POSTERS: Chemical control
Comparative performance of fungicides, biofungicides, host plant defense inducers, and fertilizer in suppression of Phytophthora root rot in boxwood
Mary Holden - Tennessee State University. Fulya Baysal-Gurel- Tennessee State University, Bharat Pokharel- Tennessee State University, Terri Simmons- Tennessee State University
Phytophthora root caused by Phytophthora nicotianae can affect all growth stages of field or container grown boxwood plants. Management of Phytophthora requires an integrated approach. The efficacy of fungicides, biofungicides, host plant defense inducers, and fertilizer against Phytophthora root rot of boxwood was assessed in field and greenhouse trials. Plots/pots were inoculated with P. nicotianae grown on rice grains. Plant growth data were recorded and roots were assessed for disease severity using a scale of 0-100% roots affected. At the end of the field trial, the treatments most effective in reducing Phytophthora disease severity were Orkestra Intrinsic, Subdue MAXX, Segovis, fertilizer ON-Gard alone and the RootShield PLUS++ fertilizer ON-Gard application program and disease severity for those treatments were not significantly different than the non-treated, non-inoculated control. All of the treatments except Subdue MAXX and Aliette resulted in a significantly greater plant height compared to the non-treated, inoculated control. At the end of the greenhouse trial, the treatments most effective in reducing Phytophthora disease severity were Orkestra Intrinsic, Empress Intrinsic and Orvego and disease severity for those treatments were not significantly different than the non-treated, non-inoculated control. There were no significant differences in plant growth between treated and non-treated control plants.