The Plant as a Factor in the Action of Bordeaux Mixture as an Insecticide

Delong, D M; Reid, W. J.; Darley, M. M.

doi:10.1093/jee/23.2.383a

Cited by 4 publications

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“…Three hypotheses have been advanced in an attempt to explain fungicidal activity of copper compounds of zero or extremely low water solubility. Solubility was suggested to be increased by: (i) CO 2 dissolved in rain water and dew (Pickering, 1912; Reckendorfer, 1936); (ii) excretions from the plant (DeLong et al., 1930) or (iii) secretions or exudates by the fungus (Aderhold, 1899; Barker and Gimingham, 1911; McCallan and Wilcoxon, 1936; Martin et al., 1942; Wain and Wilkinson, 1943). In his review, McCallan (1949) concluded that it appears most likely that exudates from the fungal spore, such as amino acids and malate, dissolve copper fungicides and form toxic copper complexes.…”

Section: Introductionmentioning

confidence: 99%

An In Vitro Study of the Nature of Protective Activities of Copper Sulphate, Copper Hydroxide and Copper Oxide Against Conidia of Venturia inaequalis

Montag¹,

Schreiber²,

Schönherr³

2006

Journal of Phytopathology

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Section: Introductionmentioning

confidence: 99%

An In Vitro Study of the Nature of Protective Activities of Copper Sulphate, Copper Hydroxide and Copper Oxide Against Conidia of Venturia inaequalis

Montag¹,

Schreiber²,

Schönherr³

2006

Journal of Phytopathology

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“…There are three principal hypotheses that suggest different ways of increasing solubility and availability of copper in Bordeaux mixture as well as in other insoluble and slightly soluble copper compounds. Dissolution might be aided by (i) CO 2 and ammonium ions dissolved in rainwater or dew (14,16), (ii) exudates from the plant (17), and (iii) secretion of acids or complexing agents by the spore (18)(19)(20)(21)(22).…”

Section: Introductionmentioning

confidence: 99%

An in Vitro Study on the Postinfection Activities of Copper Hydroxide and Copper Sulfate against Conidia of Venturia inaequalis

Montag

Schreiber

Schönherr

2006

J. Agric. Food Chem.

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The postinfection activities of copper hydroxide [Cu(OH)2] and copper sulfate (CuSO4) against apple scab (Venturia inaequalis) were evaluated in an in vitro study. Our intention was to support the aim of reducing copper application rates by appropriate timing of applications. Experiments were conducted at 20 degrees C with leaf disks and isolated cuticular membranes (CM) of Malus x domestica 'Gloster' and 'Elstar'. Conidia of V. inaequalis were used as the inoculum. In untreated controls, 7.9 and 33.2% of germinated conidia formed primary stromata 24 and 48 h after inoculation, respectively. Treatments with copper compounds were applied 24 and 48 h after inoculation, which was 16 and 40 h after infection had occurred. When working with CM and using fluorescein diacetate as a vital stain, vital and dead stromata could be distinguished. Treatment effects were assessed 72 h after inoculation by counting vital (fluorescing) primary stromata. With leaf disks, the number of stromata was counted using KOH-aniline blue fluorescence staining. Cu(OH)2 and CuSO4 showed postinfection activity and killed primary stromata, provided that the surface of the CM was kept wet. Cu(OH)2 was more effective than CuSO4 and was able to kill all primary stromata 24 h after inoculation at concentrations of 116 and 231 mg L(-1). When Cu(OH)2 was applied at 116 mg L(-1) to leaf disks 24 h after inoculation, the number of primary stromata did not significantly differ from the control. Results indicate different modes of action for the highly water soluble CuSO4 and the slightly soluble Cu(OH)2. This supports the hypothesis that spore exudates react with insoluble copper compounds and form highly toxic copper complexes. Application of Cu(OH)2 to dry CM did not kill primary stromata. Hence, for Cu(OH)2 to exert postinfection activity, leaves must be wet. In the field, this cannot be guaranteed and a postinfection application of Cu(OH)2 cannot be recommended.

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Fungal Disease Management in Environmentally Friendly Apple Production – A Review

Holb

2009

Climate Change, Intercropping, Pest Control and Beneficial Microorganisms

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The Plant as a Factor in the Action of Bordeaux Mixture as an Insecticide

Cited by 4 publications

References 0 publications

An In Vitro Study of the Nature of Protective Activities of Copper Sulphate, Copper Hydroxide and Copper Oxide Against Conidia of Venturia inaequalis

An In Vitro Study of the Nature of Protective Activities of Copper Sulphate, Copper Hydroxide and Copper Oxide Against Conidia of Venturia inaequalis

An in Vitro Study on the Postinfection Activities of Copper Hydroxide and Copper Sulfate against Conidia of Venturia inaequalis

Fungal Disease Management in Environmentally Friendly Apple Production – A Review

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