Disease Prevention and Care Methods for Herbaceous Flower Seedlings

Damping-off and Rhizoctonia rot are common diseases in the seedling stage of herbaceous flowers and are the two most important diseases. The pathogen of damping-off is mainly Pythium aphanidermatum; the pathogen of Rhizoctonia rot is Rhizoctonia solani. The main conditions for these two diseases are:

1. The soil remains at high temperature for a long time.

2. The temperature is unfavorable to the host, that is, plants suited to growing at higher temperatures encounter low temperatures; plants suited to germinating and growing at lower temperatures encounter high temperatures.

3. Too much nitrogen fertilizer in the soil, and the seedlings grow slowly and are weak and thin.

4. Continuous cropping land with a high pathogen load.

Prevention and control methods:

1. Avoid continuous cropping, especially in heavily affected plots. Before sowing, the soil should be fully turned and sun-dried, and disinfected. Chemicals such as carbendazim and thiophanate can be used. Apply according to the instructions.

2. Diseased plants that have already developed Rhizoctonia rot should be pulled out and burned promptly to prevent sclerotia from falling into the soil, and medicine or lime should be scattered on the diseased holes. Sometimes sclerotia can be mixed in with the seeds, so seeds can be treated with 10% salt water.

3. Improve growing conditions, cultivate strong seedlings, and increase disease resistance. Apply more decomposed fertilizer, control irrigation, do not let the soil become too warm, and sow at the right time so that the plants are not affected by low temperatures.

4. In the early stage of the disease, use chemicals for control to prevent the disease from spreading. Generally, spray 2-3 times in succession at an interval of about 10 days, applying to the roots, stems, and ground. Chemicals can be chosen from 50% carbendazim wettable powder or 50% thiophanate wettable powder and Yumiaoling, etc.