How to control anthracnose of ginger with black spots and drooping leaves

Ginger anthracnose harms leaves, leaf sheaths and stems. Most of the infected leaves appear near round or irregular wet chlorosis spots from the leaf tip or leaf edge, which connect with each other into large irregular spots. In severe cases, the leaves dry up, and when wet, slightly rough small black grains grow on the diseased spots, and in severe cases, ginger leaves droop, but still remain green.

Ginger anthracnose

Pathogen: the pathogen of ginger anthracnose is Alternaria capsici, a fungus belonging to a half-known fungus. The conidium disk is formed under the host epidermis, and then breaks through the epidermis, showing a disk shape, with long dark brown setae on the conidium disk, with 2-4 diaphragms; conidia meniscus, colorless, unicellular, 20-31 × 3-6 microns in size. The black spots seen in the disease department are the asexual conidia disk and conidia of the pathogen.

Occurrence regularity: the pathogen overwintered in the ginger species in the form of hyphae or conidia disk or overwintered in the soil with the disease residue. Sowing infected ginger seeds can cause the disease of ginger seedlings. After overwintering, the hyphae are spread by wind and rain splash, insects or water. When the conditions are suitable, bud tubes grow and invade from the wounds of the ginger epidermis. After the initial invasion, a large number of conidia grew, and after transmission, they were frequently re-infected.

Disease conditions: high temperature and humidity are beneficial to the occurrence of ginger anthracnose. If the average temperature is 26-28 ℃ and the relative humidity is more than 95%, the disease can occur 3 days after the bacteria invade. The disease is easy to be induced by low-lying terrain, heavy soil, poor drainage, poor permeability of planting, insufficient fertilization or too much nitrogen fertilizer, skin wounds caused by extensive management, or falling leaves due to leaf spot disease, fruits exposed to strong sun, and so on.

Prevention and control methods: to prevent and control anthracnose of ginger, cultivation and disease control should be strengthened, combined with spray protection.

1) reduce the source of bacteria. Thoroughly clean the countryside, do not apply soil fertilizer mixed with disease and residual ginger accumulation but not completely mature, turn the soil deeply and reduce the source of primary infection.

2) rotation: do not continuous cropping or adjacent cropping with Solanaceae or other ginger crops. Can be rotated with Gramineae crops.

3) planting in high border and deep furrow, applying high quality organic base fertilizer, leveling the border surface, ploughing and cultivating soil in time, removing weeds, reducing field humidity and applying more phosphorus and potassium fertilizer.

4) spray protection: at the initial stage of the onset of ginger anthracnose, you can choose to spray 80% anthrax Fumei wettable powder 600750 times, 20% prochloraz EC 1000 times, 40% polysulfide suspension, 50% carbendazim wettable powder, 50% thiophanate wettable powder 1000 times, 50% chlorothalonil wettable powder 1000 times 77% of the wettable particulate powder can be sprayed once every 8-10 days, 3-4 times in a row.