Bordeaux is suitable for all deciduous fruit trees and is generally sprayed twice each year, at leaf fall in autumn and again in late winter. While it is quite a safe spray, gloves, face protection and other protective clothing should be worn. It should not be used after foliage has appeared.
To control peach leaf curl, which affects peaches and nectarines, spray just before buds start to open, generally in early August. It provides good early season control for brown rot in a variety of fruits and is also useful in controlling rust on raspberries and preventing early fungal attack on roses. Bordeaux works as a preventative, not a curative, so it will be necessary to re-spray following moderate to heavy rain. It generally survives light rain.
- Easy to mix
- Bordeaux Mixture
- DIY Bordeaux Fungicide Recipe: Tips For Making Bordeaux Fungicide
- Bordeaux Fungicide Recipe
- Making Bordeaux Fungicide
- How to Make Bordeaux Fungicide in Small Amounts
- Preparation of Bordeaux mixture
- What is Bordeaux mixture?
- When to use Bordeaux mixture
- Diseases and Bordeaux mixture
- Read also on diseases and parasites
- Preparing Tank-mix Bordeaux Mixture
- How to Manage Pests
- Pesticide Information
- How To Make Your Own Bordeaux Mixture
- Uses of Copper Compounds: Copper Sulphate’s Role in Agriculture
- Preparation of Bordeaux and Burgundy Mixtures on the Farm
- Dissolving Copper Sulphate
- Preparation of Bordeaux Mixture
- Preparation of a 1% Burgundy Mixture
- Correction of Copper Deficiency in Soils
- Correction of Copper Deficiency in Animals
- Stimulation of Growth for Fattening Pigs and Broiler Chickens
Easy to mix
One of the great advantages of Bordeaux spray is that it can be inexpensively and safely mixed at home with two easily obtainable ingredients, copper sulphate and slaked lime. Many nurseries sell copper sulphate as bluestone while slaked lime is widely available as Limil.
Quite small quantities of ingredients will make many litres of spray. This is just as well as plants should be thoroughly sprayed to the point of runoff.
Bordeaux spray is mixed in two stages. To make a 1% solution dissolve 100 grams of copper sulphate in 5 litres of water in one bucket and 100 grams of limil in 5 litres of water in another bucket. Warm water will help ingredients dissolve more easily. Then, while stirring, pour the lime mixture into the copper mixture. A cloudy blue-coloured liquid results.
The key to successful spraying is straining the resulting mixture through muslin cloth to remove larger solid particles that can block spray nozzles. For best results strain twice. First strain through two thicknesses of muslin cloth when pouring the lime mixture into the copper solution. Rinse the muslin in cold water, fold it over the top of the garden sprayer and pour the complete lime/copper mixture into the sprayer. Remember to continuously stir while preparing and agitate while spraying as the mixture can quickly settle out. It is best used within 24 hours of mixing.
Step by step instructions to mix 20 litres of 1% solution
The discovery of Bordeaux spray, named for the famous French wine region, like many of the most useful scientific discoveries was an accident.
In the latter half of the 19th century it was common practice to deter pilfering of ripening grapes by spraying vines with a mixture of copper and lime. The cloudy residue, which created an unattractive appearance and left an unpleasant taste, was only sprayed on the first few rows of vines nearest the roadside, those within reach of hungry passersby. Following an outbreak of downy mildew in the early 1880s it was discovered that vines sprayed with the copper mixture were largely unaffected by the fungus. Subsequent trials led to Bordeaux spray, as it became known, becoming the world’s first fungicide.
Its low mammalian toxicity and topical mode of action make it a safe spray that is accepted under various organic registration regimes. It is still in wide use today and, in fact, remains a most useful tool for both conventional and organic growers of a wide range of fruit and vegetables.
SERIES 17 | Episode 12
Isn’t it amazing, that two of the most effective of the old fashioned fungicides you can make yourself at home and they work brilliantly.
These fungicidal sprays were developed in France, originally as a means of controlling problems of mildew on grape vines. They are also useful as relatively safe means of controlling leafcurl disease of peach and nectarine trees, brown rot of stonefruit, raspberry leaf rust and other fungal diseases of plants.
Gloves, face protection and other protective clothing should be worn by anyone with a sensitive skin or allergy both during the mixing and spraying operations. Keep ingredients and the mixtures secure, labelled and out of reach of children.
The recipes are full strength and must never be used on plants when in leaf as foliage burn can occur. The sprays are used at leaf fall in late autumn or early winter and again just before the leaves appear in late winter or spring, usually in late July and early August.
- Dissolve 100 gram of builders’ (hydrated) lime in half a standard (plastic) bucket of water. (About 5 litres).
- Dissolve 100 grams copper sulphate (available at garden centres) in a separate half bucket of water.
- Keeping the lime mixture agitated to prevent settling, pour it steadily into the half bucket of dissolved copper sulphate.
- If necessary add enough extra water to make up a total of 10 litres. This is Bordeaux mixture. It is at its most effective strength when freshly mixed so must be used immediately or within a couple of days.
- It is sprayed to completely cover the main (bare) branches of peach, nectarine and other stone fruit trees to help control leaf curl and brown rot disease. It is also sprayed over raspberry canes in late July for control of raspberry rust.
- Bordeaux mixture colours the sprayed plants blue. The spray can withstand light rain. However a disadvantage with this mixture is that it tends to quickly settle so must be constantly agitated during spraying operations. The lime content also tends to easily block the fine nozzles of sprayers.
This is virtually the same except that lime is replaced by washing soda (cheaply available at supermarkets in 1kg packets as a water softener).
The amounts are the same, as is the method of mixing. Always use non-metal buckets – standard 10 litre plastic buckets are ideal. If the water is slightly warm the washing soda and the copper sulphate dissolve more rapidly.
Slowly pour half a bucket of (100 grams) dissolved washing soda into half a bucket of (100 grams) dissolved copper sulphate and add more water if necessary to make up 10 litres.
The advantage of Burgundy mixture is that it does not block sprayer nozzles. It is also a little stronger and must never be used on plants in leaf.
(DISCLAIMER: BORDEAUX AND BURGUNDY MIXTURES HAVE BEEN SAFELY USED FOR MANY YEARS. THESE RECIPES AND THE WAY THEY ARE MIXED AND USED ARE SUGGESTED HERE AS A MATTER OF GENERAL INTEREST AND INFORMATION. WE ACCEPT NO RESPONSIBILITY FOR HOW THEY ARE MIXED, USED OR STORED OR ANY ADVERSE OR OTHER EFFECTS THEY MAY HAVE ON PEOPLE, PLANTS OR THE ENVIRONMENT.)
DIY Bordeaux Fungicide Recipe: Tips For Making Bordeaux Fungicide
Bordeaux is a dormant season spray that is useful to combat fungal diseases and certain bacterial issues. It is a combination of copper sulfate, lime and water. You can purchase a prepared mixture or make your own Bordeaux fungicide preparation as you need it.
Fall and winter are the best times to protect plants from spring fungal problems with homemade Bordeaux mixture. Issues such as downy and powdery mildew, and black spot can all be controlled with proper application. Fire blight of pear and apple are bacterial diseases that can also be prevented with the spray.
Bordeaux Fungicide Recipe
All the ingredients are available at garden centers, and the recipe that follows will help with making Bordeaux fungicide. This recipe is a simple ratio formula that most home growers can easily master.
Copper fungicide is readily available as a concentrated or ready to use preparation. The homemade recipe for Bordeaux mix is 10-10-100, with the first number representing copper sulfate, the second is dry hydrated lime and the third water.
Bordeaux fungicide preparation weathers better on trees than many of the other fixed copper fungicides. The mixture does leave a blue-green stain on plants, so it is best to keep it off any that are near the home or fencing. This recipe is not compatible with pesticide and can be corrosive.
Making Bordeaux Fungicide
Hydrated lime, or slaked lime, is calcium hydroxide and is used to make plaster among other things. You need to soak the hydrated/slaked lime before using it (dissolve it at 1 pound slaked lime per gallon of water).
You can start your Bordeaux fungicide preparation with a slurry of sorts. Use 1 pound copper in 1 gallon of water and mix it in a glass jar that you can seal.
The lime should be handled with care. Use a dust mask to avoid inhaling the fine particles when making Bordeaux fungicide. Mix 1 pound lime into 1 gallon of water and let it stand for at least two hours. This allows you to make a quick solution of Bordeaux.
Fill a bucket with 2 gallons water and add 1 quart of the copper solution. Mix the copper slowly into the water and then finally add the lime. Stir as you add 1 quart of the lime. The mixture is ready to use.
How to Make Bordeaux Fungicide in Small Amounts
For spraying in small amounts, prepare as above but only mix 1 gallon of water, 3 1/3 tablespoons of copper sulfate and 10 tablespoons of hydrated lime. Agitate the mixture thoroughly before you spray.
Whichever type you use, make sure the lime is from this season. The homemade Bordeaux mixture needs to be used the day you prepare it. Make sure you rinse the Bordeaux fungicide preparation out of your sprayer with plenty of water, since it is corrosive.
Preparation of Bordeaux mixture
About Bordeaux mixture
In the year 1761, Schulthez first used the copper sulphate for the seed treatment of Wheat diseases. Later on Prevost termed the copper as fungicide. In 1882, Millardet in France (Bordeaux University) accidentally observed the efficacy of the copper sulphate against the downy mildew of grapes caused by Plasmopara viticola. When copper sulphate was mixed with lime suspension, it effectively checked the disease incidence. The mixture of copper sulphate and lime was named as “Bouillie Bordelaise” (Bordeaux Mixture).
The original formula developed by Millardet contains 5 lbs of CuSO4 + 5lbs of lime + 50 gallons of water. The chemistry of Bordeaux mixture is complex and the suggested reaction is: CuSO 4 + Ca (OH) 2 = Cu(OH) 2 + CaSO 4
The ultimate mixture contains a gelatinous precipitate of copper hydroxide and calcium sulphate, which is usually sky blue in colour. Cupric hrdroxide is the active principle and is toxic to fungal spores.
Bordeaux mixture is generally accepted even in organic cultivation. It is easy to prepare and can be locally prepared by farmers themselves.
Preparation of 1 % Bordeaux Mixture
- Copper sulphate powder – one kg
- Lime – 1 kg
- Water – 100 litres
One kg of copper sulphate powder is dissolved in 50 litres of water. Similarly, 1 kg of lime is powdered and dissolved in another 50 litres of water. Then copper sulphate solution is slowly added to lime solution with constant stirring or alternatively, both the solutions may be poured simultaneously to a third contained and mixed well.
Preparation of 0.5% Bordeaux mixture is same as above but reducing the copper sulphate and lime half of the amount but keeping water same as 1% mixture preparation.
In general, 1% Bordeaux mixture is applied to hardy plant parts such as roots, stem and 0.5% of mixture is applied on leaf/foliage.
Tests to determine pH of the prepared Bordeaux mixture
The ratio of copper sulphate to lime solution determines the pH of the mixture. The mixture prepared in the above said ratio gives neutral or alkaline mixture. If the quality of the used materials is inferior, the mixture may become acidic. If the mixture is acidic, it contains free copper which is highly phytotoxic resulting in scorching of the plants. Therefore, it is highly essential to test the presence of free copper in the mixture before applied.
There are several methods to test the neutrality of the mixture, which are indicated below:
- Field Test: Dip a well polished knife or a sickle in the mixture for few minutes. If reddish deposit appears on the knife/sickle, it indicates the acidic nature of the mixture.
- Litmus paper test: The colour of blue litmus paper must not change when dipped in the mixture.
- pH paper test : If the paper is dipped in the mixture, it should show neutral pH.
- Chemical test : Add a few drops of the mixture into a test tube containing 5 ml of 10% potassium ferrocyanide. If red precipitate appears, it indicates the acidic nature of the mixture.
If the prepared mixture is in the acidic range, it can be brought to neutral or near alkaline condition by adding some more lime solution into the mixture.
The following precautions are needed during preparation and application of Bordeaux mixture.
- The solution should be prepared in earthen or wooden or plastic vessels. Avoid using metal containers for the preparation, as it is corrosive to metallic vessels.
- Always copper sulphate solution should be added to the lime solution, reverse the addition leads to precipitation of copper and resulted suspension is least toxic.
- Bordeaux mixture should be prepared fresh every time before spraying. In case, the mixture has to be stored for a short time or a day, jaggery can be added at the rate of 100kg/100 litres of the mixture.
- Bordeaux mixture is sometimes phytotoxic to apples, peaches, new shoots/leaf.
Advantages of Bordeaux mixture
- Very easy and can prepared by farmers themselves.
- Can act as fungicide, bactericide and algaecide.
- Applicable to tomato, potato, chilli, other vegetables, fruits (orange, lime, lemon), beetel vine, ginger, flower and ornamental plant diseases such as foot rot, stem rot, leaf spot, leaf blight, anthracnose, canker, damping off, black spot, downy mildew, late and early blight etc.
- The chemicals required for this is copper sulphate and lime which is easily available in the market.
- All the diseases controlled by copper based fungicides such as leaf spot, blight diseases can be controlled by this.
- It is less toxic to human as compare to other commercial fungicides.
- It cannot be keep for long periods (More than 2 days after preparation).
- It cannot be applied during the cold and cloudy weather, as it causes phytotoxicity to plants.
- It cannot be applied to apple, maize and some of the dwarf rice varieties.
Bordeaux Paste consists of same constituents as that of Bordeaux mixture, but it is in the form of a paste as the quantity of water used is too little. It is nothing but 10 per cent Bordeaux mixture and is prepared by mixing 1 kg of copper sulphate and 1 kg of lime in 10 litres of water. The method of mixing solution is similar to that of Bordeaux mixture. It is a wound dresser and used to protect the wounded portions, cut ends of trees etc., against the infection by fungal pathogens.
Bordeaux paint consists of 100g copper sulphate with 200g lime in 300ml water. It is a wound dresser and used to protect the wounded portions, cut ends of trees etc., against the infection by fungal pathogens.
Source : CAU Farm magazine Vol 6. No. 3
Bordeaux mixture is an effective fungus treatment authorized for use in organic farming.
It is widely used in the garden to treat plants, vegetables and fruit trees.
Following recommended doses and uses for this product is nonetheless necessary to avoid contaminating nature.
Basic Bordeaux mixture facts
Purpose and use – fungicide, algicide
Content – water, copper sulfate and lime
Most relevant plants – grape vine, fruit trees, potatoes, tomatoes
What is Bordeaux mixture?
It is a blue-colored fungicide prepared from copper and lime.
It is usually used sprayed, and helps fight most types of fungal diseases. Fungal diseases are due to mushrooms and fungus. Bordeaux mixture is often used against downy mildew, scab, fruit leaf curl, canker or European brown rot.
Recommended dosage is maximum ⅓ to ⅔ oz. (10 to 20 g) for 1 quart (1 liter) water.
When to use Bordeaux mixture
The first Bordeaux mixture treatment should be applied at the end of winter. Doing this during the winter deep cleaning is a good time to eliminate mushrooms that may have overwintered among plants.
It is often used in spring when diseases develop.
- Indeed, moisture and warmth are the two conditions that trigger fungus growth.
Bordeaux mixture is also used in fall after leaves have fallen off trees.
- Spraying at this moment helps avoid that any given disease overwinters in the garden.
- It is important to destroy any sick leaves that have already fallen to the ground.
- Spray Bordeaux mixture on the entire tree: branches, trunk, and eventually neighboring areas.
Preventive use is effective to defend against fungal diseases (mushrooms).
Most diseases targeted are:
- Apple scab
- Peach leaf curl
- Knot or canker
- Rotting fruit, European brown rot
It is almost useless to spray Bordeaux mix when the fungus has already appeared, because its main purpose is preventive.
But it can be argued that spraying when the disease has appeared can nonetheless contain its spread.
Diseases and Bordeaux mixture
Fruit trees are treated preventively in fall when the leaves fall.
The treatment is repeated at the end of winter after pruning to protect the fresh wounds from contamination by fungus.
- Begin with picking up dead leaves and burning them before spraying Bordeaux mixture.
- This is best done at the end of winter or at the very beginning of spring, just before the first buds appear.
- In both cases, it is highly recommended to renew this step 2 to 3 times at a two-week interval.
- Read also: How to treat rotting fruit, European brown rot
Potato, tomato and strawberry plants
Starting in May, spray once every two weeks.
This treatment is a necessity because these vegetables are the most vulnerable to downy mildew, and contamination would compromise the harvest.
- Stop treating a few weeks before harvest.
- Read also: growing and caring for potatoes, tomatoes, strawberry plants.
- Grape vines are very vulnerable to mildew and deserve to be treated every year in spring and in fall.
That is where the mixture’s name comes from: “Bordeaux”.
- Start treating in April, continue until end of July, spraying Bordeaux mixture every two weeks and after every heavy rain.
- Read also: growing and caring for grapevines, and pruning grapevines.
Read also on diseases and parasites
- Fighting aphids
- Fighting caterpillars
- How to treat downy mildew.
- How to treat apple scab
- How to treat peach leaf curl
- How to treat canker.
Even though using Bordeaux mix is authorized in organic farming, it is strongly recommended to not increase prescribed doses.
Also avoid using Bordeaux mixture too often, or in itself it will lead to contamination.
Preparing Tank-mix Bordeaux Mixture
Bordeaux mixture is an outstanding fungicide and bactericide for controlling some diseases of tree fruits, small fruits, and ornamentals. Bordeaux mixture’s ability to weather fall, winter, and spring rains and adhere to plants is a valuable characteristic. Probably the most effective bordeaux solution is made the “old-fashioned” way by preparing “stock” solutions of lime and copper sulfate that are later mixed by pouring into water in the spray tank. Many growers, however, do not have the proper containers or the time required to make bordeaux this way. Tank-mix bordeaux is an excellent fungicide and bactericide that requires little time and no special containers for preparation.
There are many bordeaux formulas to control plant diseases. Each formula recommended is the result of research on a specific crop disease. For example, bordeaux 8-8-100 is recommended to control peach Coryneum blight, and bordeaux 12-12-100 to control dead bud of cherry. Because bordeaux colors plants blue and may discolor house paint, it is not used as often on ornamental plants as it is on agricultural plants. Applying bordeaux in hot weather can cause leaves to yellow and drop.
Bordeaux formulas are stated as three hyphenated numbers: 8-8-100. The first number refers to the pounds of bluestone (copper sulfate), the second number to the pounds of spray (hydrated) lime, and the last number to the gallons of water to be used. Thus, an 8-8-100 bordeaux contains 8 lb copper sulfate, 8 lb spray lime, and 100 gal water.
Prepare Small Amounts of Bordeaux Spray Using these Conversions.
If 100-gallon formula requires
Use for 1 gallon
1 lb copper sulfate
1 tsp copper sulfate
1 lb spray lime
1 tsp spray lime
Thus a 1-gallon mixture of 8-8-100 bordeaux will contain 8 tsp copper sulfate, 8 tsp spray lime, and 1 gal water. (Mixing may go faster if you measure in tablespoons; 1 Tbsp = 3 tsp.)
Ready-mix bordeaux preparations are available but usually are less effective than the tank-mix or “homemade” bordeaux.
Copper sulfate Use only powdered copper sulfate (bluestone or blue vitriol), often referred to as copper sulfate “snow” because it is finely ground and dissolves relatively quickly in water, to prepare tank-mix bordeaux. Ordinary lump copper sulfate is not satisfactory. Store copper sulfate snow in a dry place. Moist snow becomes lumpy and is difficult to work through the screen into the tank. Use copper sulfate registered to make bordeaux mixture.
Lime To prepare tank-mix bordeaux, use only good quality hydrated lime (calcium hydroxide). The hydrated lime should be fresh, that is, not carbonated by prolonged exposure to air. Hydrated lime is stable and usually is readily available under several trade names. Magnesium lime, a mixture of Ca(OH)2 and Mg(OH)2, may also be used.
Slaking produces enough heat to boil the water, so be careful about how much lime is exposed to the water at any one time to avoid splashing.
Slaked lime makes an excellent suspension and may be used to prepare tank-mix bordeaux mixture, but slaking requires more time, effort, and containers than using prepared hydrated lime.
Tank-mixing the Bordeaux
The copper sulfate should be in solution and the lime should be in suspension before they are mixed. If that is so, it doesn’t matter whether you pour the lime suspension into the copper solution or vice versa. Both methods are commonly used. If neither is in solution:
- Start water flowing into the spray tank.
- When the tank is about a third full and the mechanical agitator is on, start washing the copper sulfate snow into the tank through a screen with water from the supply hose. A wooden spoon or paddle is often helpful in working the snow through the screen. Don’t hurry the snow through the screen—give the copper sulfate time to go into solution in the tank.
- By the time the tank is two-thirds full, all of the snow (copper sulfate) should be in the tank. Then use the water supply hose to wash the lime through the screen into the copper sulfate solution in the tank. Again, a wooden spoon or paddle will be useful in working the lime through the screen into the tank. The lime should be as diluted as possible before it meets the copper sulfate solution in the tank. Use lots of water to wash the lime through the screen.
- Start the mechanical agitator in the tank before you put the copper sulfate snow in; keep the agitator going as you add the lime and until you apply the spray. A bypass agitator system is usually not adequate to tank-mix a bordeaux.
- Apply bordeaux the day you make it—it deteriorates on standing. If it has to be left overnight before use, add 1/8 oz of sugar for each pound of copper in the tank; for example, for 100 gal of 8-8-100 bordeaux, add 1 oz sugar to the spray mixture.
How to Manage Pests
In this Guideline:
Bordeaux mixture—a combination of copper sulfate, lime, and water—is an effective fungicide and bactericide that has been used for decades to control diseases of fruit and nut trees, vine fruits, and ornamental plants. These natural minerals, when mixed in the correct order, provide long-lasting protection to plants against diseases.
The ability of Bordeaux mixture to adhere to plants in rainy weather makes it an excellent choice for a winter fungicide. Applying Bordeaux after trees break dormancy generally isn’t recommended, because it can injure leaves.
Among Bordeaux’s many uses are applications in fall and winter to manage:
- Fire blight on pears and apples;
- Leaf curl and shot hole on peaches and nectarines;
- Downy mildew and powdery mildew on grapes;
- Peacock spot on olives;
- Walnut blight on walnut; and
- Black spot on roses.
Because Bordeaux can leave a blue-green discoloration on plants or painted surfaces, use it on dormant, deciduous plants that are away from buildings and fences.
Fixed copper fungicide sprays (e.g. tribasic copper sulfate, copper oxychloride sulfate, and cupric hydroxide) also control many of the same disease-causing organisms as Bordeaux mixture. Although fixed copper sprays are much easier to prepare and don’t stain surfaces, they don’t withstand winter rains as successfully. However, they are the most effective and best choice to use in spring after trees begin to show new growth.
With all Bordeaux and fixed copper sprays, thorough coverage is essential to give plants the desired protection from disease-causing pathogens. Advantages and disadvantages of fixed copper and Bordeaux sprays are compared in Table 1.
Bordeaux mixture is commercially available in premixed packages, but freshly made Bordeaux sticks and weathers better on trees.
|Characteristic||Fixed coppers||Bordeaux mixture|
|Ease of storage||Store dry||Store in stock solutions or dry|
|Effectiveness||Less effective, less persistent||Highly effective and long lasting|
|Environmental impact||Less active for less time, seldom stains||Longer lasting, more active, stains surfaces|
|Phytotoxicity||Safe for most plants and tender growth||High pH, leaves a salty deposit, more phytotoxic|
|Compatibility||Compatible with many pesticides||Not compatible with most pesticides|
|Ease of preparation||Easily prepared, less safety equipment||Takes longer, requires more knowledge to prepare, safety equipment required|
|Corrosiveness||Less corrosive spray mixture||Corrosive spray mixture|
1Effectiveness is a function of coverage, timing, and concentration.
THE BORDEAUX FORMULA
Although there are many formulas for preparing Bordeaux mixture, generally a ratio of 10-10-100 works well for many disease-causing pathogens. The three hyphenated numbers represent the amount of each material to add.
The first number refers to pounds of copper sulfate, the second to pounds of dry hydrated lime, and the third to the total gallons of water. Thus a 10-10-100 Bordeaux mixture would be comprised of 10 pounds of copper sulfate, 10 pounds of lime, and 100 gallons of water.
A more manageable amount for the home gardener would be a 1-gallon mixture of 10-10-100 Bordeaux, which would contain 1/10th of a pound of each of the dry ingredients, which would be 3 1/3 tablespoons of copper sulfate and 10 tablespoons of dry hydrated lime in 1 gallon of water. You can purchase copper sulfate and hydrated lime at most garden centers.
Powdered copper sulfate, often referred to as “bluestone,” is a finely ground material that dissolves relatively quickly in warm water. Ordinary, lump copper sulfate isn’t satisfactory, because it is slow to mix into the solution. Store copper sulfate in a dry place. If it gets moist, it becomes lumpy and difficult to work with. Fixed copper fungicides shouldn’t be used in making up a Bordeaux mixture.
You can use either dry hydrated lime or slaked lime to prepare Bordeaux. The most important point is to use fresh lime. Don’t use lime from last season, and purchase only what you can use in the current season.
Use only good quality hydrated lime (calcium hydroxide). The hydrated lime should be fresh and not carbonated by prolonged exposure to air. Hydrated lime is a dry product commonly used to make plaster and is readily available under several trade names. When mixing lime, protect your eyes, nose, and mouth by using a dust- and mist-filtering respirator.
Slaked lime is prepared by adding “quick” (hot, burned) lime (calcium oxide) to water to produce calcium hydroxide. Slaking quick lime in water can produce heat sufficient to boil the water, so regulate the amount of lime you add to the water at any one time, so the mixture doesn’t splash. Wear goggles or safety glasses to protect your eyes and stir the mix with a wooden stick while adding the lime to the water. The slaking chemical reaction takes 1/2 to 2 hours, so prepare the lime mixture before you plan to spray.
To make slaked lime add 1 pound of quick lime per gallon of water. This results in a mixture the consistency of milk. Slaked lime makes a superior suspension, but it requires more time, effort, and containers than prepared hydrated lime. If using slaked lime, follow the procedures in the Stock Solutions section below.
MAKING THE BORDEAUX MIXTURE
The effectiveness of a Bordeaux spray depends almost entirely on following the correct procedure for mixing. You can prepare Bordeaux directly in a spray tank equipped with an agitator, or if you don’t have a power sprayer, you can prepare smaller amounts for use in a hand sprayer. If you use a hand sprayer, you’ll first need to mix up stock solutions of lime and copper sulfate as described below. No matter how you mix the ingredients, you’ll need to use the spray solution soon after you prepare it, since the mixture will deteriorate upon standing.
When applying Bordeaux, be sure to wear protective clothing, including goggles, because the spray deposit is corrosive, can permanently stain clothing, and is difficult to wash off.
If both materials are still in dry form you’ll need to use a tank with an agitator. Follow these steps to make a tank mix of 10-10-100 formula. Use a ratio of 1 gallon of water, 3 1/3 tablespoons of copper sulfate, and 10 tablespoons of hydrated lime for each gallon of spray mixed.
Start flowing water into the spray tank. When you have put about 1/3 of the water into the tank and the mechanical agitator is in operation, start washing the copper sulfate into the tank through a screen with water from the supply hose. A wooden paddle is useful for working the copper sulfate through the screen. Don’t hurry it through the screen; give the copper sulfate time to get into solution in the tank. By the time 2/3 of the water is in the tank, all of the copper sulfate should be mixed in.
In a plastic bucket or other corrosion-resistant container, mix the dry hydrated lime into a portion of the remaining water. Then slowly pour the lime suspension into the copper sulfate and water mixture. Finish filling the tank to the correct volume of water. You can include the rinse water from the mixing container.
Continue agitating the tank while adding the ingredients and applying the spray. A bypass agitator system usually isn’t adequate for preparing a tank mix of Bordeaux.
Apply the Bordeaux the same day you prepare it. After you have used up the mixture, immediately rinse the equipment at least three times, since the mixture is highly corrosive to metal tanks and pump parts. Add a small amount of vinegar to the rinse water to neutralize any leftover residue.
The old-fashioned way of making a Bordeaux mixture is to prepare “stock” solutions of lime and copper sulfate that you later mix by pouring them into water in a sprayer. This method also works best for making small quantities of Bordeaux.
Using a plastic bucket, dissolve 1 pound of copper sulfate into 1 gallon of warm water. You can store this solution indefinitely in a stoppered, glass container.
For the lime, use the slaked lime suspension described above or mix a solution of 1 pound of fresh hydrated lime in 1 gallon of water. This mixture needs to stand for about 2 hours before use. You can store the lime mixture indefinitely as well in a stoppered container. Preparing a stock mixture of lime eliminates the need to obtain fresh hydrated lime each time you prepare a Bordeaux mixture.
Be sure to clearly label both stock solutions and store them where children can’t get into them, since these materials, especially the copper sulfate, are very toxic and corrosive.
To make 2 1/2 gallons of a 10-10-100 Bordeaux mixture, measure 2 gallons of water into a strong plastic bucket. Shake the copper sulfate solution vigorously before adding 1 quart of it to the 2 gallons of fresh water. Always add the copper to the spray water before adding the lime. Shake the lime mixture, and add 1 quart to the 2 gallons of water. Keep stirring the spray water mixture while adding the copper and the lime and continue stirring or shaking for several minutes before pouring it into the sprayer. The mixture now is ready to use.
Be sure to constantly shake the sprayer while using it to avoid clogging. Read the label directions carefully on the copper sulfate regarding the proper protective equipment to wear when preparing the stock solutions and when spraying. Bordeaux performs best if nothing is added to the prepared mix described above.
This formulation of Bordeaux mixture will be adequate for practically all home-garden, disease-protection needs. If you wish to maintain Bordeaux mixture on a tree throughout the entire winter rainy period, you can reapply the spray, or use a slightly stronger mixture—1 1/2 quarts of each stock solution to 2 gallons of water. In spring when buds are opening or on sensitive plants, use a slightly weaker mixture—1 pint of each solution to 2 gallons of water—or use a fixed copper spray.
WARNING ON THE USE OF PESTICIDES
Pscheidt, J. W., and C. M. Ocamb, eds. 1999. Pacific Northwest Plant Disease Control Handbook. Corvallis: Oregon State Univ.
Authors: J. C. Broome, Plant Pathology, UC Davis; and D. R. Donaldson, UC Cooperative Extension emeritus, Napa Co.
Produced by UC Statewide IPM Program, University of California, Davis, CA 95616
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How To Make Your Own Bordeaux Mixture
Commonly used as a control of potato blight Bordeaux mixture can also be used to treat a range of other fungal diseases including rusts, mildews, cankers & leaf moulds. Bordeaux mixture has been around for many years and been used by gardeners safely on a wide range of ornamental plants, fruits and vegetables
Bordeaux Mixture on Tomatoes Bordeaux Mixutre on Grapes Making Bordeaux mixture
What may not be well known is that Bordeaux mixture is made up of some very basic ingredients and these are all readily available to many gardeners. This means to you too can make your own Bordeaux mixture at home to apply to plants when needed. Just remember that Bordeaux mixture is a preventative rather than a cure and therefore it should be applied to plants before sign of an infestation are noticed
How to make your own Bordeaux mixture:
Diluted the hydrated Lime (or builders lime – i.e. the lime used in mixing cement) in water. Add 100 grams of lime to 5 litres of water
Next diluted the copper sulphate (also known as moss killer or Sulphate or Iron). Add 100 grams of copper sulphate to approx.5 litres of water
Mix the lime and water together until the lime has fully dissolved into the water and gradually pour the 5 litre mixture into the 5 litres of diluted copper sulphate and water
Give all a quick mix and then voila! You have 10 litres of ready to used Bordeaux mixture. The process could not be simpler and the ingredients more basic
Just note; this mixture works best directly after being made so you should use it as soon as possible. Also you can reduce the measurements to make smaller quantities of the Bordeaux mixture
Apply to Foliage before signs of attack, With potatoes you should start applying in April. Fungal attacks are more common in warm and damp weather. Apply to both the top and underside of the foliage ensuring a good covering. Reapply the mixture regularly over the season
You can use a knapsack sprayer to apply bureaux mixture, just make sure that you continue to shake and mixture the contents regularly to prevent the lime from settling to the bottom. Also you will need to clean the nozzle of the sprayer regularly to prevent it from clogging up
Uses of Copper Compounds: Copper Sulphate’s Role in Agriculture
Copper sulphate has many agricultural uses (see Table A) but the following are the more important ones:
- Preparation of Bordeaux and Burgundy mixtures on the farm
- Control of fungus diseases
- Correction of copper deficiency in soils
- Correction of copper deficiency in animals
- Stimulation of growth for fattening pigs and broiler chickens
- A molluscicide for the destruction of slugs and snails, particularly the snail host of the liver fluke
Preparation of Bordeaux and Burgundy Mixtures on the Farm
Because of their importance to farmers, instructions concerning the dissolving of copper sulphate and the preparation of both Bordeaux and Burgundy mixtures have been included in the text.
Dissolving Copper Sulphate
Iron or galvanised vessels must not be used for the preparation of copper sulphate solutions. Plastic vessels, now freely available, are light and very convenient. To make a strong solution, hang a jute sack of copper sulphate so that the bottom of it dips a few inches only in the water. The copper sulphate will dissolve overnight. Copper sulphate dissolves in cold water to the extent of about 3 kg per 10 litres. If more than this is placed in the sack described above, then a saturated solution will be obtained and it may be used without serious error on the basis that it contains 3 kg copper sulphate per 10 litres.
Preparation of Bordeaux Mixture
Bordeaux mixture is prepared in various strengths from copper sulphate, hydrated lime (calcium hydroxide) and water. The conventional method of describing its composition is to give the weight of copper sulphate, the weight of hydrated lime and the volume of water in that order. The percentage of the weight of copper sulphate to the weight of water employed determines the concentration of the Bordeaux mixture. Thus a 1% Bordeaux mixture, which is the normal, would have the formula 1 :1:100the first 1 representing 1 kg copper sulphate, the second representing 1 kg hydrated lime, and the 100 representing 100 litres (100 kg) water. As copper sulphate contains 25% copper metal, the copper content of a 1% Bordeaux mixture would be 0-25 % copper. The quantity of lime used can be reduced considerably. Actually 1 kg copper sulphate 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, it is safest not to exceed a ratio of 2:1. i.e. a 1:0.5:100 mixture.
In preparing Bordeaux mixture, the copper sulphate is dissolved in half the required amount of water in a wooden or plastic vessel. The hydrated lime is mixed with the balance of the water in another vessel. The two “solutions” are then poured together through a strainer into a third vessel or spray tank.
Preparation of a 1% Burgundy Mixture
Dissolve separately 1 kg copper sulphate in 50 litres water and 1.25 kg washing soda (or 0.475 kg soda ash) in 50 litres water and slowly add the soda solution to the copper sulphate solution with stirring. Control of fungus diseases
Bordeaux and Burgundy mixtures have been found effective in controlling a whole host of fungus diseases of plants. Normally a 0.5 % to 1 % Bordeaux or Burgundy mixture applied at 2 to 3 week intervals suffices to control most copper-susceptible fungi.
Generally once the fungus spores have alighted on the host plant and penetrated the tissues it is difficult to control them. The principle of control must in most cases depend on protection, ie preventing the fungus spores from entering the host tissues. Copper fungicides are noted for their tenacity and for this reason are much to be preferred in areas of high rainfall.
The simplest method of control is to apply a protective coating of Bordeaux or Burgundy mixture (or other copper fungicide) to the susceptible parts of the plant, so that spores alighting on them come in contact with the protective film of copper and are killed instantly. It is thus important to remember that the first spraying must ideally be made just before the disease is expected and continued at intervals throughout the susceptible period. For this reason it is important to take advantage of the early warning schemes which are in operation to ensure greater accuracy of the timing of the first spraying.
It must also be remembered that fungi are plants and that control measures that will kill them may not always leave the host plant unaffected. The use of too concentrated a fungicide mixture must therefore be guarded against, particularly for the early sprays.
Copper fungicides have been reported effective against numerous plant diseases. A list, by no means exhaustive, of some 300 diseases that have been found amenable to control by copper fungicides, appears in Table B.
Correction of Copper Deficiency in Soils
Where copper deficiency has been confirmed by soil analysis or field diagnosis, whether in plants or animals, it can be corrected very simply either by applying 50 kg copper sulphate per hectare in the form of a fertiliser before sowing or by spraying the foliage of the young cereal plants, when they are about 150 mm high, with 750 grams copper sulphate (dissolved in from 400 to 2,000 litres water) per hectare. The soil application has generally given the better results and has the advantage that it may have a residual effect for more than ten years. The foliar application has to be given annually to each crop. An alternative is to add a copper containing slag (normally about 1% to 2 % copper) at a rate of a tonne to the hectare.
Correction of Copper Deficiency in Animals
A method of correcting copper deficiency in livestock is to treat the soil on which animals graze. For example, in Australia and New Zealand swayback in lambs is being prevented by top dressing copper deficient pastures with 5 to 10 kg copper sulphate per hectare some time before lambing begins.
Other methods include drenching periodically with a copper sulphate solution; incorporating copper sulphate in salt and other animal licks; or by what is probably the most general method, incorporating copper sulphate along with other minerals and vitamins in the form of carefully blended supplements in the feeding stuffs.
Stimulation of Growth for Fattening Pigs and Broiler Chickens
The inclusion of up to as much as 0.1% copper sulphate in the diet of bacon and pork pigs and broiler chickens stimulates appetite and produces increased growth rate with a marked improvement in feed conversion.
A molluscicide for the destruction of slugs and snails, particularly the snail host of the liver fluke. All likely habitats of the liver fluke snail should be treated with copper sulphate at the rate of 25 kg to the hectare at least twice a year in June and August (northern hemisphere) or December and February (southern hemisphere).