8 
COLORADO EXPERIMENT STATION 
trees so that the lice at the roots can not migrate to the top. For the ap¬ 
plication of these bands see next paragraph. 
tangle:i?oot bands 
In the experiments upon the Western Slope in particular, large num¬ 
bers of Tanglefoot bands have been used. This material is put out by the 
O. & W. Thum Co., Grand Rapids, Michigan and is the sticky material put 
upon the Tanglefoot Fly-Paper. When at all abundant upon the trees, 
the newly born lice are much inclined to travel about and it is often aston¬ 
ish to see the number of lice that will be captured in these bands. On the 
/th of June, 1907, it was estimated that bands that had been on since the 
preceding fall had as many as 100,000 lice each in many cases. The bands 
remain fresh for several months and may be quickly freshened by rubbing 
a paddle over them, when they become filled with insects and dirt. 
Apparently these bands do no harm to trees, but what their effect might 
be when continued for years we are unable to say.* In most instances we 
have put them directly upon the bark but it would be safer, so far as any 
possible injury to the tree is concerned, to put a band of stout paper around 
the trunk and then put the Tanglefoot upon that. To make certain that no 
lice should pass under the band, a light band of the cheapest cotton batting 
under the paper would be advisable. This band, in connection with the 
spring spraying mentioned above, we believe to be the surest method of 
freeing the tree tops of woolly aphis. 
MOUNDING AND CULTIVATING 
The woolly aphis is not a burrowing insect in any true sense of tlie 
word. The lice that come down the trees get into the ground by way of 
the cracks or other openings in the soil that are large enough to allow them 
to enter. The lice that sometimes infest distant roots do not get to them 
by crawling there all the way from the crown of the tree but they get 
down to them directly from the surface above. So far as possible, the des¬ 
cending over-winter lice congregate about the crown of the tree where they 
are able to get below the surface in the large cracks between the trunk and 
the earth. The migration both to and from the roots can be somewhat, 
often very largely, prevented by cultivating the surface of the soil and by 
stirring and compacting and even slightly mounding the earth about the 
crown of the tree and by re-stirring this earth when it becomes compact 
after a rain or an irrigation. 
TRIMMINGS 
When the lice become very abundant upon water sprouts and suckers, 
something can be done to lessen the number by thoroughly cutting out these 
growths. A thorough thinning of the top so that plenty of sunlight can 
enter has been noticed to lessen the number of lice which find the most 
congenial locations for their development in dense shade and upon the 
north side of the limbs, at least in sunny Colorado. 
*Mr. Geo. P. Weldon, reports, from recent observations upon the 
Western Slope in Colorado, rather severe injuries from the application of 
Tanglefoot bands that have been directly upon the bark for a year or more. 
