Keep records of areas, fields, containers or beds that have a history of hosting root rot fungus. This pathogen frequently remains dormant in the soil as a spore. When the right conditions arise, it will multiply rapidly and become a serious problem.
Identify early signs of the disease whenever possible. Above-ground symptoms include excessive yellowing of needles or leaves near the crown, wilting, death of branches, and poor growth. The whole plant may begin to take on a bronze-colored appearance. These are also signs of many other diseases, so get a lab test for confirmation of a suspected case.
Select an appropriate treatment or management method. Phosphonate fungicides such as Chipco Aliette, Chipco Signature, Stature and Subdue MAXX will abate the growth of Phytophthora root rot. Unfortunately, the use of some fungicides will hurt efforts to build a certified organic stock. Isolation and irrigation review is often a viable alternative in these cases.
Apply fungicide to the affected plants by drenching or spraying. Use appropriate safety equipment such as gloves and goggles and adhere to all safety precautions on the label. Follow strict sanitization procedures for any containers that may have been contaminated with fungal spores.
Monitor the results. Consider performing monthly maintenance with low doses of fungicide as a cost-effective preventive measure.