Occurrence and Control of Common Diseases in the Middle and late growth period of Salvia miltiorrhiza

I. epidemic disease

1. Symptoms and etiology

In the early stage of the disease, the lower leaves of the aboveground plants turned yellow, and the top leaves lost water and drooped at high temperature at noon, which could still recover sooner or later; in the later stage, the leaf droop of the whole plant did not recover and began to rot from the base. Pull out the underground part of Salvia miltiorrhiza rhizome, you can see that the main root epidermis is water-stained, turning into light yellow, peeling off the epidermis, you can see that the pulp is completely rotten, the color of the rotten pith remains the same, slightly smelly, showing wet rot. The disease spread rapidly and generally infected plants died within 2 weeks. When the soil moisture is high, it occurs soon after Salvia miltiorrhiza seedlings are planted, and spreads rapidly, and the roots can intermittently produce white mildew, the mycelium or fruiting body of pathogenic bacteria. The pathogen was caused by Phytophthora cactorum (Leb.et cohn) Schroet. Phytophthora is referred to as Phytophthora, belonging to the subphylum flagellate fungi. Through irrigation water and Rain Water spread to the sprouts of Salvia miltiorrhiza, under the condition of high temperature and humidity, the disease spot appeared for 3 days, and spread by wind and rain. The severity of the disease is directly related to the arrival of the rainy season, the temperature and the rainfall. With high temperature in early spring, more Rain Water and frequent flood irrigation, the disease is serious and widespread.

2. Prevention and control methods

(1) crop rotation has been implemented for more than 3 years. Repeated cropping in plots with a history of disease is strictly prohibited.

(2) after the soil is selected, winter ploughing and drying should be carried out in winter. It is best to apply compost made by enzyme bacteria retting, increase phosphorus and potassium fertilizer, and control nitrogen fertilizer.

(3) High border cultivation and plastic film mulching can effectively reduce the chance of pathogen infection.

(4) after heavy rain or watering, spray medicine in time to prevent, can also spread quicklime disinfection.

(5) treatment and prevention of spread after the discovery of diseased plants.

A, 72% urea manganese zinc (Kekangling) wettable powder 800 times liquid spray.

B, 72% DuPont Krou or 72% g frost cyanide wettable powder 1000 times liquid spray.

C, 18% metalaxamide manganese zinc wettable powder 600 times liquid.

D, 70% ethyl manganese zinc wettable powder 500 times liquid.

Any of the above-mentioned drugs should be mixed according to the requirements, 50 kg per mu, sprayed once every 7 days, and sprayed 3 times alternately. Pay attention to spray evenly, so that do not re-spray, do not leak.

Sclerotinia sclerotiorum

1. Symptoms

The stem base, root bud and rhizome area of the diseased plant gradually rotted, showing dark brown, and the plant withered and died. The sclerotia with black mouse feces and white mycelia were distributed in the disease site, inside the stem base and on the surrounding soil.

2. Prevention and control methods

The main results are as follows: (1) maintain the content of water in the soil, control the excessive moisture in the soil, and plough and loosen the soil in time.

(2) during the onset of the disease, 50% ammonium chloride 0.5 kg plus quicklime 10 kg was mixed into a germicidal agent and sprinkled on the base of the diseased plant and the soil near it.

(3) irrigate the base of the diseased plant and the soil near it with 1000 times of 50% Sukeling.

Root rot of Salvia miltiorrhiza

1. Symptoms

At the initial stage of the disease, individual branched roots or whisker roots turned brown and rotted, and then gradually spread to the main root, the bark turned black and the whole root rotted. The individual stems and branches of the aboveground plant withered at first, and finally the whole plant died. The disease mostly occurs from May to November.

2. Prevention and control methods

(1) pay attention to the selection of reproductive materials for seed use. In recent years, artificial cultivation of Salvia miltiorrhiza mainly chooses the combination of sexual reproduction and asexual cultivation (that is, raising seedlings and transplanting with seeds) to carry out the production of Salvia miltiorrhiza, which effectively solves the problem of root disease of traditional pure asexual reproduction and is the basis for the prevention and treatment of root rot of Salvia miltiorrhiza.

(2) the seedlings were disinfected before cultivation. Soak the seeds with 50% methyl topiramate for 6 hours or 5% plant ash solution for 2 hours.

(3) strict selection of soil and topography. Choose plots with high terrain and good drainage for planting. The soil must be medium loam or loam to ensure good filtration and air permeability; it is preferable to have a slope of 10-15 degrees. If the terrain is flat, a deep and dense seepage ditch should be dug.

(4) in case of continuous rainy weather and moist soil, as long as ploughing in the field can be carried out, various forms of ploughing and loosening the soil should be carried out for many times, so as to break the soil lamination, remove harmful gases from the soil, and enter the fresh oxygen in the air. increase the gas exchange between soil and air, this measure can effectively prevent and reduce the occurrence of root rot of Salvia miltiorrhiza. And timely spraying fungicides to prevent.

(5) at the initial stage of the disease, the diseased plant and its surroundings were irrigated with 50% topiramate 800ml 1000 times solution.

IV. Leaf spot

1. Symptoms

Leaf spot is a kind of bacterial disease, which mainly harms leaves. There are nearly round or irregular dark brown spots on the top of Salvia miltiorrhiza leaves, which expand and converge in severe cases, resulting in leaf death. It began to occur in May and lasted until the end of autumn, and the disease was serious from June to July.

2. Prevention and control methods

(1) strengthen management and implement crop rotation.

(2) increase the application of phosphorus and potassium fertilizer, or spray 0.3% potassium dihydrogen phosphate foliar fertilizer to improve the disease resistance of the plant.

(3) at the initial stage of the disease, 50% carbendazim 500 murine 1000 times or methyl topiramate 800 times were sprayed once every 7 days for 3 times in a row.

Root knot nematode disease

1. Symptoms

Root-knot nematode disease is a parasitic disease. There are many nodules growing in the roots, which make the plant short, develop slowly, the leaves turn green, turn yellow gradually, and finally the whole plant dies. Pull up the diseased plant, there are many gall-like tumors on the whisker root, pick it out with a needle, the white dot can be seen with the naked eye, this small spot is the female nematode. Generally speaking, Salvia miltiorrhiza is easy to occur in the soil with large sand and good air permeability.

2. Prevention and control methods

(1) try not to repeat cropping, the former crop is the crop rotation of Gramineae.

(2) during soil preparation, 5 kg of 3% methyl isosphos was applied per mu and mixed into the soil.

(3) 80% dibromochlorobenzane 2ml 3 kg plus 100 liters of water, ditched and applied to the soil 15 days before planting, and covered with soil to prevent the volatilization of the solution and improve the control effect.