50 
C0I.0RAD0 Experiment Station 
as a spray. A part of the arsenical spray, especially when used in 
excessive amounts, eventually reaches the base of the tree, and 
brings about injury to the crown of the tree. 
Headden says, ‘'This trouble begins, in by far the greater num¬ 
ber of cases, at the crown of the tree and subsequently involves both 
trunk and roots. The first marked symptom is an early ripening of 
the foliage, usually followed by death about midsummer of the en¬ 
suing year. The crown of the tree is found to be girdled, the bark 
on portions of the trunk dead and sunken, and most of the roots 
dead, their bark destroyed and the woody tissue discolored, usu¬ 
ally a light shade of brown, and sometimes exteriorly blackened.’' 
Arsenical sprays constitute our most valuable insecticides and 
their use is not to be discouraged. But they should not be applied 
in excessive amounts. There is a tendency with some to give more 
applications than necessary. 
“Seepage.” —Trees dying from too much water show symp¬ 
toms markedly different from those affected with “niter.” All the 
leaves of the tree may turn yellow. Discoloration of the leaf does 
not progress from the tip along the margins, as in “niter” leaves, 
but the leaf seems to be affected as a whole. Affected portions of 
“niter” leaves are brownish in color from the first, never yellowish. 
Trees killed by too much water never show girdling at the crown 
as do those killed by arsenic. 
PREPARATION OF SPRAY MIXTURES AND 
DISINFECTANTS. 
Bordeaux Mixture. 
Materials Used — 
Copper sulfate (blue vitriol). 4 lbs. 
Stone lime. 5 lbs. 
Water . 50 gals. 
This makes a 4-5-50 mixture of the spray. The amount of 
copper sulfate can be varied according to the formula given. The 
weight of stone lime should be equal to or exceed the weight of cop¬ 
per sulfate. 
Apparatus — 
2 half barrels with a capacity of about 30 gallons, made by sawing 
in two a 60-gallon barrel. 
1 60-gailon mixing barrel. 
2 or more wooden pails. 
1 strong paddle, about 7 feet long. 
1 pair hand scales. 
1 strainer, of cloth or 20-mesh brass gauze. 
