Identification and Control Methods for Common Diseases and Pests of Panax notoginseng

(1) Damping-off, also known as "rotten foot plague." The pathogen is a type of imperfect fungus among the fungi, harming seeds, seed sprouts and seedlings. Affected seeds rot into a milky white juice-like state, affected seed sprouts turn dark brown and die; affected seedlings show a dark brown ring-shaped depression at the base of the false stem (leaf stalk); seedlings bend over and die.

Control methods: ① Before sowing, disinfect the soil with carbendazim or lithospermum liquid. ② Promptly pull out diseased plants when found, spread lime powder around the diseased plants, and spray with 50% thiophanate-methyl 1000-fold solution or 50% tolclofos-methyl 1000-fold solution.

(2) Root rot, also known as "chicken droppings rot," is a type of imperfect fungus among the fungi, harming the roots; affected roots turn dark brown, gradually soften and rot into a grayish-white juice-like state, with a fishy odor.

Control methods: ① Choose well-drained plots for planting, and drain promptly during the rainy season. ② When transplanting, select robust, disease-free Panax notoginseng. ③ Promptly pull out diseased plants and disinfect the diseased holes with lime. ④ During the disease period, drench the affected area with carbendazim 100-fold solution or 50% thiophanate-methyl 1000-fold solution.

(3) Phytophthora blight, also known as "leaf-falling rot." The pathogen is a type of algae-like fungus among the fungi, mainly harming the leaves; affected leaves appear dark green and water-soaked. The disease is severe during high temperature and high humidity from June to August.

Control methods: (1) Clean the field, gather up withered branches and fallen leaves in winter, and burn them in a centralized manner. (2) Before the disease occurs, spray Bordeaux mixture 1:1:50, once every half month, for 2-3 consecutive times; after the disease occurs, spray 65% zineb 500-fold solution, or 50% thiram 1000-fold solution, or dexon 500-fold solution, once every 7 days, for 2-3 consecutive times.

(4) Anthracnose. The pathogen is a type of imperfect fungus among the fungi, harming the aboveground parts; leaf lesions are yellowish-brown with a distinct brown edge, and later small black dots form on the lesions, which easily perforate; lesions on leaf stalks and stems are yellowish-brown prismatic spots with a sunken center; lesions on fruits are round, slightly sunken brown spots. The disease is severe under high temperature and high humidity.

Control methods: ① Clean the field and promptly burn withered branches and fallen leaves. ② Select disease-free Panax notoginseng as seed stock, dip briefly in Bordeaux mixture 1:1:200 before transplanting, dry in the shade, then transplant. ③ Soak seeds in 100-150-fold 40% formalin for 10 min, rinse clean with water, dry in the shade, then sow. ④ During the disease period, spray 65% zineb 500-fold solution or 50% thiram 1000-fold solution, once every 7 days, for 2-3 consecutive times.

(5) Rust disease, locally called "yellow grease" or "yellow blister disease." The pathogen is a type of basidiomycete among the fungi, mainly harming the leaves; the affected spots on the leaves initially appear as small yellow dots protruding like needle tips, then expand into round or radial shapes with irregular edges, and after the spore masses of the pathogen rupture, yellow powder is released.

Control methods: ① In winter, prune the stems and leaves of diseased plants, and spray with 1-2 degrees Baume lime sulfur mixture. ② During the disease period, spray 200-300-fold dinitro compound or 0.3 degrees Baume lime sulfur mixture, or disodium ethylenebisdithiocarbamate 300-fold solution, once every 7 days, for 2-3 consecutive times.

(6) Powdery mildew. The pathogen is a type of imperfect fungus among the fungi, mainly harming the leaves; affected leaves are covered with grayish-white powder.

Control methods: ① In winter, clean the field and prune the leaves of diseased plants, and spray with 1-2 degrees Baume lime sulfur mixture. ② In the early stage of the disease, spray 0.3 degrees Baume lime sulfur mixture or 50% thiophanate-methyl 1000-fold solution, once every 7 days, for 2-3 consecutive times.

(7) Short-whiskered mite, also known as red spider, belongs to the family Tetranychidae, order Acariformes, class Arachnida; adults and nymphs gather on the underside of leaves to suck sap and spin silk webs. This turns the leaves yellow, and they eventually fall off. After the flower disc and red fruit are harmed, they become shrunken and dried out.

Control methods: ① In winter, clean the field, gather up withered branches and fallen leaves and burn them, and after cleaning the field, spray 1 degree Baume lime sulfur mixture. ② Starting in April, spray 0.2-0.3 degrees Baume lime sulfur mixture, or use 20% tetradifon wettable powder 1500-2000-fold solution or 25% chlordimeform aqueous solution 500-1000-fold solution for spraying, once every week, for several consecutive times.

(8) Cutworm: see the control methods for ginseng.

(9) Slug, also known as dry snail or slug, is a type of mollusk. It bites and feeds on seed sprouts, stems and leaves, causing notches. It feeds and causes damage at night and in the early morning.

Control methods: ① In winter, turn over and sun-dry the soil. ② Before planting, apply 300-375 kg of tea seed cake per hectare as base fertilizer. ③ During the occurrence period, spread lime powder on the bed surface or spray with 3% lime water to kill them.