According to &lt;a href='http://hdoa.hawaii.gov/pi/main/crb/' target='_blank'&gt;Hawaii's Department of Agriculture&lt;/a&gt; site the damage palm trees by boring into the crown of the tree to feed on the sap. They cut through developing leaves, causing damage to the fronds. V-shaped cuts in the fronds and holes through the midrib are visible as leaves mature and unfold.