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W.J. Hill, J.R. Heckman, B.B. Clarke, and J.A. Murphy

Take-all patch, caused by Gaeumannomyces graminis (Sacc.) Arx. & D. Olivier var. avenae (E.M. Turner) Dennis (Gga), is a disease of creeping bentgrass (Agrostis stolonifera Huds.), which most often is associated with golf courses. Synthesis of ligneous and phenolic compounds by plants requires adequate Mn+2 and Cu+2 nutrition and may be a factor in disease resistance. An experiment was conducted on a creeping bentgrass fairway naturally infested with Gga to determine if foliar applications of Mn+2 (1.02 and 2.04 kg·ha–1 per application) and Cu+2 (0.68 kg·ha–1 per application) would reduce take-all severity. Prior to initiating treatments, soil pH was 6.4 and Mehlich-3 extractable Mn+2 and Cu+2 were 5 mg·kg–1 and 1.7 mg·kg–1, respectively. Manganese and copper sulfate treatments were initiated in July 1995 and foliarly applied every 4 weeks through 1997 with the exception of December, January, and February. Disease incidence was decreased from 20% on untreated turf to 5% with the high rate of MnSO4. For both years, turf treated with the high rate of Mn+2 had less disease than turf receiving the low rate of Mn+2. The application of CuSO4, however, did not influence disease development.

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Meredith V. Melendez, Joseph R. Heckman, Stephanie Murphy, and Frank D’Amico

Fruit and vegetable growers have historically relied on copper-based fungicides for disease prevention and suppression. Elevated disease pressure on tomato ( Solanum lycopersicum ) from late blight ( Phytophthora infestans ) has increased the need

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Youbin Zheng, Linping Wang, Diane Feliciano Cayanan, and Mike Dixon

conventional control methods (i.e., pesticides and biological control agents), but there has been much exploration on new control methods such as ozone and ultraviolet treatment of nutrient solutions ( Graham et al., 2009 ; Zheng et al., 2005 ). Copper (Cu 2

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Barrett R. Gruber, Libby R.R. Davies, and Patricia S. McManus

-resistant strains of B. jaapii ( Proffer et al., 2006 ). Copper-based fungicides, which were widely used for CLS management in the early 1900s ( Keitt et al., 1937 ), are therefore being reintroduced for CLS control ( McManus et al., 2007 ). An appealing feature

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Jie Li, Scott M. Leisner, and Jonathan Frantz

The transition metal copper (Cu) is an essential element for all organisms. Copper functions as a cofactor within plant cells in a variety of physiological processes, including electron transfer in photosynthesis, mitochondrial respiration

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Youbin Zheng*, Linping Wang, Weizhong Liu, John Sutton, and Mike Dixon

Copper is one of the essential micro-nutrient elements for plants, but when in excess, is toxic to plants and other living organisms. Electrolytically generated copper and cupric sulphate are increasingly used by the greenhouse industry to control diseases and algae in hydroponic systems. However, there is little information regarding appropriate strategies for employing copper in greenhouse crop production. We investigated the physiological responses, growth and production of several ornamental crops (miniature rose, chrysanthemum and geranium) and greenhouse vegetable crops (pepper, cucumber, and tomato) with respect to Cu2+ concentration in the root zone. Tests were conducted using plants grown in nutrient solution, Promix and rockwool. Results showed that phytotoxic levels of Cu2+ were dependent on the crop species and growing substrate. Plants grown in nutrient solution exhibited symptoms of phytotoxicity at lower Cu2+ concentrations than those on the solid substrates. The ability of copper to control Pythium aphanidermatum and green algae was evaluated under both laboratory and greenhouse conditions. Copper was effective in suppressing green algae in nutrient solution, but did not control Pythium effectively. This presentation is a comprehensive summary of the research conducted over the last three years by our group on copper application in greenhouse systems.

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Vladimir Orbović, Diann Achor, and James P. Syvertsen

Copper (Cu) is an important component of the fungicide programs that are used for control of many important diseases of citrus. Copper-based fungicides, used either alone or with spray oil, can successfully control greasy spot, melanose, citrus

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Jonathan M. Frantz, Sushant Khandekar, and Scott Leisner

of Agriculture (USDA) statistics account for this source of Cu, so the extent of electrolytically generated Cu use is not known. Recommended rates of Cu ionization are from 7.8 to 15.7 μ m . Additional Cu use is primarily from copper hydroxide [Cu

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El-Sayed Mohamed El-Mahrouk, Eman Abdel-Hakim Eisa, Mahmoud Abdelnaby Hegazi, Mohamed El-Sayed Abdel-Gayed, Yaser Hassan Dewir, Mohammed Elsayed El-Mahrouk, and Yougasphree Naidoo

–protein complexes, and the development of thylakoid membranes are highly disturbed ( Basa et al., 2014 ). Copper (Cu) is an important essential micronutrient that participates in many vital physiological functions of plants, including acting as a catalyzer of redox

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Suphasuk Pradubsuk and Joan R. Davenport

- to four-leaf stage, whereas the highest Cu concentration was found in shoot tips at the three- to four-leaf stage as well as in leaf blades, petioles, and clusters at bloom. Copper concentrations in annual tissues significantly decreased from bloom to