|AGRICULTURE TRIBUNE||Monday, May 14, 2001, Chandigarh, India|
Bordeaux mixture: panacea for disease control in fruit plants
Discovery of Bordeaux Mixture
How to deter schoolboys from pilfering their grapes had been a problem of French farmers in the Modoc region for a long time. A poisonous looking mixture of lime and copper sulphate that struck tenaciously to the leaves when sprinkled on vines near road sides was the answer.
that produces insecticide-free vegetables
mixture: panacea for disease
Discovery of Bordeaux
Preparation of Bordeaux mixture
For preparing the 2:2:250 Bordeaux mixture, dissolve 2 kg of copper sulphate in 125 litres of water. Copper sulphate dissolves slowly in cold water. Hence, in winter it is better to use hot water or suspend copper sulphate in a muslin cloth bag into a non-metallic vessel (wooden barrel or earthen pitcher) so that the material gets dissolved in water and solid impurities, if any, are left out.
Slake 2 kg quick lime in another vessel (earthen or metallic). Avoid plastic container for this purpose. Add some water to the lime to make a paste to which water should be poured slowly to make the volume to 125 litres. Stir vigorously to make a lime suspension.
Mix the copper sulphate solution and lime suspension by pouring them together in the third vessel constantly stirring the mixture with a wooden stick while pouring. The lime solution should be poured through a strainer to keep back all lumps. A light blue liquid is obtained which should be strained through a muslin cloth or sack before putting in spray tank.
Uses of Bordeaux mixture
Test Bordeaux mixture before use
Litmus test: The Bordeaux mixture is alkaline in reaction as it contains more proportion of lime. It should, therefore, turn red litmus paper blue. An excess of copper compound in the mixture may be dangerous to foliage of many plants and is indicated by solution turning blue litmus paper red.
Copper deposition test: It is a simple and practical way of estimating whether or not the mixture contains excess of copper in it. Immerse a bright iron surface such as knife blade or a nail in the upper layer of the liquid for a few minutes. A brick red or bright pink coppery deposit on the metal surface indicates the presence of excess copper and as such the solution is unsafe for use. Therefore, more lime solution should be added to the mixture and the test repeated till no such deposit appears on the clean metallic surface.
Reagent test: A more precise chemical test may be performed using the reagent, potassium ferrocyanide. The reagent may be obtained from a scientific chemical store. A few drops of the Bordeaux mixture are added to little of this reagent in a saucer. If no change occurs, the mixture is safe for use but its turning reddish brown, indicates the presence of excess free copper in it, which is not desired.
Some do’s and don’ts
Other formulations of Bordeaux
Application of the Bordeaux paste can effectively check the attack of collar rots and root rots of fruit trees.
Preparation of Bordeaux paste
Dissolve 2 kg of copper sulphate in 15 litres of water. Slowly slake 3 kg of quick lime in a small amount of water. When slaked, add enough water to make the volume up to 15 litres. Thoroughly mix these concentrated solutions of copper sulphate and lime. This ready-to-use paste of sky blue colour is suitable for application to the cut ends with a brush.
Preparation of Bordeaux paint
Monohydrated copper sulphate can be easily made by heating the copper sulphate crystals on an iron sheet or in a frying pan till they crumble into a white amorphous form which is ground into a fine powder. Monohydrated copper sulphate powder can then be mixed thoroughly with lime dust and homogenised with 3 litres of boiled but cooled linseed oil to make a thick paste. This paste may be stored in a glass jar or other suitable non-metallic vessel for future use. It can be applied to the plant parts with the help of a brush.
that produces insecticide-free vegetables
THE Department of Vegetable Crops, Punjab Agricultural University, has developed net-house technology for the cultivation of vegetables. These vegetables will be insecticide-free under this new technology which is an alternative to the green-house technology. The net-house technology is used in foreign countries and is quite costly compared to the green house technology. However, the results of the new technology are very encouraging and there can be an increase in the [production of vegetables by about 50 per cent and 100 per cent more than open cultivation.
According to Dr J.S. Hundal, Head of the Department of Vegetable Crops, the net-house cultivation was initiated under the guidance of Dr G.S. Kalkat, former Vice-Chancellor, in 2000. This is a very simple technology and a screen-like mosquito net is used to cover the field under which vegetables are grown.
Dr Hundal points out that under the present conditions, farmers are spraying a number of insecticides to save their crops from insect-pest and diseases. There is no law to check it and whatever vegetables come in the market are full of chemical residues which ultimately go into the human system and result in different diseases. The vegetables produced in the open are not fit for export. Therefore, the solution is net-house cultivation without the use of insecticides. Some net-house insects like mite and aphid can be controlled by non-insecticide like lime, sulphur or neam oils.
The Department of Vegetables has built up three net-houses to produce insecticide-free vegetables. A number of vegetables like tomato, brinjal, okra, capsicum, chilli and early cauliflower have been selected for net-house cultivation. The crops like brinjal, okra and tomato are highly prone to fruit borer and farmers have to spray a number of insecticides even double than recommended practices to control borer. The systemic insecticides like Rogour, Metasystoc and Pythroids are highly dangerous to human health. It is hoped to get borer-free brinjal, tomato and okra under net-house.
Dr Hundal says that
the experiments have shown that the yield of vegetables is about 50 to
100 per cent more than open cultivation. Also vegetables take less
time for ripening and the duration of fruiting period is likely to be
extended. Net-house vegetables are likely to get a premium of 50 per
cent in the market as compared to the open cultivation. The consumers
will be ready to pay more for insecticide-free vegetables. The
net-house system saves the plants from different storm, direct rain
and wind which have great effect on plant growth in the open
cultivation. Good results have been achieved in high-value crops like
Shimla mirch which was planted in November and the first picking was
done in February when the price of fruit was quite high.
Farm operations for MAY
— Control weeds in the plant as well as ratoon crop by giving hoeings with bullock-drawn plough or tractor-drawn implement. Due to the prevailing hot weather conditions, the sugarcane crop requires frequent irrigations at eight to 10 days’ interval. Apply 65 kg of urea per acre to the ratoon crop. Moisture conservation may be done by spreading mulch in between the cane rows. Use rice straw/wheat straw/rice husk for mulch. This also checks the growth of weeds.
— For checking attack of black bug, spray 350 ml of Thiodan 35 EC or Dursban 20 EC in 200 litres of water. Direct spray material into the leaf whorl.
— Sugarcane mite can be checked by spraying 400 ml of Malathion 50 EC in 100 litres of water per acre. Destroy baru weed growing nearby which is an alternative host for mite.
— The thrips also damage the sugarcane, particularly the ratoon crop, so spray the crop with 400 ml of Malathion 50 EC or 350 ml of Thiodan 35 EC per acre in 100 litres of water.
— Sometimes iron deficiency appeared in the ratoon and plant crops in the light-textured soils and calcareous soils. Deficiency symptoms first appear in young leaves as yellow stripes between green veins. Later the veins also turn yellow. To control this, spray the crop with 1 kg of ferrous sulphate dissolved in 100 litres of water on the foliage.
— After the harvest of wheat, the bunch variety SG-84/M-522 can be sown up to the first week of May after applying rauni irrigation. Whereas other varieties like M-355, M-522 of M-13 should be sown from May 25 onward with a pre-sowing with 5 g Thiram or 3 g of Indofil M-45 per kg of kernels.
— Apply 25 kg of CAN or 12 kg of urea and 50 kg of single superphosphate at the time of sowing. If the recommended dose of phosphorous has been applied to wheat, its application to groundnut can be omitted. However, under such situation application of 50 kg of gypsum would be required.
—Summer moong is severely attacked by thrips, which are small, dark brown, round in flowers and cause flower drop, deformation of pods, deterioration of grain quality and ultimately heavy reduction in yield. Spray the crop bud initiation stage with 100 ml Rogor 30 EC (dimethoate) or malathion 50 EC or 120 ml metasystox 25 EC (xydemeton methyl) in 100 litres of water per acre.
— Last irrigation to summer moong should be stopped 50-55 days after sowing. This would help in uniform ripening of the crop.
Due to prevailing hot weather conditions, sunflower would require irrigation at 8-10 days interval during this period. Various types of caterpillars such as Cabbage semilooper, Tobacco caterpillar and hairy caterpillars feed on green leaves and defoliate the attacked plants. These larvae can be checked by spraying 500 ml of Thiodan 35 EC or 200 ml Nuvan/Divap/Vapona 100 EC in 100 litres of water per acre. Repeat after two weeks, if necessary. This treatment will also control jassids and other sucking pests in case they appear.
— Progressive Farming, PAU