262 



THE AGBICVLTVBAL JOURNAL. 



done to mitigate the effects of many of 

 them, and with the object of placing a 

 few reminders before readers of the 

 Journal these notes are penned. 



Gkapb Troubles. 



GRAPES AFFECTED WITH BLACK SPOT. 



If Natal does not boast anything very 

 extensive in the matter of grape cultiva- 

 tion, still there are many individuals — 

 particularly dwellers in towns and 

 villages — who have one or several vines. 

 Most of these vines are, of course, the 

 harsh-tasting, but vigorous, Catawba ; 

 other finer varieties, however, exist, and 

 these, when free from fungus troubles, 

 produce excellent frnit. The majority, 

 unfortunately, are very subject to both 

 " black spot " and " mildew," both of 

 which diseases entirely mm the berries, 

 and, to a great extent, the foliage also. 

 Both are essentially summer pests, re- 

 quiring, in common with other fungi, 

 heat and moisture for their development. 

 During the winter the spores or seeds 

 lie dormant upon the vine, or on the walls 

 and trellis supports, and in the soil, ready 

 to germinate and infest the green growth 

 in the spring and summer. Now a great 

 deal may be done whilst the vine is 

 dormant to mitigate the attack of the 

 l)lack spot disease, and the same measures 

 cannot fail to act beneficially in the case 

 of mildew diseases as well. 



The treatment consists in gathering 

 and burning as much fallen foilage as 

 possible, and destroying by fire all the 

 l)runiiigs. After the vine is pruned it 

 should have as much of the old loose 

 bark rubbed off as possible, and then 

 dressed — together with any supports or 

 adjoining walls- with some fungicide 



which will destroy the germs. For this 

 purpose strong Bordeaux mixture may be 

 used, or the following solution : — 



Hot water 100 parts 



Iron sulphate, as much as the water 



will dissolve 

 Sulphuric acid ... One part. 

 This is regularly used in European vine- 

 yards, and is highly valued as a winter 

 application. Considerable care has to be 

 taken in applying the solution, as it will 

 destroy machinery and clothing, and, in 

 fact, everything it comes in contact with. 

 It is usually swabbed on with the aid 

 of rags tied on to a stick, and, of course, 

 can only be applied whilst the vines are 

 quite dormant. If this treatment is 

 followed up by sprayings with Bordeaux 

 mixture ; one before the time of blossom- 

 ing, and one or two after the setting of 

 the berries, stopping when the grapes 

 begin to ripen, the disease can be 

 effectively checked. 



Instructions for the preparation of Bor- 

 deaux mixture have already appeared 

 several times in these pages, but they 

 may safely be repeated here : — 



Copper sulphate (best)... G pounds 



Quicklime 6 „ 



Water 40 to 50 gallons 



Dissolve the copper sulphate in 4 gallons 

 of water, using a wooden vessel. Slake 

 the lime in another vessel, using an equal 

 amount of water. Then mix the two 

 together— this is best done by pouring 

 the two solutions at the same time into a 

 third vessel. The mixture may then be 

 diluted, and is ready for immediate use. 

 In its preparation air-slaked lime should 

 be avoided. 



Pruning the Grape Vine. 

 Apropos of pruning the grape, it may 

 be pointed out here that this can be done 

 when the season's growth has lost its 

 o-reen appearance and assumed a brown 

 or greyish colour. To test this a shoot 

 shoald" be cut, and if it does not "bleed," 

 that is, if there is no flow of sap, it is safe 

 to prune. The exact time will, of course, 

 vary with the variety and with the season 

 — this winter I have found the last week 

 in May not too early for the varieties 

 coming under my observation in Maritz- 

 burg. Unfortunately the grape has not 

 had sufficient local study for one to speak 

 definitely upon tlie effect of early or late 



