Control of powdery mildew on gerbera daisy with experimental and registered fungicide applications, 2008

摘要

Gerbera daisy ‘Festival Orange’ seedlings arrived at Michigan State University in early Jul. Plugs were transplanted into 6-in. plastic pots containing Baccto high porosity professional planting mix (Michigan Peat Company, Houston, TX).Plants were maintained in a glass research greenhouse and fertilized three times weekly with a 250 ppm Peter’s 20-20-20 liquid feed (The Scotts Company, Marysville, OH). Six replicates per treatment were arranged in a completely randomizeddesign. Plants received a preventive fungicide application before inoculation on 20 Jun. Fungicides were applied using a hand-pressurized sprayer until drip point. Plants were inoculated by being moved into a greenhouse containing activelysporulating Podosphaera xanthii on mature gerbera daisy plants. Subsequent fungicide applications were applied on 3 and 18 Jul, 6 and 20 Aug, except for treatments SP2050 and SP2059 where applications were made every seven days on 18 and25 Jun, 2, 9, 16, 26 and 30 Jul, and 3, 13, and 20 Aug. Disease severity was assessed by visually estimating the percent leaf area colonized by P. xanthii on 28 Jul, 4 and 29 Aug.