ARS | Publication request: Varietal susceptibility to the corn wireworm Melanotus Communis (Coleoptera:>Elateridae) in sugarcane

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 9, 2012
Publication Date: May 13, 2013
Citation: Larson, N.A., Nuessly, G.S., Cherry, R., Glaz, B.S. 2013. Varietal susceptibility to the corn wireworm Melanotus Communis (Coleoptera:>Elateridae) in sugarcane. Journal of Pest Science. 86:91-98.

Interpretive Summary: More sugar is produced by Florida sugarcane growers than by sugarcane or sugar beet growers in any other state in the U.S. The major insect pest of sugarcane in Florida is the corn wireworm (Melanotus communis Gyll.). The wireworm is controlled primarily through the application of a soil insecticide at planting. However, other control measures are needed because the insecticides being used, known as organophosphate insecticides, are being phased out by EPA regulations. Planting sugarcane after flooded rice or after fallow flooding are effective control measures but are not feasible for much of the sugarcane planted in Florida. In addition, new research shows that scouting fields prior to planting can help reduce the use of organophosphate insecticides to control wireworms. The purpose of this 2-year greenhouse study was to determine if there were differences among 11 sugarcane varieties in their ability to tolerate or resist damage from the corn wireworm. In addition, a variety that is a wild relative of sugarcane (Saccharum spontaneum) was included in these tests. In December 2009 and January 2011, these varieties were planted in separate containers in a greenhouse. Ten containers of each variety were planted each year, five containers had no wireworms and the other five containers were heavily infested with wireworms. After planting, number of emerged plants was counted and at the end of each experiment (about 12 weeks after planting), above and below ground plant biomasses were determined. We found that most of the varieties had reduced plant counts and biomass due to wireworm infestation. However, several of the varieties did not have reduced numbers of plants or reduced biomass; these varieties tolerated the wireworm infestations by emerging soon after planting and rapidly developing a high number of tillers. This new information indicates that along with scouting, variety selection can be an important component of an integrated cultural program to control wireworms with reduced use of insecticides for fields in which it is not feasible to flood prior to planting.

Technical Abstract: Wireworms (larval Elateridae) reduce the stand of newly planted sugarcane (complex hybrid of Saccharum spp.) directly by damaging growing points and indirectly by facilitating disease introduction. No research has evaluated resistance or tolerance of sugarcane genotypes grown in Florida. Eleven genotypes of sugarcane and a S. spontaneum genotype were subjected to corn wireworm, Melanotus communis (Gyllenhall) (Coleoptera: Elateridae), in a greenhouse experiment to evaluate potential host plant resistance. The experiment was designed to measure the effects of wireworms on the first 90 days of growth. Sugarcane stalk sections were planted in trays of soil with and without wireworms in 2010 and 2011. Stand count, dry weight, and percentage of nodes damaged were evaluated. Wireworms reduced stand and dry weight by 40-60%. Several genotypes were able to produce acceptable stands in wireworm-infested trays by emerging quickly and producing many tillers. CP 88-1762, CP 89-2143, and CP 03-1912 did not suffer statistically significant losses of stand or biomass due to wireworms in either year. Our findings suggest that genotype resistance should be considered as an important component of an integrated program aimed at reducing the use of insecticides to control wireworms in sugarcane.