How to Treat Phytophthora Root Rot


Phytophthora root rot, caused by the phytophthora fungus, causes roots to collapse and rot in the soil. Early signs include yellow leaves, lack of new growth and burning on the margins of leaves. Leaves wilt and begin to drop as the infection progresses. Leaves may show signs of rot at the stems and appear water-soaked. Roots turn black and mushy as they decay in the soil. When detected early, some plants can be revived, but if undetected, the plant perishes.

Step 1

Check the roots of plants to determine the extent of the infection. Mushy dark roots have already experienced decay. Healthy young roots appear white or cream colored.

Step 2

Trim away damaged roots. If the infection is not extensive and healthy, roots remain, the plant may be saved.

Step 3

Remove soil from the roots ,as phytophthora fungi thrive in the soil. Discard old soil.

Step 4

Disinfect the plant pot in a solution of one part bleach and nine parts water. Soak in the solution for 30 minutes. Allow to dry naturally.

Step 5

Place pebbles in the bottom of the pot to improve drainage; damp soggy soil promotes rot root.

Step 6

Fill one-half to three-quarters of the pot with fresh sterilized soil.

Step 7

Position the plant in the pot to the original planting depth and fill in around the roots with fresh soil. Firm down with your hands to secure the plant and remove air pockets.

Step 8

Water to moisten soil. Follow the watering recommendation for your specific plant using care not to allow roots to sit in soggy soil.

Things You'll Need

  • Sterilized potting soil
  • Sharp knife
  • Household bleach
  • Pebbles


  • University of Minnesota Extension: Root rot in Houseplants
  • North Carolina State University: Phytophthora Root Rot in Blueberry
  • University of Wisconsin: Phytophthora Root and Stem Rot in Wisconsin

Who Can Help

  • Clemson University: Phytophthora Root and Crown Rot
  • University of California Agriculture and Natural Resources: Phytophthora Root and Crown Rot
Keywords: root rot, phytophthora root rot, phytophthora fungus

About this Author

Nannette Richford is an avid gardener, teacher and nature enthusiast with 4 years experience in online writing and a lifetime of personal journals. She is published on various sites, including Associated Content. Richford holds a Bachelor of Science in secondary education from the University of Maine Orono and certifications in 7-12 English, K-8 General Elementary and Birth to age 5.