The Buffer Strip

No matter which means of control is used, success hinges upon treating all stage 1 trees. The best insurance is to cut a buffer strip of uninfested pines around the active head of a spreading spot. This tactic interrupts the beetles' flow of attractants and stops their advance. The buffer strip also provides a margin of error, just in case attacked pines were initially overlooked or the spot has expanded since then.

A buffer strip 10-40 feet wide is enough for medium and low priority spots and for high priority spots with fewer than 30 trees. But a buffer strip 40-100 feet wide is needed for large high priority spots (fig. 18). As a rule of thumb, the number of trees in the buffer strip should not be more than the combined number of stage 1 and stage 2 pines in the spot being treated.