1386 The Vegetable Industry in New York State 



periment Station, once told me, that 50 per cent, of the potato 

 leaves sent to him for examination for blight had simply paris 

 green injury. Next, being in the form of an amorphous powder, it 

 washes on' quickly, and if applied before the bugs are well 

 hatched out, the application must be repeated, material] in- 

 creasing the cost. With these facts before us, I recommend 

 arsenate of lead. This will not injure the foliage in any 

 quantity. It is in a paste form and will adhere a long time. 

 Hence, it can be put on with impunity when the bugs first 

 appear, and it will remain for those hatching later. It is not 

 so quick in its action as the green, and many who have tried it 

 have complained that it did not kill the bugs. This was my 

 own experience the first time I used it, waiting until the bugs 

 were abundant and applying it with a sprayer which did not 

 thoroughly cover the vines. Since I have learned to use it at 

 the first appearance of the bugs, and apply it in such a way that 

 every leaf is covered, I have frequently found one application 

 sufficient for the season. 



Arsenate of lead is sold on a guaranteed analysis of the arsenic 

 oxide it contains. Therefore, one can readily determine its com- 

 mercial value, and also how much to use. If, for instance, 1 pound 

 of paris green — which should be 50 per cent, arsenic — to 50 

 gallons of water has been found sufficient to kill the bugs, one 

 should use 3^2 or I pounds of the lead to a like amount of water, 

 or bordeaux. 



DISEASES 



A disease which does much injury is " tip burn," often mis- 

 taken for blight, but entirely different. The life history of this 

 has not been thoroughly worked out. One theory, and to my mind 

 a very plausible one, is that when the early part of the season is 

 wet and the plants heavily fed with nitrogenous fertilizers, a rank, 

 rather soft growth follows.' Later in the season it turns dry. 

 There is more plant than can well be supported, and the extrem- 

 ities of the leaf, farthest from the source of supply, and being only 

 imperfectly nourished, is easily affected by the disease germ 

 which the more vigorous parts of the plant resist. Bordeaux is 

 a good remedy, but it must be evident, if the above is correct, that 

 an abundant water supply and plant food are conditions which 

 make this disease less likely to occur. 



