Anthracnose of Panax notoginseng (Panax notoginseng)

Symptoms can occur in both seedling stage and adult stage, and the disease in seedling stage can cause sudden collapse or top withering. The disease in the adult stage is mainly harmful to leaves, petioles, stems, flowers and fruits. Leaves infected with primary round or nearly round yellow-brown disease spots, obvious reddish brown edge, easy to rupture and perforation in the later stage. The petiole and stem are infected with fusiform yellow-brown sunken spots, causing the petiole to bend or the stem to twist. Damage to the stem base causes adult plant lodging or rhizome rot. The phenomenon of dried flower seeds appeared when pedicel and disk were infected. The fruit is also infected with nearly round yellow sunken spots, causing the fruit to turn brown and rot.

The pathogen Colletotrich μ mg10eosporioidesPenz. And C. dematium (Pers.) Grove are called Colletotrichum gloeosporioides and Colletotrichum nigricum, both of which belong to the subphylum fungus. C.g10eosporioides on PDA is initially white, then grayish white, aerial hyphae light gray; myxospores are light red after initial white; bristles are numerous; conidiophores are branched; sporogenic cells are bottle pedicel-shaped, sporulation is bottle-shaped; conidia are colorless, sickle-shaped, tip sharp, end obtusely round, 1923 × 2.5tel 4.0 (μ m). The appressorium is rich, dark brown, oval, round or clavate, and the margin is mostly regular. C. dematium see Ophiopogon anthracnose.

The pathogen overwintered by hyphae in the cortex of seed soft fruit or attached to the surface of red seed, and the residual stump or withered leaf of sheep's intestinal head was also the main place of overwintering of the disease. The disease is mainly transmitted by Hongzi, which causes the above symptoms. Hongzi infected with bacteria became the source of infection at the beginning of the following year. In the field, the pathogen mainly occurs in the rainy season, generally high temperature, high humidity from June to July, the disease spreads rapidly, continuous rain, muggy weather after rain, planting too dense easy to induce the epidemic of the disease.

Prevention and control methods (1) clean the countryside in winter and burn the sick and disabled bodies in time. (2) adopt the technology of formula fertilization, apply sufficient rotten organic fertilizer and increase the application of phosphorus and potassium fertilizer to improve disease resistance. (3) seed (red seed) treatment. Soak the red seed in 43% formalin 150 times solution for 10 minutes, remove the soft pericarp, and mix the seeds with 0.5%-1.5% 75% methyl topiramate or 70% methyl thiophanate wettable powder. The seeds can also be soaked for 2 hours after mixing 75% methyl topiramate 400x solution and 45% Dysen zinc wettable powder at 1:1 for excellent control effect. (4) the cultivation method of shelter from rain is advocated. In the rainy season, plastic film was used to cover the top of the shade shed to prevent Rain Water from drenching the plants, and the incidence rate was significantly reduced. (5) adjust and repair the ceiling or use the sunshade net to control the light transmittance. The transmittance of the shade shed in the seedling stage of Panax notoginseng should be adjusted to 17%-25%, 20%-35% in 2-4 years old, and slightly higher in early spring or late autumn every year. (6) spray 45% Dysen zinc wettable powder 400x or 1000 methyl topiramate wettable powder 1000 times, carbendazim 800m 1000 times, carbendazim 500x, 25% carbendazim EC 900x in time during seedling emergence or before rain.