Skip to main content
ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Publications at this Location » Publication #251047

Title: Biological Control of Old World climbing fern, Lygodium microphyllum - Recent progress with the brown lygodium moth

Author
item Boughton, Anthony
item Center, Ted

Submitted to: Florida Exotic Pest Plant Council
Publication Type: Other
Publication Acceptance Date: 3/18/2010
Publication Date: 4/6/2010
Citation: . Florida Exotic Pest Plant Council.

Interpretive Summary: Old World climbing fern, Lygodium microphyllum is one of the most serious invasive weeds impacting natural areas in southern and central Florida. Management of this weed using traditional methods has proved difficult and expensive, and has prompted efforts to develop biological control options for this damaging weed. The brown lygodium moth, Neomusotima conspurcatalis was the first biological control agent to establish field populations on lygodium in Florida. This insect was first released in Jonathan Dickinson State Park in Martin County, Florida in early 2008 and rapidly developed large populations that caused substantial defoliation damage to lygodium at release sites. During the first 8 months following releases, caterpillar-induced defoliation reduced ground cover of lygodium at release sites by about 53% from an initial 49% to 20% at the end of 2008. Over this same period, ground cover of lygodium at control sites, where the moth was not present, remained relatively static at about 43%. The moth remained present at release sites during 2009, although populations were smaller than those observed during late 2008. When vegetation was next measured in early 2010, lower feeding pressure by the moth had allowed some regrowth of the weed to occur and lygodium ground cover at release sites had recovered to 27%, although this was still only about half that present before the moth was released. Control plots were colonized by the moth during 2009 and suffered heavy defoliation, reducing lygodium cover by about 47% from the previously observed average of 43% seen in early 2009 down to 22% in early 2010. Observations confirmed that the brown lygodium moth, which is primarily a tropical insect in its native range, is adversely affected by cold weather during the winter season in south Florida. We also suspect that parasitism of caterpillars by native parasitic wasps may account for some of the declines in moth populations observed after 2008. New releases of a second biocontrol agent, the lygodium moth, Austromusotima camptozonale, are planned for 2010. A third biocontrol agent, the lygodium sawfly, is currently undergoing regulatory evaluation and research continues in Australia on several stem-boring moths that appear to have great potential for lygodium biocontrol.

Technical Abstract: Old World climbing fern, Lygodium microphyllum is one of the most serious invasive weeds impacting natural areas in southern and central Florida. Management of this weed using traditional methods has proved difficult and expensive, and has prompted efforts to develop biological control options for this damaging weed. The brown lygodium moth, Neomusotima conspurcatalis was the first biological control agent to establish field populations on lygodium in Florida. This insect was first released in Jonathan Dickinson State Park in Martin County, Florida in early 2008 and rapidly developed large populations that caused substantial defoliation damage to lygodium at release sites. During the first 8 months following releases, caterpillar-induced defoliation reduced ground cover of lygodium at release sites by about 53% from an initial 49% to 20% at the end of 2008. Over this same period, ground cover of lygodium at control sites, where the moth was not present, remained relatively static at about 43%. The moth remained present at release sites during 2009, although populations were smaller than those observed during late 2008. When vegetation was next measured in early 2010, lower feeding pressure by the moth had allowed some regrowth of the weed to occur and lygodium ground cover at release sites had recovered to 27%, although this was still only about half that present before the moth was released. Control plots were colonized by the moth during 2009 and suffered heavy defoliation, reducing lygodium cover by about 47% from the previously observed average of 43% seen in early 2009 down to 22% in early 2010. Observations confirmed that the brown lygodium moth, which is primarily a tropical insect in its native range, is adversely affected by cold weather during the winter season in south Florida. We also suspect that parasitism of caterpillars by native parasitic wasps may account for some of the declines in moth populations observed after 2008. New releases of a second biocontrol agent, the lygodium moth, Austromusotima camptozonale, are planned for 2010. A third biocontrol agent, the lygodium sawfly, is currently undergoing regulatory evaluation and research continues in Australia on several stem-boring moths that appear to have great potential for lygodium biocontrol.