Root & Crown Rot of pansy

Disease Information

Root & Crown Rot

Symptoms and damage

Manyfungi Phytophthora species, Pythium species, Rhizoctonia species and Fusarium species) live in the soil, which can infect the roots or the base of the plant (crown) at the soil line. Plants may wilt and suddenly die or the leaves may simply turn yellow. A dark sunken area may be seen on the stem at or near the soil line. Roots may appear rotted. Some plants may survive but remain weak and stunted.

Management

The fungus thrives in areas with poor drainage and warm soils. Always choose locations that have good drainage for planting. The drainage of existing areas can be improved by using raised beds. Avoid applying too much water since many of these fungi thrive in moist conditions. Always allow the soil to dry between each watering. Promote drying of the soil by not setting plants too close or applying too much mulch around plants. Prevent future infection by always removing and destroying diseased plants.

Fungicides can be effective on a preventative basis only, and repeat applications are required. Fungicides containing potassium salts of phosphorous acid (such as Monterey Agri-Fos, Fosphite, Agri-Fos 400) or mefenoxam (Subdue Maxx) can be applied as a drench in the home landscape, and will suppress, but not cure infected plants.

 



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