Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2007
Publication Date: 12/1/2007
Citation: White, W.H., Reagan, T.E., Carlton, C., Akbar, W., Beuzelin, J.M. 2007. Elachista saccharella (Busck) (Lepidoptera: Elachistidae), A Leafminer Infesting Sugarcane in Louisiana. Florida Entomologist. 90(4):792-794. Interpretive Summary: The threat posed by the introduction or migration of new insect pests represents a major concern for agricultural interest worldwide. These new insects can become important economic pests in their new environment or become merely an incidental insect with no economic implications. In July of 2006 we discovered a new insect associated with sugarcane in Louisiana. This insect was identified as the sugarcane leafminer. As a group, leafminers are important pests of numerous agricultural commodities worldwide. This particular leafminer is a minute moth that makes a distinct leafmine that terminates in a blotch-shaped tunnel. Twenty sugarcane producing parishes were surveyed for the presence of the leafminer with notes taken on the position of leafmines on the plant, numbers of leafmines per plant, and frequency of parasitism by natural enemies. We found the leafminer in 17 of the 20 parishes surveyed, but only 11% of the 1,600 stalks sampled harbored a leafminer. Most of the leafmines were found on older leaves and almost three quarters of the leafminers were either parasitized or had been parasitized; an indication of very high mortality in the immature stages of the leafminer. For these reasons, we do not perceive this insect to be an economic threat to Louisiana sugarcane. Although only an incidental insect, finding the leafminer does remind regulatory personnel and sugarcane growers of the need to always be vigilante for new insect pest incursions as the next new insect may have the potential of becoming a serious economic threat.
Technical Abstract: The leafminer, Elachista saccharella (Busck) (Lepidoptera: Elachistidae) was found in Louisiana on 12 July 2006 and documented as a new distribution record for Louisiana and the south-central United States and represents a significant range extension for the species. Elachista saccharella was first reported in sugarcane in the U.S. in Florida in 1982. We initiated a survey of the sugarcane areas of Louisiana for the presence of the leafminer after finding one in Terrebonne Parish in the summer of 2006. The leafminer was found in 17 of 20 sugarcane producing parishes surveyed. Although distributed generally throughout the sugarcane growing region, only 11% of the stalks sampled (n=1600) were infested and 72% of the samples collected were parasitized. The lesions made by the leafminer constituted only 3% of the total leaf area and were usually detected on older leaves. For these reasons, it does not appear that E. saccharella will be an economic threat to sugarcane in Louisiana. This finding does has significance as it reminds both regulatory agencies and grower groups to remain vigilant for new pests and to have contingency plans available should an important introduction occur.