A susceptible variety of three-year-old potted Buxus sempervirens ‘Suffruticosa’ was used for the trials. In Year one, seven fungicides including Stroby WG, Delsene 50 Flo, Bravo 500, Octave, Amistar, Fungus Clear and Opponent were applied as protectant and curative foliar sprays. In Year two, the fungicides Opera, Bravo 500, Octave, Stroby WG and Fungus Clear were applied as either protectant or curative foliar sprays. They were also used in several different combinations. Year three is a repeat of Year two with the addition of the fungicide Signum.
The trial was scored for phytotoxicity and disease. Disease was assessed at three days after inoculation and then again at six and 13 days after each of three curative fungicide applications applied at seven-day intervals. Disease assessment continued over a period of three to five months to find out if the disease recovered once the fungicide sprays had stopped. Disease severity records included percentage leaf spot, percentage leaf drop, percentage of streaking, percentage stem dieback. The trials are still in progress.
The field trials are taking place outdoors over a period of three years, in ADAS Arthur Rickwood in Year one and two and in ADAS Boxworth, in Year three. Both sites are located near Cambridge.