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Introduction of an opportunistic bacterial cotton pathogen into bolls by the southern green stink bug (Nezara viridula L.) E. G. Medrano, J. F. Esquivel, and A. A. Bell USDA-ARS-SPARC, College Station, TX
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Seed Rot of South Carolina Cotton Emerging disease First reported during 1999 in South Carolina Yield losses from 10 to 15% Spread to fields located throughout southeastern Cotton Belt states
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Disease Symptoms Disease symptoms manifested inside bolls Exterior carpel of immature diseased bolls are non-symptomatic Cross-sections of immature diseased bolls reveal necrotic seed and discolored fiber
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Previous Work Role of Pantoea agglomerans in opportunistic bacterial seed and boll rot of cotton (Gossypium hirsutum) grown in the field ( Medrano and Bell, 2007, Journal of Applied Microbiology- 102, 134-143 ) Transmission of cotton seed and boll rotting bacteria by the southern green stink bug, Nezara viridula L. (Heteroptera: Pentatomidae) ( Medrano, Esquivel, and Bell, 2007, Journal of Applied Microbiology- in press )
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Boll inoculated with P. agglomerans Rif (PaRif )* *28-gauge needle simulating insect puncture (Medrano & Bell 2007) rr
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Comparison of diseased greenhouse* and field cotton *28-gauge needle simulating insect puncture (Medrano & Bell 2007)
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Cotton Insect Pests Piercing/sucking mouthparts used for feeding on developing fruit Includes stink bugs, lygus, and cotton fleahoppers
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Insect Transmission Study Method Lab-reared southern green stink bugs (SGSB) were raised on fresh green beans (not sterile) that were replenished every 2 days. Bacterial exposure to insects: Sterilized Green Bean PaRif r H2OH2O Provided to insect for 2 days Soaked 2 min in: or
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Insect Transmission Study Method (cont’d) Cotton boll harvesting: -Evidence of insect feeding was determined after boll exposure to insects. -Bolls were surface sterilized and then seed and lint tissue were aseptically collected, triturated, and then dilution plated on media with/without Rif. Exposure of cotton bolls to insects: Weeks Post Anthesis: 2 wks Caged 2 days Harvested after: 2 wks
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Cotton bolls exposed to SGSB PaRif + r PaRif - r
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Cotton bolls exposed to SGSB PaRif + r PaRif - r
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Cotton bolls exposed to SGSB PaRif + r PaRif - r
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Cotton bolls exposed to SGSB PaRif + r PaRif - r
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