10 BULLETIN 787, U. S. DEPARTMENT OE AGRICULTURE. 
small, naturally pruned dead branches are seen and many trees are 
thinned out naturally as the others increase in size. Few root sprouts 
appear. Infested plantations are very irregular in outline; broken, 
tops, trees of irregular size, and many root sprouts and suckers are 
characteristic indications of borer damage. 
CONDITIONS UNDER WHICH LOCUST CAN BE GROWN. 
From the history of the foregoing tracts it is evident that black 
locust can be grown profitably under circumstances that require little 
care, or, in fact, better results are obtained without too much atten- 
tion. After comparing all the data available it seems that provision 
for sufficient shade during the period of growth subject to borer 
attach is all that is necessary in order that this tree may be grown 
successfully. 
This can be achieved by some system of close and mixed plant- 
ing. Experiments of such a character should be tried. In nature it 
is accomplished by close reproduction coming up around the seed 
tree, by root sprouts from older trees, or often by the mixture of 
other plants growing with the locusts. Weeds and vines often form 
the needed shade, as illustrated by trees in old fence rows. It is very 
essential that this shade be present after the trees reach 1| to 2 
inches in diameter, and that it be continued until they attain 5 or 6 
inches. After this time thinning and pruning can be done with 
little or no subsequent injury by the borers. 
Close planting or thick growth of these trees also is necessary to 
produce straight, unbranched boles. Trees in the open are always 
much branched and rather crooked, but those grown in forests are 
tall, straight, and naturally pruned while the branches are quite 
small. 
That difference in site or locality is not the influencing factor in 
the growing of uninjured trees is evident from the fact that in ^ 
locality examined it was possible to find examples of borer-free and 
destroyed trees growing 100 yards apart. It is also evident that 
goldenrod is not necessarily associated with greater damage by the 
borer, for in the same abandoned field, massed with this plant, were 
found plots of trees absolutely free from injury and near-by isolated 
trees badly infested. Again, localities where no goldenrod is growing 
may have borer-infested trees, the adults feeding on other composites, 
as illustrated by example 7. 
The idea has been advanced that the borers are more abundant 
in some localities than in others and that this will account for the 
difference in infestation. This difference can not be sustained, as the 
beetles are present everywhere within the natural range of this tree. 
Side by side we find stands of badly infested trees and' trees contain- 
ing no borers. It is rather to be believed that in localities where locust 
