1386 Ture VecreTasBLte Inpustry In New York Strate 
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 off quickly, and if applied before the bugs are well 
hatched out, the application must be repeated, materiall 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 31% or 4 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. 
