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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #134464
Title: IMPACT OF PLANTING DATE ON SUNFLOWER BEETLE (COLEOPTERA: CHRYSOMELIDAE) INFESTATION, DAMAGE, AND PARASITISM IN CULTIVATED SUNFLOWER

Author
item CHARLET, LAURENCE
item KNODEL, JANET - NORTH DAKOTA STATE UNIV.

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2003
Publication Date: 6/30/2003
Citation: CHARLET, L.D., KNODEL, J.J. IMPACT OF PLANTING DATE ON SUNFLOWER BEETLE (COLEOPTERA: CHRYSOMELIDAE) INFESTATION, DAMAGE, AND PARASITISM IN CULTIVATED SUNFLOWER. JOURNAL OF ECONOMIC ENTOMOLOGY. 2003. V. 96 (3). P. 706-713.

Interpretive Summary: The sunflower beetle is the major defoliating pest of sunflower. Planting date was evaluated as a potential management tool in a variety of production regions throughout North Dakota from 1997 to 1999, for its impact on sunflower beetle adult and larval population density, defoliation caused insect feeding, seed yield, oil content, and larval parasitism in cultivated sunflower. Results from this three year study revealed that sunflower beetle adult and larval populations decreased as planting date was delayed. The data was consistent even though planting dates were not the same at all locations. Delayed planting also reduced defoliation of plants caused by the feeding of both adults and larvae, which is consistent with the lower numbers of the beetles present in the later seeded plots. Even a planting delay of only one week was sufficient to significantly reduce feeding damage to the sunflower plant. Yield reduction caused by the leaf destruction of the sunflower beetle adults and larvae was clearly evident in the first year of the multi-year investigation. The other component of sunflower yield, the oil content, did not appear to be influenced by beetle feeding. The fly parasite of the sunflower beetle larvae appeared to be a significant mortality factor at most locations regardless of the dates of planting, and was able to attack and parasitize the beetle at varied larval densities. The results of this investigation showed the potential of planting date as an effective integrated pest management tactic to reduce sunflower beetle adults, larvae, and their resulting defoliation, and to potentially prevent yield loss in cultivated sunflower. In addition, altering planting dates was compatible with biological control of the beetle, because delaying the planting date did not reduce the effectiveness of the parasitic fly which attacks the beetle larvae.

Technical Abstract: The sunflower beetle, Zygogramma exclamationis (F.), is the major defoliating pest of sunflower (Helianthus annuus L.). Planting date was evaluated as a potential management tool in a variety of production regions throughout North Dakota from 1997 to 1999, for its impact on sunflower beetle population density of both adults and larvae, defoliation caused by both feeding stages, seed yield, oil content, and larval parasitism in cultivated sunflower. Results from this three year study revealed that sunflower beetle adult and larval populations decreased as planting date was delayed. The data was consistent even though planting dates were not the same at all locations. Delayed planting also reduced defoliation of plants caused by the feeding of both adults and larvae, which is consistent with the lower numbers of the beetles present in the later seeded plots. Even a planting delay of only one week was sufficient to significantly reduce feeding damage to the sunflower plant. Yield reduction caused by the leaf destruction of the sunflower beetle adults and larvae was clearly evident in the first year of the multi-year investigation. The other component of sunflower yield, the oil content, did not appear to be influenced by beetle feeding. The tachinid parasitoid, Myiopharus macellus (Rheinhard), appeared to be a significant mortality factor of sunflower beetle larvae at most locations regardless of the dates of planting, and was able to attack and parasitize the beetle at varied larval densities. The results of this investigation showed the potential of planting date as an effective integrated pest management tactic to reduce sunflower beetle adults, larvae, and their resulting defoliation, and to potentially prevent yield loss in cultivated sunflower. In addition, altering planting dates was compatible with biological control of the beetle, because delaying the planting date did not reduce the effectiveness of the parasitic fly, M. macellus, which attacks the sunflower beetle larvae.