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United States Department of Agriculture

Agricultural Research Service

Title: Corn Rootworm Sampling in Maize Roots and Surrounding Soil Cores

Authors
item Hammack, Leslie
item Ellsbury, Michael
item Roehrdanz, Richard
item Pikul Jr, Joseph

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 2002
Publication Date: November 17, 2002
Citation: HAMMACK, L., ELLSBURY, M.M., ROEHRDANZ, R.L., PIKUL JR, J.L. CORN ROOTWORM SAMPLING IN MAIZE ROOTS AND SURROUNDING SOIL CORES. ENTOMOLOGICAL SOCIETY OF AMERICA ANNUAL MEETING. 2002. Paper No. D0670.

Technical Abstract: Larvae were collected yearly from 1999-2001 to correlate western corn rootworm (WCR) recovery from maize root systems with that from surrounding soil cores (19-cm diameter and depth)and to verify that head capsule width is a useful indicator of larval instar in field populations of both WCR and northern corn rootworm (NCR). Maize root systems were pressure washed to remove surface soil for better standardization of the sampling unit and then dried to maneuver larvae from roots into water traps for collection. Root-surface washes were pooled with corresponding soil cores and stored frozen. Larvae were recovered from each soil core via standard sieving and flotation methods. While fewer WCR were found in maize roots than in soil cores surrounding roots, the two population estimates were significantly correlated (y=3.89x + 16.31, r=0.60, N=81, P<0.0001), and larvae were vastly easier to sample from roots given the amount of macroorganic matter in our soil cores. Peaks in a frequency distribution of head capsule widths from field grown WCR (N>800) matched those previously reported by instar for small numbers of mostly laboratory reared specimens. Frequency of head-capsule widths from feral NCR (N>500) displayed three peaks at sizes similar to those of WCR, but there was some overlap between NCR peaks not seen in WCR.

Last Modified: 12/21/2014
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