Control Methods for Root Rot in Salvia miltiorrhiza Cultivation
1. Hazard symptoms: Root rot of Salvia miltiorrhiza occurs in hot and rainy seasons and damages the plant roots. In the early stage, only a few roots or part of the underground rhizome are affected first, gradually spreading to the entire root system. After the roots are damaged, wet rot occurs, the outer skin turns black, and in the early stage of aboveground disease, some branches and leaves wither and die, and in severe cases the whole plant withers and dies. Root rot occurs to varying degrees in all Salvia miltiorrhiza production areas, causing certain losses.
2. Control methods
1. Implement crop rotation: Because the soil carries the pathogen, continuous cropping of Salvia miltiorrhiza leads to early onset, severe disease, and rapid spread. It is best to rotate with grass-family crops for 3-5 years to reduce the pathogen population and lower the disease incidence.
2. Healthy seed selection: Choose disease-resistant varieties; choose robust, disease-free seed roots; do not save seeds from diseased fields, so as to reduce disease.
3. Strengthen field management: Fertilize reasonably, apply more organic fertilizer, and increase phosphorus and potassium fertilizer; drain standing water promptly during the rainy season, pay attention to loosening the soil, and improve the plants' disease resistance.
4. Chemical control: Per mu, mix 1 kg of 70% Dexon wettable powder or 50% carbendazim wettable powder with 3 kg of fine soil, and scatter it into the holes when planting, which has a certain control effect; disinfect cuttings and reed heads by soaking cuttings and reed heads in 800 times dilution of 50% Tuzet wettable powder or 1000 times dilution of 70% thiophanate-methyl wettable powder for 3-5 minutes, then air-dry before planting; apply pesticide during the growing period. In the early stage of disease onset in Salvia miltiorrhiza, pour fungicide around the roots of diseased plants to control the spread of the disease. Commonly used pesticides include 500-800 times dilution of 50% Shu-jun-ling wettable powder or 50% Dexon wettable powder, or 1000 times dilution of 96% copper sulfate, or 100-150 times dilution of 3% Nongkang 120 aqueous solution, applied once every 10-15 days for 3-4 consecutive times.