Master of Science (MS)
Plant, Environmental Management and Soil Sciences
Poinsettias are the number one flowering potted plant in the U.S. and it is the most popular Christmas plant sold. Miniature roses have become an increasingly important flowering potted plant. However, growers must overcome production problems to produce a quality finished plant and avoid disease incidence. Supplemental calcium has been proven to increase the amount of good quality flowers and increase disease resistance. Silicon can increase plant growth and crop quality and decrease disease pressures. Two experiments were conducted on miniature rose cultivars ‘Sonya’ and ‘Alto.’ The objective of experiment 1 was to determine the effects of preharvest application of calcium nitrate [Ca (NO3)2], Foli-Cal® (chelated Ca), chelate, Maniplex-Traffic® (chelated Si) or Sil-Matrix® (potassium silicate) applied as a spray or a drench on growth and development. Spray application of Foli-Cal® increased plant growth as indicated by a greater dry weight compared to all other treatment applications. Drench application of Foli-Cal® increased finished quality as indicated by greater flowering, height, width, leaf area, and dry weight. The objective of experiment 2 was to determine the efficacy of weekly spray applications of biofungicides Sil-Matrix™ (potassium silicate), Fosphite® (phosphoric acid), Kaligreen® (potassium bicarbonate), and Manniplex Traffic® (chelated Si) on powdery mildew on miniature roses compared to a standard fungicide Heritage® (azoxystrobin). Miniature roses treated with Kaligreen®, Heritage® alternated with Foshpite®, or Heritage® alternated with Kaligreen® were not as susceptible to powdery mildew. For the second study of powdery mildew, Kaligreen® gave the best control of powdery mildew for cultivar ‘Sonja’ but treatments for ‘Alto’ showed no significance.
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Robichaux, Mary Beth Louise, "The effect of calcium or silicon on potted miniature roses or poinsettias" (2008). LSU Master's Theses. 2681.
Jeff S Kuehny