What to Do When Impatiens Gets Mosaic Disease? A Detailed Guide to Prevention and Control Methods

Symptoms The disease occurs at the root crown. At first the root crown turns brown and constricts, later causing damping-off symptoms. Generally, in flower beds during the plum rain season, and when potted flowers are too wet, the disease occurs more frequently.

Pathogen PhytophthoranicotianaevanBredadeHaanvar.parasitica(Dastur)Waterhouse

Transmission routes and disease conditions The pathogen overwinters in seeds or as mycelium and oospores with diseased plant debris in the soil, and spreads through wind, rain and irrigation water. The pathogen infects seedlings and causes lodging; at the mature plant stage, frequent rain and high humidity make the disease more likely to occur. The optimum temperature for pathogen development is 27-31°C, with a maximum of 36°C and a minimum of 10°C. When there is continuous rain or high humidity, or when the soil is heavy, the terrain is low-lying, or there is continuous cropping, the disease is more severe.

Prevention and Control Methods

1. Remove diseased leaves; apply more phosphorus and potassium fertilizers, etc.

2. At the early stage of the disease, spray 75% Baijunqing wettable powder at 500-600 times dilution, or 40% triethyl phosphonate aluminum (phosethyl-Al) wettable powder at 200 times dilution, 70% phosethyl-Al o mancozeb wettable powder at 500 times dilution, 58% metalaxyl o mancozeb at 400-500 times dilution, 72.2% Previcur water solution at 700-800 times dilution, 64% Sandofan wettable powder at 500 times dilution.