Fig 1.
(a) Location of Kume Island, Okinawa, Japan. (b) Predicted distribution area of C. formicarius in Kume island (areas where male weevils have been found in trap surveys are blacked out). Created by processing a base map (Geospatial Information Authority of Japan).
Fig 2.
Number of sterile weevils C. formicarius released per week on Kume Island from 1999 to 2012.
Black bars represent aerial releases and white bars represent ground releases. Short breaks in the release of sterile insects were implemented (January-February 2002, January-March 2004, January-March 2005, August 2005-March 2006, December 2007-March 2008) to allow for the detection of remaining areas of occurrence of C. formicarius using sex pheromone traps. The black arrow indicates the initiation of the release of the PE strain for SIT application in January 2010. Until July 2001, only males were released. However, thereafter, both sexes were released.
Fig 3.
Cylinder-type sex pheromone trap used after April 1998.
Traps were fitted with a rubber septum or ring containing 0.1 mg of a synthetic pheromone as an attractant. Insecticide (DDVP) was added to prevent the escape of the trapped insects.
Fig 4.
Number of captured male weevils C. formicarius per thousand traps per day in Kume Island.
Black circles indicate wild weevils (unmarked) in the MAT and SIT application area. White triangles indicate wild weevils in the non-MAT application areas. Gray circles indicate marked weevils (from January 2010, we used the phenotypic marker; the piceous elytra of the PE strain) in the SIT application area. The black arrow indicates the initiation of the release of the PE strain for SIT application in January 2010.
Fig 5.
Infestation rate of weevils C. formicarius on wild hosts in Kume Island.
Black circles indicate the % infection in MAT and SIT application areas and white circles indicate % infection in the non-MAT application areas.