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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #200157
Title: Rubidium marking to detect pest and predator dispersal from corn into sorghum and cotton in Georgia

Author
item Tillman, Patricia - Glynn
item Prasifka, Jarrad
item HEINZ, K - TEXAS A&M UNIVERSITY

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2006
Publication Date: 7/31/2007
Citation: Tillman, P.G., Prasifka, J.R., Heniz, K.M. 2007. Rubidium marking to detect dispersal of pest and predator from corn into sorghum and cotton in Georgia. Journal of Entomological Science. 42(3): 383-391.

Interpretive Summary: Populations of the pest, the corn earworm, and its predator, the minute pirate bug, build up early-season in corn and usually occur in sorghum and cotton mid-to-late season. The question is do both of these insect species disperse from corn into sorghum and cotton? This field study evaluated marking both the pest and its predator with rubidium chloride (RbCl) in corn to detect their Populations of the pest, the corn earworm, and its predator, the minute pirate bug, build up early-season in corn and usually occur in sorghum and cotton mid-to-late season. The question is do both of these insect species disperse from corn into sorghum and cotton? This field study evaluated marking both the pest and its predator with rubidium chloride (RbCl) in corn to detect their dispersal from corn into sorghum and cotton. Small sorghum and cotton plots were planted at the common boundary of a commercial corn and cotton field, and the cotton field adjacent to these interface plots was divided into cotton field plots. Foliar solutions of RbCl were applied to corn at two field sites. Both corn earworm eggs and minute pirate bug females were successfully marked in corn treated with RbCl, and percentage of marked insects for both species in sorghum and cotton ranged from 15-33%. Data on rubidium-marked insects indicated that corn earworm and minute pirate bug females dispersed into sorghum and cotton.

Technical Abstract: This field study evaluated marking both the pest Helicoverpa zea (Boddie) and its predator Orius insidiosus (Say) with rubidium chloride (RbCl) in corn to detect their dispersal from corn into sorghum and cotton. Small sorghum and cotton plots were planted at the interface, or common boundary, of commercial corn and cotton field. The cotton field adjacent to these interface plots was divided into cotton field plots. Foliar solutions of RbCl were applied to corn at field site 1 when the ears were infested with 4th through 6th-instars of H. zea and at site 2 when corn silks were infested with eggs and 1st-instars of H. zea and nymphs and adults of O. insidiosus. Insects were collected at various times after RbCl application from the sorghum interface plots, cotton interface plots, and cotton field plots. Both H. zea eggs and O. insidiosus females were successfully marked in corn treated with RbCl, and percentage of marked insects for both species in sorghum and cotton ranged from 15-33%. Data on rubidium-marked insects indicated that H. zea females from the generation feeding on rubidium-treated corn dispersed into sorghum interface plots at both treated sites and into cotton interface plots at one site and that O. insidiosus females dispersed from corn into sorghum interface plots and cotton field plots at one site.