Bordeaux mixture

Last updated
Bordeaux mixture in preparation Calda Bordalesa.jpg
Bordeaux mixture in preparation
Bordeaux mixture on grapes Bourdeaux mixture.jpg
Bordeaux mixture on grapes

Bordeaux mixture (also called Bordo Mix) is a mixture of copper(II) sulphate (CuSO4) and quicklime (Ca O) used as a fungicide. It is used in vineyards, fruit-farms, vegetable-farms and gardens to prevent infestations of downy mildew, powdery mildew and other fungi. It is sprayed on plants as a preventive treatment; its mode of action is ineffective after a fungus has become established. It was invented in the Bordeaux region of France in the late 19th century. If it is applied in large quantities annually for many years, the copper in the mixture eventually becomes a pollutant. As such its use is controlled, but not forbidden in most of the European Union. [1] Despite this, some advocates of organic gardening consider it an 'organic' pesticide.

Contents

Main uses

In addition to its use to control fungal infection on grape vines, the mixture is also widely used to control potato blight, peach leaf curl and apple scab. Although it may be bad for the environment, [1] [2] some organic agriculture advocates allow its use,[ citation needed ] so is often used by organic gardeners in some parts of the world. [3]

Because the copper ions build up in the soil, continuous use will cause heavy metal pollution. Copper also bioaccumulates in organisms. It is thus restricted to use under control in 18 of the 27 European Union countries, with the exception of Cyprus, Greece, Bulgaria, Hungary, Italy, Malta, Portugal, Romania and Slovenia. [1]

Mode of action

Bordeaux mixture achieves its effect by means of the copper ions (Cu2+) of the mixture. These ions affect enzymes in the fungal spores in such a way as to prevent germination. This means Bordeaux mixture must be used preventively, before the fungal disease has struck.

Thorough coverage of the spray on the plants is necessary. The Bordeaux spray continues to adhere well to the plant during rain, though in the long term it is washed off by rain. Commonly in practice, it is applied just once a year, in the wintertime. [4]

Preparation

Bordeaux mixture can be prepared using differing proportions of the components. In preparing it, the CuSO4 and the lime are dissolved separately in water and then mixed. Calcium oxide (burnt lime) and calcium hydroxide (slaked lime) give the same end result, since an excess of water is used in the preparation.

The conventional method of describing the mixture's composition is to give the weight of CuSO4, the weight of hydrated lime and the volume of water, in that order. The percentage of the weight of CuSO4 to the weight of water employed determines the concentration of the mixture. Thus a 1% Bordeaux mixture, which is typical, would have the formula 1:1:100, with the first "1" representing 1 kg CuSO4 (pentahydrated), the second representing 1 kg hydrated lime, and the 100 representing 100 litres (100 kg) water. As CuSO4 contains 25% copper, the copper content of a 1% Bordeaux mixture would be 0.25%. The quantity of lime used can be lower than that of the CuSO4. One kg of CuSO4 actually requires only 0.225 kg of chemically pure hydrated lime to precipitate all the copper. Good proprietary brands of hydrated lime are now freely available, but, as even these deteriorate on storage (by absorbing carbon dioxide from the air), a ratio of less than 2:1 is seldom used, which corresponds to a 1:0.5:100 mixture.

Risks

Bordeaux mixture has been found to be harmful to fish, livestock and—due to potential buildup of copper in the soil—earthworms. [1] [2]

The chemical was in use as a blight preventive in the potato country of northern Maine by 1921. [5] It started to be used by the United Fruit Company throughout Latin America around 1922. The mixture was nicknamed perico, or "parakeet", because it would turn workers completely blue. Many workers would get sick or die of copper poisoning. [6]

History

In the 19th century, several outbreaks of vine diseases occurred among the Vitis vinifera vines of the classical European wine regions. These outbreaks were caused by pests to which these vines lacked resistance, carried on vines brought to Europe as botanical specimens of American origin. These pests included not only the Great French Wine Blight caused by the aphid Phylloxera vastatrix , but also mildew and other diseases caused by fungi. [7] [note 1]

After the downy mildew had struck, botany professor Pierre-Marie-Alexis Millardet of the University of Bordeaux studied the disease in vineyards of the Bordeaux region. Millardet then noted that vines closest to the roads did not show mildew, while all other vines were affected. After inquiries, he found out those vines had been sprayed with a mixture of CuSO4 and lime to deter passersby from eating the grapes, since this treatment was both visible and bitter-tasting. This led Millardet to conduct trials with this treatment. The trials primarily took place in the vineyards of Château Dauzac, where he was assisted by Ernest David, Dauzac's technical director. Millardet published his findings in 1878, and recommended the mixture to combat downy mildew.

In France, the use of Bordeaux mixture has also been known as the Millardet-David treatment.

See also

Notes

  1. Some of these diseases are caused by fungi-like organisms in the Oomycete group, which no longer are considered fungi. Since they are more closely related to the algae, they are currently classified as part of the heterokonts, but the term "fungal diseases" is fairly well established as an umbrella term.

Related Research Articles

<span class="mw-page-title-main">Copper(II) sulfate</span> Chemical compound

Copper(II) sulfate is an inorganic compound with the chemical formula CuSO4. It forms hydrates CuSO4·nH2O, where n can range from 1 to 7. The pentahydrate (n = 5), a bright blue crystal, is the most commonly encountered hydrate of copper(II) sulfate, while its anhydrous form is white. Older names for the pentahydrate include blue vitriol, bluestone, vitriol of copper, and Roman vitriol. It exothermically dissolves in water to give the aquo complex [Cu(H2O)6]2+, which has octahedral molecular geometry. The structure of the solid pentahydrate reveals a polymeric structure wherein copper is again octahedral but bound to four water ligands. The Cu(II)(H2O)4 centers are interconnected by sulfate anions to form chains.

Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals. Fungicides are also used to control oomycetes, which are not taxonomically/genetically fungi, although sharing similar methods of infecting plants. Fungicides can either be contact, translaminar or systemic. Contact fungicides are not taken up into the plant tissue and protect only the plant where the spray is deposited. Translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower, unsprayed surface. Systemic fungicides are taken up and redistributed through the xylem vessels. Few fungicides move to all parts of a plant. Some are locally systemic, and some move upward.

<span class="mw-page-title-main">Powdery mildew</span> Fungal plant disease

Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as the signs of the causal pathogen are quite distinctive. Infected plants display white powdery spots on the leaves and stems. This mycelial layer may quickly spread to cover all of the leaves. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.

<span class="mw-page-title-main">Downy mildew</span> Name for several species of oomycete

Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of crucifers, grapes and vegetables that grow on vines. The prime example is Peronospora farinosa featured in NCBI-Taxonomy and HYP3. This pathogen does not produce survival structures in the northern states of the United States, and overwinters as live mildew colonies in Gulf Coast states. It progresses northward with cucurbit production each spring. Yield loss associated with downy mildew is most likely related to soft rots that occur after plant canopies collapse and sunburn occurs on fruit. Cucurbit downy mildew only affects leaves of cucurbit plants.

A Biopesticide is a biological substance or organism that damages, kills, or repels organisms seens as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships.

In horticulture, lime sulfur (lime sulphur in British English, see American and British English spelling differences) is mainly a mixture of calcium polysulfides and thiosulfate (plus other reaction by-products as sulfite and sulfate) formed by reacting calcium hydroxide with elemental sulfur, used in pest control. It can be prepared by boiling in water a suspension of poorly soluble calcium hydroxide (lime) and solid sulfur together with a small amount of surfactant to facilitate the dispersion of these solids in water. After elimination of residual solids (flocculation, decantation, and filtration), it is normally used as an aqueous solution, which is reddish-yellow in colour and has a distinctive offensive odor of hydrogen sulfide (H2S, rotten eggs).

<i>Uncinula necator</i> Species of fungus

Uncinula necator is a fungus that causes powdery mildew of grape. It is a common pathogen of Vitis species, including the wine grape, Vitis vinifera. The fungus is believed to have originated in North America. European varieties of Vitis vinifera are more or less susceptible to this fungus. Uncinula necator infects all green tissue on the grapevine, including leaves and young berries. It can cause crop loss and poor wine quality if untreated. The sexual stage of this pathogen requires free moisture to release ascospores from its cleistothecia in the spring. However, free moisture is not needed for secondary spread via conidia; high atmospheric humidity is sufficient. Its anamorph is called Oidium tuckeri.

<span class="mw-page-title-main">Black rot (grape disease)</span> Species of fungus

Grape black rot is a fungal disease caused by an ascomycetous fungus, Guignardia bidwellii, that attacks grape vines during hot and humid weather. “Grape black rot originated in eastern North America, but now occurs in portions of Europe, South America, and Asia. It can cause complete crop loss in warm, humid climates, but is virtually unknown in regions with arid summers.” The name comes from the black fringe that borders growing brown patches on the leaves. The disease also attacks other parts of the plant, “all green parts of the vine: the shoots, leaf and fruit stems, tendrils, and fruit. The most damaging effect is to the fruit”.

<span class="mw-page-title-main">White onion</span> Onion cultivar

White onion or Allium cepa are a cultivar of dry onion which have a distinct light and mild flavour profile. Much like red onions, they have a high sugar and low sulphur content, and thus have a relatively short shelf life. White onions are used in a variety of dishes, such as those of Mexican and European origin. Their uses in dishes often relate to their mild nature, they are often included in dishes to provide a light, fresh and sour taste to dishes and are often added uncooked to dishes such as salads.

<span class="mw-page-title-main">Burgundy mixture</span>

Burgundy mixture, named after the French district where it was first used to treat grapes and vines, is a mixture of copper sulfate and sodium carbonate. This mixture, which can have an overall copper concentration within the range of 1% through 20%, is used as a fungicidal spray for trees and small fruits.

<span class="mw-page-title-main">Pierre-Marie-Alexis Millardet</span> French botanist and mycologist (1838–1902)

Pierre-Marie-Alexis Millardet was a French botanist and mycologist born in Montmirey-la-Ville.

<span class="mw-page-title-main">Château Dauzac</span> French winery

Château Dauzac is a winery in the Margaux appellation of the Bordeaux region of France, in the commune of Labarde. The wine produced here was classified as one of eighteen Cinquièmes Crus in the Bordeaux Wine Official Classification of 1855. It is now a family winery and owned by the Roulleau family.

<span class="mw-page-title-main">Damping off</span> Horticultural disease or condition

Damping off is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions.

<i>Plasmopara viticola</i> Species of single-celled organism

Plasmopara viticola, the causal agent of grapevine downy mildew, is a heterothallic oomycete that overwinters as oospores in leaf litter and soil. In the spring, oospores germinate to produce macrosporangia, which under wet condition release zoospores. Zoospores are splashed by rain into the canopy, where they swim to and infect through stomata. After 7–10 days, yellow lesions appear on foliage. During favorable weather the lesions sporulate and new secondary infections occur.

Pseudoperonospora cannabina is a plant pathogen that causes downy mildew, which is a fungal-like disease caused by an oomycete.

This glossary of viticultural terms list some of terms and definitions involved in growing grapes for use in winemaking.

This article summarizes different crops, what common fungal problems they have, and how fungicide should be used in order to mitigate damage and crop loss. This page also covers how specific fungal infections affect crops present in the United States.

Copper pesticides are copper compounds used as bactericides, algaecides, or fungicides. They can kill bacteria, oomycetes and algae, and prevent fungal spores from germinating. Common forms of fixed copper fungicides include copper sulfate, copper sulfate pentahydrate, copper hydroxide, copper oxychloride sulfate, cuprous oxide, and copper octanoate.

Plant pathology has developed from antiquity, but scientific study began in the Early modern period and developed in the 19th century.

Trunk injection or endotherapy also known as vegetative endotherapy, is a method of target-precise application of pesticides, plant resistance activators, or fertilizers into the xylem vascular tissue of a tree with the purpose of protecting the tree from pests, or to inject nutrients to correct for nutrient deficiencies. This method largely relies on harnessing the tree's vascular system to translocate and distribute the active compounds into the wood, canopy and roots where protection or nutrition is needed.

References

  1. 1 2 3 4 "Bordeaux mixture". PPDB: Pesticide Properties DataBase. University of Hertfordshire. 23 February 2021. Retrieved 11 July 2021.
  2. 1 2 Pears, Pauline, et al. HDRA Encyclopedia Of Organic Gardening, pp103, Dorling Kindersley Ltd, London, 2005.
  3. "What is "Bordeaux Mixture?"".
  4. "Bordeaux Mixture" @ Integrated Pest Management @ UC Davis.
  5. https://www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/maine/aroostookME1921/aroostookME1921.pdf Hurst, Lewis A. (1921) Soil Survey of the Aroostook Area, Maine, p.13
  6. Koeppel, Dan (2008). Banana : the fate of the fruit that changed the world. New York: Hudson Street Press. p. 108. ISBN   978-1-59463-038-5. OCLC   173218748.
  7. Suryanarayanan, T. S. (25 October 2024). "A historic perspective of Bordeaux mixture: the first commercial scale fungicide" (PDF).