Bordeaux mixture, which is frequently used in gardening, is a copper-based fungicide. Sold under different brands, it is available in powder or micro-granular form. Gardeners use it as a preventative treatment in the spring, once the buds start appearing. However, precautions must be taken when applying the product as Bordeaux mixture used in excess can be toxic to plants and pollute the soil.

Originally, Bordeaux mixture was used to treat mildew in vineyards. This product helps to fight off many diseases such as apple and pear scab, potato and tomato late blight, gummosis in stone fruit trees and bacterial canker of pear and apple trees . Bordeaux mixture is used to overcome some bacterial diseases like bacteriosis.

Bordeaux mixture, en effective recipe

Bordeaux mixture was discovered accidentally by the winemakers of Bordeaux who used this product to fight against thieves, making the fruit inedible. Bordeaux mixture is a traditional recipe that has been used for the treatment of fungi for centuries. It is a blue-coloured fungicide based on copper sulphate and lime, of which the doses respectively are 0.163 drams per fluid ounce and 0.325 drams per fluid ounce (10 grams/ Liter, 20 grams/ Liter). The copper contained in Bordeaux mixture enhances lignification and plant resistance to frost. After applying the product, the fruits are more resistant to decay and bacteria. Bordeaux mixture also allows rapid healing of the branches after pruning.

Using Bordeaux mixture

The powder or micro-granules in bags are to be diluted in water to produce Bordeaux mixture. The resulting solution, of blue tint, is applied by spray on plants requiring treatment. Preventive treatment of fruit trees such as plum, apricot and peach is carried out in February, in dry weather, and before flowering. Strawberry plants, vines, tomatoes and potatoes are to be sprayed in May, with a renewed applications of Bordeaux mixture every two weeks. The plum tree, the apple tree, the apricot tree and the peach tree are to be treated in the fall after leaf drop. The use of Bordeaux mixture in organic agriculture should not exceed the copper concentration of 5.354 pounds per acre (6 kilograms per hectare), an appropriate annual limit.

Precautions for use of Bordeaux mixture

Misusing Bordeaux mixture is toxic to plants. The leaves wither when exposed to copper sulphate. Given that copper cannot be rapidly leached into the ground, the metal can reach concentrations of 1.4 grain per pound of soil (200 mg / kg), a rate disproportionate to the threshold of 0.014 to 0.420 grain/ lb (2 to 60 mg/ kg). It is therefore advisable to respect the dosage levels by avoiding spraying during periods of high heat.

Stone fruit trees cannot be treated during their flowering period. The application of Bordeaux mixture at this time may lead to coulure. Avoid treating vegetables of which the harvest period for consumption is near. The presence of a large amounts of copper in the must has adverse effects on the yeast responsible for the fermentation of wine. Bordeaux mixture is toxic to humans, fish and other animals. Thus, it is recommended to store it in a container kept out of reach of children.

Related posts:

  1. Treating fruit trees
  2. Stimulating plant growth and preventing diseases
  3. Growing an apple tree

Published in Products by Alexander on 06 Jul 2011