Flutriafol Drench Provides Season-long Protection of Boxwood Plantings Pre-infected by Calonectria pseudonaviculata in the Mid-Atlantic.

Abstract

Flutriafol drench application on March 7 without and with additional applications at 8- and 20-week intervals all consistently protected boxwood plantings pre-infected by Calonectria pseudonaviculata in two gardens in Richmond, Virginia through November 21. All drench applications were dosed at 2 ml product with 42% flutriafol and delivered in 250 ml solution per 30.5-cm shrub height in both gardens. While providing season-long protection, this drench dose also resulted in significant phytotoxicity on 30.5-cm tall 'Justin Brouwers' boxwood but not on English and common boxwood, which were 1.4 and 1.1 m tall, respectively. Once the phytotoxicity issue is resolved, only a single drench per year may suffice to protect boxwood plantings in the Mid-Atlantic, which would substantially cut the labor cost and minimize the health impacts commonly associated with current fungicide foliar sprays.