Journal of Economic Entomology (2005) 98, 1-8

James D. Oleson, Yong-Lak Park, Timothy M. Nowatzki and Jon J. Tollefson (2005)
Node-injury scale to evaluate root injury by corn rootworms (Coleoptera: Chrysomelidae)
Journal of Economic Entomology 98 (1), 1-8
Abstract: Corn rootworm larval feeding on corn roots can significantly reduce grain yield by interfering with photosynthetic rates, limiting the uptake of water and nutrients, and by increasing the plant's susceptibility to lodging. Of the techniques developed to measure the efficacy of corn rootworm larval control tactics, root damage ratings have generally been adopted as the standard because sampling roots is relatively efficient. Historically, the primary scales used for scoring root injury from corn rootworm larval feeding have been the 1-6 and 1-9 scales. A critical deficiency of those scales, however, is that each increase in a root-rating score does not reflect a linear increase in the actual amount of injury to the root system. This results in injury scores that are expressed qualitatively. We developed the node-injury scale to more accurately quantify corn rootworm larval injury based on the proportion of nodal roots that contain feeding injury. With the node-injury scale, the relationship between the numerical scale and the amount of root injury is linear and intuitive. In this article, we describe the node-injury scale, discuss sampling issues to consider when using the scale, and suggest the minimum node-injury score that causes economic damage under varying degrees of environmental stress.
(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): Yong-Lak Park

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diabrotica virgifera	Maize/corn (Zea mays)
	Diabrotica (genus)	Maize/corn (Zea mays)