ARS | Publication request: Rootstock weevils: out of sight, out of mind or emerging pests

Submitted to: Sugar Journal
Publication Type: Trade Journal
Publication Acceptance Date: April 30, 2012
Publication Date: June 20, 2012
Citation: White, W.H., Carlton, C. 2012. Rootstock weevils: out of sight, out of mind or emerging pests. Sugar Journal. 75(1):28-29.

Technical Abstract: In Louisiana, rootstock weevils form a pest complex comprised of three species of curculionid beetles: Apinocis subnudus (Buchanan), A. deplanatus (Casey), and A. blanditus (Casey). This complex was first reported as a single species, Anacentrinus subnudus, known to be associated with sugarcane in Louisiana at least back to 1910. At that time it was considered an insect of minor importance until 1931, when a very serious weevil infestation was found near Arnaudville, LA. Much of our knowledge about the distribution and biology of rootstock weevils comes from the early literature. From that literature, the amount of damage to sugarcane that can be attributed to rootstock weevils is difficult to assess. Heavily damaged sugarcane can appear drought stressed. Feeding by weevils is also thought to be a point of entry for soil pathogens. We have successfully used pitfall traps in determining the species composition of the pest complex. We have also begun to look at seasonal distribution and abundance of weevils throughout the sugarcane growing area. Initial trapping shows that now, as in 1931, rootstock weevils are found throughout the cane growing area of Louisiana. And finally, we are beginning to rear the weevils in the laboratory as a first step in conducting controlled experiments in disease transmission and possibly determining damage threshold levels. However, how much longer rootstock weevils will continue to be a concern remains to be seen, but preemptive research into the natural history of these potential pests will put us in a better position to develop effective management strategies should they prove necessary.