What Happened to this Frond?

Some of the fronds of cabbage palm (Sabal palmetto) at Oslo Riverfront Conservation Area (ORCA) show signs of the handiwork of the native palm leaf skeletonizer (Homaledra sabalella).  This pest plagues native palms including cabbage palms and saw palmettos (Serenoa reopens , as well as palmate non-native palms like coconut palms (Cocos nucifera), Chinese fan palm (Livistona chinensis), Mexican fan palm (Washingtonia robusta), and red latan palm [Latania lontaroides].

The culprit is a small grey-brown moth which lays its eggs on older fronds.  After the eggs hatch, the larvae feed on the tissue between the leaf veins, disrupting the vascular tissue and turning the desiccated parts of the the leaf an unsightly “skeletonized” brown.  The larvae can grow to be .5″ long and are creamy white with 8 faint reddish length-wise stripes.  They should be dispatched whenever possible.

The larvae are gregarious (feed together) and produce brown frass-laced silk tubes in which to take they shelter.    You can (and should) use water pressure to remove them.  More than 5 generations are possible each year.

Healthy palms are not killed by attacks by this native moth.  Its handiwork is distinctive..