134 THE PLUM IN KANSAS. 



FRUIT-TREE BARK-BEETLE. 

 Press Bulletin No. 14, Kansas Experiment Station. 



Of the insects that have been introduced into Kansas during the 

 past few years, none seem to be more destructive to stone-fruit trees 

 than the fruit-tree bark-beetle, or shot-hole borer, as it is sometimes 

 called, from its peculiar habit of riddling the bark of the trees with 

 numerous small holes. It has been found in Riley, Bourbon and 

 Allen counties, and without doubt is present in a large number of the 

 other counties of the state. In Allen county it was very numerous, 

 particularly in an orchard of cherry trees which were suffering badly 

 from the cherry scale. 



The presence of the pest will probably be first shown by the wilt- 

 ing and falling of the leaves at an unseasonable time. A close ex- 

 amination of the tree infested with the insect will reveal numerous 

 small holes in the bark, from which, in the case of the stone-fruit 

 trees, such as the plum, peach, cherry, etc., there is a considerable 

 exudation of gum. To show how the insect may riddle a tree, a i^iece 

 of bark less than an inch square, taken from an infested cherry tree, 

 contained nineteen perforations about the size of a pin -head. 



The insect that is the cause of the mischief is a small beetle about 

 one-tenth of an inch in length by about one-third as wide. It is 

 black in color, with the exception of the wing- covers and the lower 

 part of the legs, which are reddish. 



With the beginning of spring the beetles appear, and commence to 

 bore small, round holes through the bark to the sap-wood, where they 

 make a central burrow or brood chamber, on each side of which little 

 pockets are made, in which eggs are deposited. As the larvse hatch 

 from the eggs they commence to make burrows away from and at 

 right angles to the brood chamber, which become larger as the larvae 

 develop in size. 



The larva is a small grub about one-tenth of an inch in length. It 

 is footless and white, with the exception of the head, which is brownish. 



When the larva has attained its full growth it makes a slightly 

 enlarged chamber, in which it pujDates. Upon becoming an adult, 

 the beetle makes its way out through small holes in the bark and 

 escapes. It takes about a month for the insect to go through its va- 

 rious stages, so that during the summer there may be several broods. 

 Many of the beetles, upon emerging, will turn and renew their attack 

 upon the tree, thus increasing the damage that has already been done. 

 In time, the tree becomes completely girdled by tlie numerous chan- 

 nels, and dies. 



Strong and vigorous fruit-trees may resist for a time the attacks of 

 the beetles through the exudation of the gum, which seems to be ob- 

 noxious to both the beetles and the larvae. But if the attacks are con- 



