What is the difference between damping-off disease and Rhizoctonia rot

There are many differences between damping-off disease and Rhizoctonia rot: their pathogens differ, the types of plants they damage differ, the timing of onset differs, the symptoms differ, and the control methods also differ. Damping-off disease often occurs after the seedlings emerge and before the true leaves have unfolded, and the suitable soil temperature for onset is 10°C; generally the seedlings topple over and die. Rhizoctonia rot mostly occurs in the middle and late stages of seedling raising, often arising under scorching hot and high-temperature conditions, and generally the plants die standing upright.

1. Different pathogens

The pathogens of damping-off disease are fungi such as Pythium, Phytophthora and Rhizoctonia. The pathogen of Rhizoctonia rot is Rhizoctonia solani of the genus Rhizoctonia.

2. Different types of plants damaged

Besides damaging pepper and other solanaceous vegetables, damping-off disease can also harm the seedlings of cucumbers and other cucurbits, lettuce, celery, Chinese cabbage, cabbage, radish, onion and other vegetables. Besides solanaceous and cucurbit vegetables, Rhizoctonia rot can also damage some leguminous, cruciferous and other vegetables.

3. Different timing of onset

Damping-off disease often occurs after the seedlings emerge and before the true leaves have unfolded, and the suitable soil temperature for onset is 10°C. Rhizoctonia rot mostly occurs in the middle and late stages of seedling raising, often arising under scorching hot and high-temperature conditions.

4. Different symptoms

Seedlings mostly contract damping-off disease from the base of the stem; after the pathogen infects, a water-soaked dark spot appears at the base of the young stem, then spreads around the stem and gradually constricts into a thin thread-like shape, causing the aboveground part of the seedling to topple over because it loses its supporting ability. Rhizoctonia rot mainly harms the base of the seedling stem or the underground roots; in the early stage of infection, the seedling shows elliptical or irregular dark brown lesions, the diseased part gradually sinks and constricts, and some gradually turn black-brown; when the lesion expands all the way around the stem, the plant finally dries up and dies.

5. Different control methods

Before the onset of damping-off disease or in the early stage of onset, spray with a 400-fold dilution of 72.2% Previcur SL, applying 2 to 3 kg of spray solution per sq m, and at onset use a 400-fold dilution of copper-ammonium preparation. In the early stage of Rhizoctonia rot onset, spray a 800-fold dilution of 38% oxadixyl-pyrimethanil-copper fungicide, or a 600-fold dilution of 41% polycarbamate · pyrimethanil, etc. for control.