The leaves of green plants will turn black and fall off. What is the reason?

The blackening of green leaves is generally a symptom of root rot caused by excessive watering.

One: the phenomenon that leaves are soft and drooping due to excessive watering. Usually watering is not easy to get too wet. Too wet soil tends to accumulate water and cause root rot. After root rot is seriously infected by bacteria, roots, leaves and stems will all become ill. Such as anthracnose and leaf spot.

Plant anthracnose: it mainly harms immature or mature fruits, but also flowers, leaves, spindles and bananas. Pathogens can directly show symptoms through wound invasion, or they can infect undamaged olives, and symptoms only show when bananas become Huang Shi after harvest. Black or dark brown dots were born, and then they quickly expanded and connected into pieces. After 2-3 days, the whole fruit turns black and rots, and a large number of orange-red sticky spots are produced on the diseased spots, that is, there are no umbilicus and conidia. 70% thiophanate methyl 800 times solution and 50% carbendazim 1 000 times solution can be sprayed at the initial stage of onset.

Green plant leaf spot: a fungal disease that harms leaves, stems and buds. The lesions on the leaves are round or oblong, and then irregular reddish-brown lesions are scattered, with gray centers and small black spots. The diseased spots on the stems and branches are long and grayish brown, and a black mold layer is produced in the later stage. 1% bordeaux solution, 25% carbendazim WP 500 times solution, 50% thiophanate 1000 times solution and 80% zineb 500 times solution.