THREE-LINED FIG-TREE BORER 
By J. R. Horton, 
Scientific Assistant , Tropical and Subtropical Fruit Insect Investigations , Bureau of 
Entomology , United States Department of Agriculture 
INTRODUCTION 
The adult three-lined fig-tree borer (Ptychodes trilineatus L-) is a 
large, longitudinally striped, long-homed, wood-boring beetle of the 
family Cerambycidae, which does considerable damage to fig trees 
{Ficus carica) in the Southern States by boring into the larger branches 
and trunks. 1 
This insect occurs throughout the southern United States from Florida 
to Houston, Texas, and from South Carolina to the Gulf. It has also 
been reported from parts of Mexico, British Honduras, Nicaragua, 
Costa Rica, Guatemala, Panama, and the West Indies, Colombia, and 
Venezuela, South America, and Tahiti, Oceania. The adult beetle 
causes some injury by feeding upon the fruit, leaves, and bark of fig 
trees and by ovipositing in the bark, but the greatest amount of damage 
is done by this insect while in the larval state. The larva is a white, 
flat-headed borer, or sawyer, which mines its way into the larger branches 
and trunks of the trees (PI. 37), where it feeds upon the wood for 
from three months to more than one year, and reaches a length of nearly 
2 inches, before changing to the pupa. 
INJURIOUSNESS 
The borers live in dry as well as in green wood, and specimens have 
lived for two or three weeks in other woods than the fig. Two larvae 
from one lot under observation ate their way out of their blocks of fig 
wood and into the top of a cypress table, where they tunneled for 2 
and 3 inches, respectively, and completed the transformation to the 
adult stage. They appear to prefer wood which is partly dead and has 
lost some of its sap to healthy green wood, and therefore attack prin¬ 
cipally those trees or branches which are injured or diseased. Any 
injury, however, such as the breaking of a large limb, may invite the 
deposition of many eggs by the adult beetle, and the branch will then 
be killed by the borers. The first attack will, furthermore, generally 
be followed by others until the whole tree becomes involved and is 
finally killed by the insect. 
Favorite points of attack are near wounds made by the breaking of 
large limbs, untreated saw cuts, splitting of the trunk, the knots formed 
1 Several other borers also attack fig trees in the Southern States—for example, Leptostylus biustus Lee., 
Goes sp„ Stephanoderes sp. f and Ataxia crypta Say—and are found working in the same trees with 
Ptychodes trilineatus. 
( 371 ) 
Journal of Agricultural Research, 
Washington, D. C. 
kp 
Vol. XI, No. 8 
Nov. 19, 1917 
Key No. K—58 
