Reduction of Landscape Pathogens in Florida by Soil Solarization

Area of Science:

• Plant Pathology
• Horticultural Science
• Soil Science

Background:

• Soilborne pathogens and nematodes significantly impact impatiens cultivation, causing diseases like Rhizoctonia crown rot and root-knot.
• Effective management strategies are crucial for maintaining impatiens health and productivity in commercial settings.

Purpose of the Study:

• To evaluate the efficacy of soil solarization, alone and with biological control agents and a fungicide, for managing soilborne pathogens in impatiens.
• To assess the impact of these treatments on disease incidence, nematode populations, and plant growth.

Main Methods:

• Two field experiments were conducted in Florida using soil solarization with double-layer polyethylene mulch for 47-48 days.
• Treatments included soil solarization alone, in combination with Streptomyces lydicus (Actinovate), Pseudomonas chlororaphis (AtEze), and fludioxonil (Medallion).
• Evaluations focused on disease incidence, nematode population densities, root health, and shoot biomass of impatiens.

Main Results:

• Soil solarization significantly reduced Rhizoctonia crown rot and blight, Pythium root rot incidence, and root discoloration.
• Solarization also decreased root-knot severity and populations of several plant-parasitic nematodes, including Meloidogyne incognita.
• Fludioxonil reduced Rhizoctonia diseases, but biological control agents did not significantly impact pathogen or nematode levels.

Conclusions:

• Soil solarization is an effective method for managing a broad spectrum of soilborne pathogens and nematodes affecting impatiens.
• Integrated approaches, such as combining solarization with reduced-risk fungicides, can enhance disease control.
• Biological control agents tested showed limited efficacy in this study, suggesting further research is needed.