106 NEBRASKA STATE HORTICULTURAL SOCIETY 



larger in size. The usual treatment for boring insects, fumigation by 

 carbon bisulphide, is not recommended against the peach borer because 

 of, the generally more or less closed condition of the burrows of the 

 larvae and the fact that its use apparently injures the health of the tree. 

 It is said that applications of boiling water about the base of the tree 

 will destroy the larva, but the expediency of this method is questionable. 

 Tn dealing with this insect it is well to keep up the various means of con- 

 trol here mentioned from year to year upon all the stone fruit trees 

 in the orchard, and thus prevent the insect from becoming very common. 

 The Fmit-tree Bark-beetle — (Scolytns rtigulous Ratz). 



Another one of our common Nebraska horticultural pests is known 

 to entomologists under the above name but is also frequently termed the 

 'shot-borer" because its presence is made apparent by the appearauc? of 

 many small round holes in the outer bark of the tree resembling shot 

 holes. These holes are formed by the parent beetles in entering the 

 bark to deposit their eggs and by the newly formed beetles which have 

 developed under the bark in emerging for the purpose of dissemination 

 among the trees of the orchard. They may be found, not only in plum, 

 cherry and peach, but also in the apple and pear and other trees. In 

 attacking stone fruit trees there is likely to be an exudation of gum at 

 these holes. 



The insect causing this injury is a small beetle about one-tenth of 

 an inch long, in color black, with the tips of the wing-covers and part 

 of the legs dull red. It belongs to the family of bark beetles (Scolytidae) 

 and it a native of Europe. It was first observed in this country injuring 

 peach trees in 1877 and within a few years established itself over all of the 

 eastern states east of the Rocky mountains from New England, New 

 York and Michigan, south to Georgia, Alabama and Arkansas. 



This insect is particularly likely to attack trees after they have been 

 injured by the peach-tree borer or through some other cause, and it 

 may be said that as a rule the attack by these bark-beetles is confined to 

 diseased and injured trees. But sometimes perfectly sound trees are 

 severely attacked and sometimes seriously injured by the fruit-tree 

 bark-beetle. Peach trees in full \itality are likely to repel the beetles by 

 the abundant gummy exudations, so that they soon desert their burrows 

 and seek other trees, but when the vitality of the tree is lowered so that 

 these copious exudations cease a heavy attack and early death of the 

 tree is likely to follow. The beetles early in the spring burrow into the 

 small terminal twigs, causing their death and the wilting of the leaves 

 they bear. 



The first beetles make their appearance quite early in the spring, 

 when they crawl about over the orchard trees and penetrate through the 

 bark into the sapwood. The female beetle then forms in the bark and 

 adjacent wood a large vertical brood gallery from one-half to two inches 

 in length, and along the sides of this she constructs many little side 

 pockets in which she lays her eggs. The construction of this gallery 

 is completed in less than a week. Within three days these eggs hatch 



