Plant Sanitation. 



390 



Attention is called to the occasional injury to foliage and'fruit from the use 

 of Bordeaux mixture. This seems due in many instances to the use of too little lime 

 in making the fungicide, but similar results have been observed when there was an 

 excess of lime used. The amount of injury seems to vary for different plants, and 

 it is influenced by different climatic conditions. In general the excess of lime seems 

 to check the injurious effects of copper sulphate, but in the case of apples and 

 peaches it is not wholly able to prevent it, and in addition a superabundance of lime 

 very greatly reduces the adhesiveness of the fungicide. The excess of lime is also 

 associated with a reduction in the amount of copper hydrate, and, as a consequence 

 its fungicidal action is diminished. 



The author inclines to the belief that in practice it will found best to use 

 equal weights of lime and copper sulphate. There appears to be no reason for not 

 following this proportion in spraying grapes, apples, pears and potatoes. For 

 spraying peaches two parts of lime to one part of copper sulphate should be employed, 

 and the number of applications should be as limited as possible, sprayings never 

 being made during rainy or cloudy weather. — Experiment Station Record, U. S. 

 Department of Agriculture, No. 5, Vol. XVII. 



LEAP DISEASE OP THE GROUND-NUT. 



The important ground-nut (Arachis hypogcea) cultivation of the Bombay 

 Presidency has rapidly declined of recent years mainly owing to a fungus disease 

 (Septogloeum arachidis) locally known as tikka, a description of which is given in 

 paragraph 27 of Dr. Butler's report (part IV). This disease is also extending in the 

 Madras Presidency. Spraying has not been successful, but if the surmise is correct 

 that infection is carried in the seed, seed-treatment may be possible. Efforts have 

 mainly been directed towards securing a disease-resistant variety. With this object 

 varieties have been obtained from Japan, America, Africa, Spain and Mauritius. 

 These are all being tested on the Bombay farms both for disease-resisting qualities and 

 for yield in this country. A new farm has been started in South Arcot (Madras) as a 

 ground-nut experiment station where this disease will be fully investigated. The 

 best of the foreign varieties were also distributed for trial in different parts of India. 



The cultivation at Pusa was a failure owing to the attacks of caterpillars. 

 In other parts, the " Virginian" and " Pondicherry " varieties seem to have done the 

 best. The oil-yielding quality has been determined by the Agricultural Chemist to 

 the Government of India who found that the percentage in the kernels varied from 

 40 to 50, the "Mauritius" varieties grown in Madras generally giving the best 

 results. The indigenous varieties contain from 39 to 44 per cent, of oil. "Virginia" 

 gave 44 "33 percent., and "Japanese small" 49-75 per cent. — Annual Report of the 

 Imperial Department of Agriculture of India for 1904-05, 



Fungicides and their Use in Preventing Diseases of Fruits. 



FUNGICIDES AND THEIR PREPARATION. COPPER COMPOUNDS. 



FORMULAS FOR BORDEAUX MIXTURE. 



The most valuable for use in combating plant diseases is Bordeaux mixture, 

 consisting of a mixture of copper sulphate (blue stone) and stone lime slaked in 

 water. The formula varies somewhat according to the use which is to be made 

 of the spray. Following are the ones most used :— 



Standard Bordeaux Mixture.— The following formula, known as the 6—4—50 

 formula, the ingredients being mentioned always in the same order, is used in the 

 preparation of the Standard Bordeaux mixture : 



Copper sulphate (bluestone) ... ... ... pounds 6 



Lime ... ... ... ... .-. do 4 



Water to make ... ... ... ... gallons 50 



