10 July. 1918.] Notes on Vine Black Spot. 425 



healthy wood for future seasons. Withholding of water, in the greatest 

 measure possible, will greatly promote this object. 



The condition of the grooving portion of the vine, as regards succu- 

 lence, has also considerable bearing on receptivity for infection ; moderate 

 growth, which is rather dry and hard in its nature, fears infection less; 

 than rank, sappy growth. Anything tending to insure the former 

 condition will lessen danger; in this connexion, too little, rather than too 

 much, water is strongly recommended. Likewise with manuring — phos- 

 j^hatic and potassic manures give tone to the plant, and tend to increase 

 resistance to disease. Dressings with lime and gypsum will, by liberat- 

 ing combined potash, exercise a similar action. Nitrogen, on the other 

 hand, especially if in excess, tends to promote rank growth ; it should be 

 cautiously used, though it must be remembered that vines which suffered 

 severe damage last year are depressed in their vegetation, and require 

 building up. 



Attention to these cultural points is certainly desirable; nevertheless, 

 too much must not be expected of them. They are only supplementary 

 to, but in no sense a substitute for, the standard treatment (swabbing 

 and spraying), which alone can afford reliable protection. 



Blackbekry vines are most difficult to eradicate, especially as merely 

 cutting down occasionally tends to strengthen the root growth, and 

 ultimately to increase the trouble. 



Where the pest is confined to a small area, intended for constant culti- 

 vation, trenching to a depth of 18 inches to 2 feet, and removing all 

 growth to that depth, is the surest way, though laborious. Every part 

 — roots, butts, and vines — should be burnt. 



The treatment recommended by the Department is the caustic soda 

 method. This chemical, of a strength of 1 lb. caustic soda to 2 gallons of 

 waier, has the advantage of being much less dangerous to animal life 

 than arsenical solutions. It is best applied as follows: — 



On small areas, first cut the vines down close to the ground, and 

 remove them from the area for burning later. Then, from a watering- 

 can, with the rose attached, give the surface from which the vines have 

 been cut a thorough soaking of the above solution. The area is then left 

 until a new growth springs up, and has grown to 4 or 5 inches high. It 

 is not necessary to cut this growth doMoi, but it is advisable to give it a 

 further soaking of the solution, which will soon kill more of the tops and 

 root, but, perhaps, still will not kill the lot. This process will need to 

 be repeated, so as to keep the leaf growth in check, for it is only by 

 keeping the tops down that the roots can be ultimately killed. 



On larger areas it will be best to use a mounted spray pump outfit, 

 using an Edgell release valve to regulate the flow of spray. 



.\ soluiion of arsenite of soda acts in a similar way, but owing to its 

 highly poisonous nature, and the danger from children picking the fruit, 

 it is not recommended. 



A flock of sheep or goats kept on an infected area for a few months 

 helps greatly in eradicating this pest. It is best to tether the goats, and 

 to move them about as soon as they have nibbled off all the green shoots. 

 — Agricultural Gazette of New South Wales, June, 1918. 



