Monday, December 17, 2012

Monkey Pod Round-Headed Borer

What causes sap to ooze from of the limbs of monkey pod trees?                             The probable cause is a beetle called the monkey pod round-headed borer (xystrocera globosa).  Not much is written about this insect, except that it infests the sapwood of stressed trees. The sapwood is the youngest, outer part of the woody stem or trunk of a tree. In many cases, these large trees are not irrigated, consequently, under drought conditions they can become stressed allowing the borer to enter. Generally, in healthy trees, flowing sap will actually deter insects from boring as they might 'drown'; when trees are stressed, the flow of sap may be minimal, allowing the insect to bore, or enter.

 When trees are attacked, the individual infested limbs could die, but typically the tree itself will survive.  If the infected limb is showing obvious signs of decline, removal of that particular branch is the best remedy. Biological control agents, i.e., parasites (the good guys) have been identified attacking this pest. Perhaps they are the reason the round-headed borer is not a major problem.