Author
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Charlet, Laurence |
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Submitted to: Great Plains Sunflower Insect Workshop Proceedings
Publication Type: Proceedings Publication Acceptance Date: 9/15/2000 Publication Date: N/A Citation: N/A Interpretive Summary: The sunflower midge emerged as an insect pest of sunflower in 1971. It has been a sporatic pest since then causing severe crop loss as recently as 1997 and 1998. The results from insecticide trials conducted between 1980 and 1983 revealed the lack of effectiveness for reducing midge damage from a chemical control strategy. The approaches had included many different types and classes of insecticides, utilized both systemic and foliar applications, incorporated single and multiple applications, and investigated timing based on both midge biology and plant growth stage. The failure of insecticides to adequately control the sunflower midge was probably a result of either inaccurate timing for the spray application to kill the adults or the expansion of the buds so that adults were exposed to untreated surfaces rather than the chemical itself. Laboratory trials have shown that the midge is very susceptible to a variety of insecticides. In addition, the material may not be contacting the larvae since they are located inside the bracts or at the base of the disk flowers. Additional insecticidal trials utilizing different strategies to control the sunflower midge are planned in 2000. Little information is available on the natural enemies of the sunflower midge. A wasp parasitoid of the midge was first reported in 1976 and described as Inostemma sp. I have been rearing overwintering sunflower midge larvae since 1997 and have recovered both males and females of Inostemma sp. Specimens of Inostemma sp. have recently been examined and are described as Inostemma new species near californica. Future research on the sunflower midge natural enemies will focus on a survey of both cultivated and native sunflower to search for additional parasitoids and to investigate the biology of this wasp. Technical Abstract: The sunflower midge emerged as an insect pest of sunflower in 1971. It has been a sporatic pest since then causing severe crop loss as recently as 1997 and 1998. The results from insecticide trials conducted between 1980 and 1983 revealed the lack of effectiveness for reducing midge damage from a chemical control strategy. The approaches had included many different types and classes of insecticides, utilized both systemic and foliar applications, incorporated single and multiple applications, and investigated timing based on both midge biology and plant growth stage. The failure of insecticides to adequately control the sunflower midge was probably a result of either inaccurate timing for the spray application to kill the adults or the expansion of the buds so that adults were exposed to untreated surfaces rather than the chemical itself. Laboratory trials have shown that the midge is very susceptible to a variety of insecticides. In addition, the material may not be contacting the larvae since they are located inside the bracts or at the base of the disk flowers. Additional insecticidal trials utilizing different strategies to control the sunflower midge are planned in 2000. Little information is available on the natural enemies of the sunflower midge. A wasp parasitoid of the midge was first reported in 1976 and described as Inostemma sp. I have been rearing overwintering sunflower midge larvae since 1997 and have recovered both males and females of Inostemma sp. Specimens of Inostemma sp. have recently been examined and are described as Inostemma new species near californica. Future research on the sunflower midge natural enemies will focus on a survey of both cultivated and native sunflower to search for additional parasitoids and to investigate the biology of this wasp. |
