steaming are called "cooked Rehmannia", which is commonly known as "cooked ground", which has the functions of clearing heat and cooling blood, invigorating fluid and moistening dryness, regulating menstruation and tonifying blood, nourishing yin and tonifying kidney. Raw place, its rhizome taste is slightly sweet, with the effect of nourishing yin and clearing heat, cooling blood and hemostasis, treating fever, irritation, rash, Yin deficiency and low fever, eliminating thirst, hematemesis, white blood, urine blood, metrorrhagia, sore throat and so on. There are mainly 9 kinds of diseases and insect pests of Rehmannia glutinosa, and the control measures are as follows.

1. Rehmannia spot blight

Starting in April, the damage was serious when it was rainy from July to August, and the leaves harmed Rehmannia glutinosa with round and irregular yellowish brown spots with small black spots. Prevention and treatment: spray 1 ∶ 1 ∶ Bordeaux solution at the initial stage of the disease, spray once in 13 days, 3 times in a row, or use 60% Dysen zinc 500 times 600 times in 13 days for 3 times in a row. Burn the diseased leaves and do a good job of drainage. After August, cool night and hot day is very conducive to the occurrence of spot blight, and when the conditions are suitable, it will be a pandemic in 5-7 days, resulting in a large area of leaves curling and drying up and dying. It can be foliar sprayed with chlorhexidine or 58% remidol or 1 ∶ 1 ∶ 150 Bordeaux solution, and the control effect is better.

two。 Rehmannia glutinosa wilt

Also known as root rot, it began in May and became serious from June to July, causing damage to roots and aboveground stems. At the initial stage of the disease, the petiole showed a brown spot of water immersion, the petiole rotted, and the aboveground withered and drooped. Prevention and treatment: select high-dry land for planting; rotate with Gramineae crops for about 4 years. Set up drains. The roots of disease-free seeds were selected and the seeds were soaked with 1000 times of carbendazim. At the initial stage of the disease, 50% carbendazim was irrigated with 1000 times of carbendazim or 1000 times of carbendazim, once every 10 days for 2 times in a row. After July, 58% Redomir, 80% Dasheng M54, 58% Metalaxyl? 600 × 800 times liquid, such as manganese, zinc or 50% carbendazim, should be sprayed on leaves every 7 to 10 days, especially before and after rain. When sporadic Fusarium wilt plants appear in the field, the diseased plants and surrounding healthy plants can be irrigated with 50% carbendazim or 50% dimethazone 500 times solution plus a small amount of potassium dihydrogen phosphate, 500g per plant for 2 or 3 times in a row to prevent the spread of the disease.

3. Rehmannia virus disease

Also known as mosaic disease, it began in late April and was serious from May to June. Prevention and control: select virus-free seed propagation; virus-free stem tip propagation; control aphids, select disease-resistant varieties. After completing the seedlings, use 70% mancozeb or 58% metalaxyl? Mn-Zn or 50% carbendazim, 50% dimethazone 500 × 800 times solution plus virus A can prevent and postpone the occurrence of virus disease and Fusarium wilt.

4. Soybean cyst nematode disease

It started in May and was serious from June to October, causing damage to the roots. The main roots are damaged, the aboveground plants are poor, short, the stems and leaves are yellow, the floral organs are grouped, and the fruit is little or not fruiting. When the diseased plant was pulled out, the root system was underdeveloped, the branched root decreased, the fine root increased, the root nodule decreased significantly, and there were white particles on the root, that is, the female cyst of pathogenic nematode. Prevention and control: ① agricultural measures rotation, rotation with cereal crops for 1-2 years, application of phosphate fertilizer, timely irrigation. ② chemical control with 3% carbofuran granules, 2~4kg per mu, application in the sowing ditch, covering soil after application, or 3% methyl isosalidophos granules, 5~6kg per mu, ditch application, covering soil after application.

5. Cotton red spider

The adults and nymphs of red spiders sucked sap on the back of the leaves in May, and the injured area showed small yellow-white spots, until the leaves were brown and dry. It can be sprayed with 48% Lexben 1000 × 2000 liquid or 50% phoxim 800 × 1000 fold liquid plus high-efficiency pyrethroid 800 times, as well as 20% manling and other high-efficiency and low-toxic insecticidal and acaricidal agents, which can be sprayed twice in a row to control the occurrence of insect pests.

6. Rehmannia glutinosa leopard pattern butterfly

It started from April to May, and the larvae were harmful to the leaves. Prevention and control: clean the countryside; spray and kill with 90% trichlorfon 800 times solution in infancy.

7. Rehmannia glutinosa

Is infected by aphids and leafhoppers, so that the leaf surface into yellow-white nearly round spots, leaf veins raised, uneven, wrinkled. Control: spray and kill aphids with 80% dichlorvos 1500-2000 times.

8. Rehmannia glutinosa

The main damage leaves are round or nearly round, some are semicircular or irregular due to the limitation of leaf veins, the size of 2~12mm is light brown in the initial stage, and slightly brown or purplish brown in the middle of the later stage, with concentric rims. Black dots appear in the disease part, that is, the conidium of the pathogen. In severe cases, the diseased leaves wither and die. The pathogen overwintered in the soil with conidia and produced conidia in the following year for primary infection and re-infection. The disease occurred earlier than spot blight, generally began to occur in early May, entered the peak period in June, and gradually decreased after the middle of July. Prevention and treatment: after harvest, Rehmannia glutinosa should clean the countryside in time, and the diseased remains will be burned or buried deeply. Increase the application of phosphorus and potassium fertilizer, dredge ditches and drainage after rain, prevent moisture retention, and pay attention to dredging diseased leaves. At the initial stage of the disease, 70% mancozeb wettable powder 500 times or 75% chlorothalonil wettable powder 600 times 700 times were sprayed once every 7 to 10 days.

9. Underground pest

The main pests are ground tiger, mole cricket and golden needle worm. 100g of 80% trichlorfon wettable powder plus a small amount of water, stir-fried wheat bran or bean cake 5kg can be sprayed in the evening to trap and kill.

In the prevention and control of diseases and insect pests of Rehmannia glutinosa, it is strictly forbidden to use pesticides with high toxicity, high residue or "three causes", so as to avoid pesticide residues polluting the environment and causing harm to people.