Journal of Economic Entomology (1996) 89, 1325-1331

Richard E. Shade, Laurie W. Kitch, Paul Mentzer and Larry L. Murdock (1996)
Selection of a cowpea weevil (Coleoptera: Bruchidae) biotype virulent to cowpea weevil resistant landrace TVu 2027
Journal of Economic Entomology 89 (5), 1325-1331
Abstract: Studies of cowpea weevil, Callosobruchus maculatus (F.), larvae in seeds of resistant (Cowpea landrace) TVu 2027 and susceptible 'California Blackeye No. 5' (CB5) revealed that 10-15% of the Cowpea weevil population develop at the same rate in TVu 2027 as in CB5 seeds. When adults having the same developmental rates on TVu 2027 as CB5 were selected and intercrossed for 8 generations, there was no significant difference in within-seed developmental time between the selected and unselected populations. Therefore, these rapidly developing individuals do not represent an emerging cowpea weevil biotype but may result from a chance avoidance of the resistance factor by individual cowpea weevil larvae, coupled with seed-to-seed variation for the resistance factor. However, we were able to develop a cowpea weevil biotype virulent to TVu 2027 by selecting and intercrossing the most rapidly developing individuals over 53 cowpea weevil generations. After 53 generations of selection the cowpea weevil biotype developed as rapidly in TVu 2027 seeds as did the unselected population in susceptible CB5 seeds. The biotype developed at the same rate on cowpea weevil-resistant KNS and KNW lines as on TVu 2027, confirming that the basis of resistance is the same in all 3 lines. Also, biotype virulence to KNS and KNW suggests that the biotype can be used to identify cowpea lines with the TVu 2027 source of resistance.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Richard E. Shade, Larry L. Murdock

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Callosobruchus maculatus	Stored legumes