Author
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Vick, Brady |
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Submitted to: Great Plains Sunflower Insect Workshop Proceedings
Publication Type: Proceedings Publication Acceptance Date: 4/13/2000 Publication Date: N/A Citation: N/A Interpretive Summary: The sunflower midge was first discovered in 1971 and was identified as the cause of serious damage to the heads of cultivated sunflower in North Dakota and northwestern Minnesota. Symptoms were severe gnarling of the heads or cupping, resulting in reduced seed set and in the worst case, complete loss of seed set. Although the sunflower midge is distributed throughout the Great Plains growing region of cultivated sunflower, it has only been a serious economic pest in the northern production area of North and South Dakota and northwestern Minnesota. This study aimed to establish whether sunflower heads emit volatile compounds that attract the sunflower midge. Such compounds would serve as kairomones, compounds beneficial to the midge but harmful to the sunflower. In one experiment sunflower bud volatile compounds were used in an insect trap. However, the trap attracted several insect species, and a control trap with water was just as effective as the trap containing sunflower volatile compounds. In a second experiment using an olfactometer, adult sunflower midge were attracted down a tube to a young sunflower bud, suggesting that they were sensitive to a chemical cue from the sunflower bud. Although this experiment needs to be repeated, the initial results indicate the possible role of a volatile chemical attractant that guides the sunflower midge to a young sunflower bud. Further research is underway to repeat the experiment and establish whether or not this hypothesis is correct. If chemical attractants of the sunflower midge can be identified, it may be possible to use them to monitor the severity of midge infestations, or as a means to control their populations. Technical Abstract: The sunflower midge was first discovered in 1971 and was identified as the cause of serious damage to the heads of cultivated sunflower in North Dakota and northwestern Minnesota. Symptoms were severe gnarling of the heads or cupping, resulting in reduced seed set and in the worst case, complete loss of seed set. Although the sunflower midge is distributed throughout the Great Plains growing region of cultivated sunflower, it has only been a serious economic pest in the northern production area of North and South Dakota and northwestern Minnesota. This study aimed to establish whether sunflower heads emit volatile compounds that attract the sunflower midge. Such compounds would serve as kairomones, compounds beneficial to the midge but harmful to the sunflower. In one experiment sunflower bud volatile compounds were used in an insect trap. However, the trap attracted several insect species, and a control trap with water was just as effective as the trap containing sunflower volatile compounds. In a second experiment using an olfactometer, adult sunflower midge were attracted down a tube to a young sunflower bud, suggesting that they were sensitive to a chemical cue from the sunflower bud. Although this experiment needs to be repeated, the initial results indicate the possible role of a volatile chemical attractant that guides the sunflower midge to a young sunflower bud. Further research is underway to repeat the experiment and establish whether or not this hypothesis is correct. If chemical attractants of the sunflower midge can be identified, it may be possible to use them to monitor the severity of midge infestations, or as a means to control their populations. |
