38 BULLETIN 149 7, U. S. DEPARTMENT OF AGRICULTURE 
The plantations of white spruce were still small and had not been 
attacked by insects. The spruce buclworm which has been so destruc- 
tive in the natural stands of balsam fir and spruce in northern Min- 
nesota is much less likely to attack stands of white spruce on upland 
sites where balsam fir is not associated with the spruce, since the in- 
sect prefers the balsam fir. The danger is still further reduced when 
the white spruce is planted in mixture with northern white or Nor- 
way pine. 
The larch sawfly has almost completely destroyed the larger timber 
of native tamarack in the region. The tamarack is more likely to be 
able to survive this damage when it is planted on upland sites. This 
insect also attacks the European larch. 
Grasshoppers may prove very destructive to young plantations 
just established and are liable to be more serious in dry years. In 
one year fall planting on the Michigan State forests had to be ter- 
minated because the grasshoppers ate the seedlings as fast as they 
were planted. 
The larvae of the June beetle, commonly known as white grubs, 
undoubtedly cause some mortality in many of the plantations by 
cutting off the roots before the trees are well established. In the 
eastern part of the northern peninsula, of Michigan, heavy losses in 
plantations have been ascribed to this cause. On the Minnesota 
National Forest, also, the white grubs do considerable damage. 
Elsewhere, however, the damage has not been excessive. 
Ants have been known to kill patches of pine in plantations, and 
occasional trees were noticed, usually northern white pine, which may 
have been killed by them. They are not, however, a serious cause 
of damage. 
If insect damage is found in forest plantations, specimens of the 
insect and its work should be collected and sent to the representative 
of the Bureau of Entomology, United States Department of Agri- 
culture, who should be addressed as Forest Entomologist, School of 
Forestry and Conservation, University of Michigan, Ann Arbor, 
Mich. He is prepared to identify the insect and recommend 
measures for its control. 
FUNGUS DISEASES 
Fungi are a minor cause of damage in the plantations in the Lake 
States to-day. The most dangerous one is undoubtedly the white- 
pine blister rust, which attacks and kills white pines. No damage 
from this fungus was observed, however, in the plantations examined. 
Trees may be protected from it by eradicating all current and goose- 
berry bushes within 900 feet of the plantation. White pine should 
not be planted within a mile of black currants (R. nigncm.Ij.) Where 
currants or gooseberries are so abundant as to make the cost of their 
eradication prohibitive, species other than northern white pine 
should be planted. 
Jack pine is subject to a stem rust (Cronartiwn cerebrum (Peck) 
Hedge, and Long) which causes bulb-like swellings on the branches. 
Only occasional branches and trees are infected, however, and the 
damage is not serious. Eight per cent of the jack pine plantations 
had 1 or 2 per cent of the trees infested. 
