Ed from Jacksonville, Florida writes
Monterey Garden Phos Systemic Fungicide can be applied as a soil drench to ornamentals at a rate of 1/8 tsp per gallon of water, apply each 25 gallons of solution to an area of 100 sq. ft. and you could also do a foliar spray at a rate of 2 tsp to 4 tsp per gallon of water. Please review product label for complete application instructions. Although we have found some conflicting information, the most recommended method and most effective way of preventing Phytophthora root rot disease is to provide good drainage and to practice good water management. Don't over irrigate the soil more than necessary and the beddings are in an area where the soil will tend to stay moist, consider planting trees and shrubs on mounds, especially in an area where you know Phytophthora is present. While Fungicides help, they recommend that you do not rely on fungicide applications alone to control root and crown rot diseases. Please view this article by the University of California Extension on Phytophthora Root and Crown Rot in the Garden for more information and also, we would recommend contacting your local extension office and speak with the Master Gardener directly for fungicide rotation recommendations that have been studied and tested in your county.
Answer last updated on: 09/03/2021