Evil Weevils

Have you noticed droopy dried fronds dangling on our palm trees? They are under attack by deadly threats. One strikes from the top down, one from the bottom up.

Starting at the top: the South American palm weevil (Rhynchophprus palm arum), a flying 1 1/2 inches long black beetle able to travel up to 15 miles a day that immigrated to San Diego more than 10 years ago has also moved to cities north. This invader’s favorite is the Canary Island palm—but all palms are at risk.The weevil works by drilling into the palm’s leaf base where it then lays its eggs, as many as 690. When hatched, the larvae army eats up the palm’s heart, rotting the core and causing the crown to collapse.

From the ground up: the Fusarium fungus, found in California soil, is fond of overwatered palms. The fungus assaults the palm through its roots. It then proceeds up the trunk clogging the vessels that transport nutrients within the tree. The lower fronds die first, followed by the middle and top growth.

What to do: The city is aware of the danger to city palms. Infected trees with wilted fronds are being taken down, healthy palms are being watched. Residents, however, are responsible for their trees. Keep vigilant. Notify your arborist of abnormalities on your palms. Be sure the tool that prunes your palms is a cleaned flat edge blade so disease does not spread through an unsterilized equipment. Remove palm tree waste rather than reusing it for mulch.