Open AccessEfficacy of Some Essential Oils on Controlling Powdery Mildew on Zinnia (Zinnia Elegans, L.)
Author(s) -
M. A. Hegazi,
G. A. N. El-Kot
Publication year - 2010
Publication title -
journal of agricultural science
Language(s) - English
Resource type - Journals
eISSN - 1916-9760
pISSN - 1916-9752
DOI - 10.5539/jas.v2n4p63
Subject(s) - powdery mildew , polyphenol oxidase , biology , horticulture , fungicide , shoot , botany , peroxidase , biochemistry , enzyme
Some essential oils were evaluated as biocontrol agents against powdery mildew on Zinnia elegans, L. A field experiment was carried out during the two successive seasons of 2006 and 2007 using marjoram, clove, cinnamon, garlic, ginger and fennel oils, added as foliar spray at 2 levels of 0.05 and 0.1 ppm besides Kema zein 75% and distilled water as a control. Disease incidence and severity as well as other vegetative parameters such as plant height, number of branches per plant, leaf area, fresh and dry weights of shoots, root length and fresh and dry weights of roots were determined in the two seasons. Also, peroxidase and polyphenol oxidase activities were determined after 24 hour from the last spray in leaves samples. The highest significant decrease in disease incidence and severity and the best results for most studied growth and flowering parameters and total green colour were recorded with ginger, cinnamon and clove oils, respectively each at 0.1 ppm compared to the other treatments in both seasons. In addition, the activities of peroxidase (POX) and polyphenol oxidase (PPO) enzymes were increased as a result of oils sprayed on plants. These findings provide for a rational basis of a possible utilization of these essential oils as a safe and alternative method to fungicides for controlling powdery mildew of Zinnia plants