Evaluation of Terrazole fungicide for control of Phytophthora root rot of snapdragon, 2006.

摘要

Seeds of ‘Rocket Red’ snapdragon were sown into a 288-cell plug flat and grown in a glass, research greenhouse at Michigan State University. Seedlings were transplanted into 4-in. plastic pots containing BACCTO Professional Planting Mix (Michigan Peat Company, Houston, TX) on 1 Aug, and maintained at 75deg F day and night. Plants were fertilized three times weekly with 250 ppm Peters 20-20-20 liquid feed (The Scotts Company, Marysville, OH). Six replicates per treatment were arranged in a completely randomized design. Phytophthora nicotianae inoculum was grown on-strength V8 agar plates for two wk under continuous fluorescent light. Mature cultures were flooded with distilled water for 20 min and 0.035 fl oz (1 ml) of the water/zoospore solution was injected by pipette into the soil at the base of each plant on 15 Aug, approximately 6 hr after fungicide application. Fungicides were applied as a drench in sufficient volume to displace approximately 10% of the liquid in the pots. Fungicides were applied at 7-day intervals on 15, 22, and 29 Aug except for Stature DM, which was applied at 14-day intervals. Plant health and percentage of plants dead were assessed on 22, 29 Aug, and 5 Sep.