CONTROL OF ARGENTINE ANT IN CALIFORNIA. 11 
The size of the orchard prevented each band receiving the same 
careful attention given in Experiment 2. Instances were noted 
during the autumn where the bands on slightly attended trees were 
bridged within an hour following the application. 
CONCLUSIONS. 
The conclusion to be reached from these two experiments is that 
the constant attention required to make sticky tree-banding material 
an effective barrier to ants on heavily infested citrus trees renders 
the method impracticable in orchard work. It might be used to 
advantage on a few trees which can be given the necessary attention, 
as, for instance, on house lots or about buildings. 
The general belief that sticky tree-banding material is injurious 
to citrus trees when applied directly to the bark has been found 
erroneous. The writers have never seen a citrus tree killed as a 
result of this treatment. In 1915, 40 three-year-old nursery trees 
were banded. Examination of the bark beneath the bands one year 
after application showed the bark perfectly green and healthy. The 
sticky material on 100 trees banded in September, 1915, was scraped 
off in July, 1916. In no instance was there certainty of injury to 
the bark or cambium. Examination of hundreds of trees which 
have been banded with sticky material for periods ranging from 1 to 
5 years have failed to show definitely a single instance of severe 
injury attributable to the bands. A disease known as gummosis is 
prevalent throughout southern California especially on heavy soils. 
Exudation of gum from this disease, beneath the bands or closely 
adjacent, and the accompanying diseased tissues revealed by remov- 
ing the band, have been sometimes attributed to the banding with 
sticky material, although no cases have been observed where this was 
definitely the cause. Applications to trees soon soften the bark 
beneath somewhat. After about one year the exposed surface of 
the sticky material becomes glazed and by the second year a hard 
exterior coating is found and only the substance adjacent to the tree 
remains moist and sticky. In due time, depending on the thickness 
of the sticky layer, the entire band becomes hard, and subsequently 
is broken by the expanding growth of the trunk. The bark where 
exposed to the air dries and assumes its normal consistency and 
appearance. Heavy bands may require several years to dry. 
Possible injury from sticky tree-banding material might arise from 
removal of heavy bands within a year following their application or 
before they are somewhat dried out. In one case trees heavily 
banded in September were scraped the following July. The bark 
was so injured by the workmen in removing the sticky material that 
a very weak solution of corrosive sublimate was used to disinfect 
