Good News for Brown Lygodium Moth,
Bad News for Old World Climbing Fern

Lisa Jameson, Biologist, Invasive Exotic Plant Control

Here at the Refuge, the good news is the Brown Lygodium moth, Neomusotima conspurcatalis, appears to have become established in some areas despite fears that attempts to transplant the biocontrol species into the Refuge were unsuccessful. From October of 2008 to March of 2009 over 13,000 larva of the Brown Lygodium moth or "Neo" were released in the interior of the Refuge in an effort to control Old World Climbing Fern, Lygodium microphyllum.

Old World Climbing Fern with Moth

Old World Climbing Fern with Bio-control
agent, Brown Lygodium moth.

Old World Climbing Fern, an invasive non-native fern that has infested several thousand acres at the Refuge, is causing the most concern at the Refuge because there are no known methods for effectively mapping or treating this invasive fern. Current treatment strategies are to contain and control the spread of the current acreage with chemical treatments, and to continue monitoring and mapping the infestation until an effective, cost efficient method is found. Apparent bad news came to the Refuge after two severe winters in 2010 and 2011; it was thought that the moth had died out due to the cold.

Brown Lygodium Moth

Bio-control agent Brown Lygodium moth.

Therefore, it was great news when the moth was recently discovered six miles from the original release sites. The moth had established on sites with limited diversity of plant species other than the Old World Climbing Fern. Researchers now believe that other insect species, especially fire ants, could have been responsible for preventing establishment of the Neo moth on the original tree island sites, which had a wider variety of plants and insects present. In some sites the moth is not only defoliating the fern and reducing spore production, but appears to be killing the plant. This is more good news for the Refuge and the fight against invasive species and very bad news for Old World Climbing Fern!