Efficacy of spinosad bait sprays to control Mediterranean and Caribbean fruit flies (Diptera: Tephritidae) in commercial citrus in Florida

A serious infestation of Mediterranean fruit fly in Florida in 1997 and 1998 led to the widespread aerial and foliar application of malathion-bait sprays. Public concerns over property damage, environmental impact and public health led to the immediate need and acceptability of alternative pesticide/bait combinations. Preliminary work with spinosad, a derivative of a soil microorganism developed by Dow AgroSciences, in combination with a new bait (SolBait) showed promise. To ensure that this product would be effective in Florida for fruit fly control, three field tests were conducted using aerial and/or foliar applications. Results indicated that sprays with spinosad-SolBait provided comparable and significant control levels for sterile Mediterranean and Caribbean fruit flies in comparison to standard malathion with NU-LURE or SolBait treatments by aerial or foliar application. In one test, honey bees and hives were exposed to sprays in the treatment area and no significant treatment differences were observed in hive condition or brood. Insufficient data on effects of treatments on naturally occurring and introduced beneficial insects were collected for statistical analysis but it appears no harmful effects were observed.