Weed Science (2004) 52, 1034-1038

David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra and John Lindquist (2004)
Common lambsquarters (Chenopodium album) interference with corn across the northcentral United States
Weed Science 52 (6), 1034-1038
Abstract: Variation in crop-weed interference relationships has been shown for a number of crop-weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the northcentral United States. Two coefficients (I and A) of a rectangular hyperbola were estimated for each data set using nonlinear regression analysis. The I coefficient represents corn yield loss as weed density approaches zero, and A represents maximum percent yield loss. Estimates of both coefficients varied between years at Wisconsin, and I varied between years at Michigan. When locations with similar sample variances were combined, estimates of both I and A varied. Common lambsquarters interference caused the greatest corn yield reduction in Michigan (100%) and had the least effect in Minnesota, Nebraska, and Indiana (0% yield loss). Variation in I and A parameters resulted in variation in estimates of a single-year economic threshold (0.32 to 4.17 plants m^-1 of row). Results of this study fail to support the use of a common yield loss-weed density function for all locations.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): David W. Fischer, John L. Lindquist, James J. Kells, Gregg A. Johnson

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Chenopodium album (weed)	Maize/corn (Zea mays)	U.S.A. (mid N)
	Chenopodium album (weed)	Maize/corn (Zea mays)	U.S.A. (NE)