A significant pest of Pritchardia palms is the banana moth, Opogona
sacchari. The triangle palm is also attacked by this moth. It seems that
the female moth targets wounded or stressed palm tissue to lay her eggs.
Stresses can include drought, flooding, mechanical wounding, poor nutrition,
and herbicide injury. The larvae generally feed on decaying and dead plant
tissue but will feed on living tissue, too, causing extensive damage. In
affected palms, larval tunneling, along with the characteristic frass (insect
droppings), can often be seen. Fully developed caterpillars measure just over
an inch. The adults have greyish brown wings are 3/8 to 5/8 inches long.
The main treatment is prevention: keep palms growing well; give them
adequate fertilizer, and supplemental water during a drought. Gardeners also need
to be careful with the weedwacker! Female moths are looking for wounds to lay
their eggs. Bt (bacillus thuringiensis), an organic insecticide, can be applied
to these wounds, as well as those caused during pruning.
For more information about this pest see the CTAHR Cooperative
Extension Service publication, “Banana Moth – A Potentially Fatal Pest of
Pritchardia and Other Palms”, by Scot Nelson and Mark Wright. For new readers
CTAHR is College of Tropical Agriculture and Human Resources - University of Hawaii - Manoa.
