84 Farmers’ Bulletin 1270. 
sults have been obtained, but, on the whole, dust mixtures have not given as 
efficient control as liquid sprays, and in certain apple districts have been quite 
ineffective. The dust mixtures now usually employed contain 10 per cent of 
lead arsenate and from 75 to 90 
per cent of finely divided sul- 
phur. A filler, such as hydrated 
lime or gypsum, is often desir- 
able, as its admixture makes a 
better flowing dust and lessens 
the cost of the mixture. It is 
believed that a 75 per cent sul- 
phur content will yield as good 
results as a higher percentage. 
A complete dust mixture, con- 
taining arsenate of lead, sulphur, 
and nicotine, has been tried out 
during the past few years, the 
nicotine having been added in an 
effort to combat apple aphids, 
red bugs, etc. Some success has 
been reported with this mixture, 
but the quantity of nicotine re- 
quired makes the application 
somewhat expensive. An effort is now being made to develop a good copper sul- 
phate and lime dust to replace the sulphur. Some promising results have been 
obtained, but further tests are necessary to determine fully its efficiency against 
fungous diseases. 
Fic. 174.—Construction of tree band made of 
cotton and tarred paper. 
TREE-BANDING MATERIALS.” 
Bands of sticky material 4 to 5 inches wide applied around tree trunks some- 
times may be used to advantage to prevent caterpillars, climbing cutworms, 
and certain other insects from 
climbing trees. These bands are 
also employed to prevent non- 
flying and wingless-moths, such 
as the gipsy moth, cankerworm 
moths, tussock moths, etc., from 
ascending trees to deposit their 
eggs. Cotton batting and wire 
screen also are used in making 
protective bands. 
The indiscriminate use. of 
these bands, as well as mechani- 
cal barriers, is to be discouraged. 
Their use in parks is sometimes 
noted on trees which are not sub- 
ject to attack by insects against 
which they would have value. 
As a rule, it is advisable to ob- 
tain advice as to their use from 
x Fic. 175.—Completed tree band of cotton and 
entomologists, _ tarred paper with band of sticky material. 
STICKY TREE BANDS. 
Sticky bands are sometimes injurious to the tree, but injury may be avoided 
by spreading the adhesive on a strip of heavy paper encircling the tree trunk. 
*’ For more complete information on tree-banding materials see United States Depart- 
ment of Agriculture Farmers’ Bulletin 908, 
