LOGGING PRACTICE IN THE LAKE STATES 41 
promises a fair return of interest on the capital invested. For 
private owners, however, planting is advisable at present only on the 
better soils and with species such as white pine, Norway pine, and 
white spruce. 
PROTECTIVE MEASURES AGAINST DISEASES AND INSECTS 
BLISTER RUST AND ROTS 
In any scheme of intensive forest practice the control of diseases 
and insects must be taken into account. Aside from the white-pine 
blister rust and some diseases of aspen and paper birch, the forests 
of the Lake States are comparatively free of serious disease. The 
white-pine blister rust, although always a menace, is at present under 
control in the region, and serious losses of white pine are not likely 
from this cause if the white-pine forests are protected by the eradi- 
cation of gooseberry and current bushes from the areas of and 
adjoining white-pine stands. 
Decay in aspen and paper birch, characteristic when the stands 
reach an age of about 60 years, is quite prevalent, but on account of 
the abundance of aspen throughout the region and its merchanta- 
bility before the decay becomes serious, this offers no serious obstacle 
to growing aspen as a crop. There is no exact knowledge of the 
manner in which this disease spreads; the method of its control at 
present is merely to cut and utilize the trees as soon as they become 
infested. The same holds true of all other species. 
INSECTS 
The insect depredations, however, are more serious.’ The spruce 
bud worm has caused much damage in the Lake States during the 
past 15 years. ‘The tamarack throughout the region has suffered 
severely from the attacks of the larch sawfly, which has practically 
eliminated all large tamarack. Recently, the jack-pine sawfly and 
the jack-pine tip moth have been abundant, and finally the white pine 
weevil has done considerable damage in young plantations of white 
ine. 
The ordinary mechanical and chemical methods of insect control 
usually applicable in orchards and for shade trees are as a rule too 
expensive to make their use economical in forests. Spraying, for 
instance, in addition to the cost of insecticides, calls for the use of 
expensive machinery and equipment. Other methods which might 
well be used with shade trees, such as banding and tree surgery, are 
too expensive for use in the forest. Only in rare instances can these 
methods be economically applied, even to farm woodlands. In the 
control of forest insects prevention must always be the key, and this | 
presupposes a knowledge of the life history and the methods ot 
attack of the insects. 
WHITE PINE WEEVIL 
As a means of reducing the damage caused by the pine weevil in 
_a white-pine plantation, the plantation should be set out very dense, 
7™The information regarding forest insects_and their control was furnished by S. A. 
Graham, forest entomologist, attached to the Lake States Forest Experiment Station, 
