@article{reisig_suits_burrack_bacheler_dunphy_2017, title={Does florivory by Helicoverpa zea cause yield loss in soybeans?}, volume={110}, ISSN={["1938-291X"]}, DOI={10.1093/jee/tow312}, abstractNote={Abstract Helicoverpa zea (Boddie), corn earworm, is a damaging insect pest of many crops, including soybeans. An economic threshold for soybeans during the pod-filling stages exists to prevent economic damage to seeds. However, the impact of florivory (flower feeding) by H. zea larvae on seed yield is poorly understood and there is no economic threshold for flowering-stage soybeans. Four small plot experiments were conducted in North Carolina during 2011 and 2012 to assess the impact of H. zea feeding during the flowering stages of determinate soybeans on various yield components. Helicoverpa zea densities were manipulated with insecticides and various planting dates of soybeans and monitored weekly. Helicoverpa zea naturally infested the plots after flowering began and were allowed to feed until R3; they were eliminated from all plots from R3 to maturity. In some sites, H. zea densities exceeded the podding economic threshold during the flowering stages, but yield did not differ among treatments. During 2012, florivory from H. zea was measured directly by counting injured flowers. There was a negative yield relationship between both injured flower number and cumulative flower number. Moreover, H. zea densities were related to both a decrease in cumulative flowers and an increase in injured flowers, even though a direct linkage between H. zea density and yield loss was not observed. Without knowing the preferred tissue types and performance of early-instar larvae on soybeans, it is possible that H. zea density may not be the best measurement for developing an economic threshold in flowering soybeans.}, number={2}, journal={J. Econ. Entomol}, publisher={Oxford University Press (OUP)}, author={Reisig, D. and Suits, R. and Burrack, H. and Bacheler, J. and Dunphy, J.E.}, year={2017}, pages={464–470} }
 @article{place_reberg-horton_dunphy_smith_2009, title={Seeding Rate Effects on Weed Control and Yield For Organic Soybean Production}, volume={23}, ISSN={["1550-2740"]}, DOI={10.1614/WT-08-134.1}, abstractNote={The organic grain sector is one of the fastest growing sectors of the organic market, but farmers in the mid-Atlantic cannot meet the organic grain demand, including the demand for organic soybean. Weed management is cited by farmers as the largest challenge to organic soybean production. Recent soybean population studies show that lower seeding rates for genetically modified organism soybean farmers provide maximum economic return due to high seed technology fees and inexpensive herbicides. Such economic analysis may not be appropriate for organic soybean producers due to the absence of seed technology fees, stronger weed pressures, and price premiums for organic soybean. Soybean seeding rates in North Carolina have traditionally been suggested at approximately 247,000 live seeds/ha, depending on planting conditions. Higher seeding rates may result in a more competitive soybean population and better economic returns for organic soybean producers. Experiments were conducted in 2006 and 2007 to investigate seeding rates of 185,000, 309,000, 432,000, and 556,000 live seeds/ha. All rates were planted on 76-cm row spacing in organic and conventional weed management systems. Increased soybean seeding rates reduced weed ratings at three of the five sites. Increased soybean seeding rates also resulted in higher yield at three of the four sites. Maximum economic returns for organic treatments were achieved with the highest seeding rate in all sites. Results suggest that seeding rates as high as 556,000 live seeds/ha may provide organic soybean producers with better weed control, higher yield, and increased profits.}, number={4}, journal={WEED TECHNOLOGY}, publisher={Cambridge University Press (CUP)}, author={Place, George T. and Reberg-Horton, Samuel Chris and Dunphy, Jim E. and Smith, Adam N.}, year={2009}, pages={497–502} }
 @article{koenning_creswell_dunphy_sikora_mueller_2006, title={Increased occurrence of target spot of soybean caused by Corynespora cassiicola in the southeastern United States.}, volume={90}, ISSN={["0191-2917"]}, DOI={10.1094/PD-90-0974C}, abstractNote={ Target spot of soybean (Glycine max (L.) Merr.) caused by Corynespora cassiicola (Berk. & Curt.), although found in most soybean-growing countries, is considered to be a disease of limited importance (1) and has never been reported to cause soybean yield loss in the southeastern United States (2,3). Soybean plants submitted to the North Carolina Plant Disease and Insect Clinic (NCPDIC) in August 2004 from Beaufort, Robeson, Wilson, and Johnston counties, NC had symptoms consistent with target spot. Symptoms consisted of roughly circular, necrotic leaf lesions from minute to 11 mm in diameter, though typically approximately 4 to 5 mm in diameter, and with a yellow margin. Large lesions occasionally exhibited a zonate pattern often associated with this disease. Microscopic examination of the lesions revealed the presence of spores (conidia) typical of C. cassiicola (1). Conidia were mostly three to five septate with a central hilum at the base and ranged in size from 7 to 22 wide × 39 to 520 μm long. Three commercial soybean fields near Blackville, SC (Barnwell County) were severely affected by this disease and it caused premature defoliation. Nineteen of twenty-seven maturity group VII and VIII genotypes in the 2004 Clemson University soybean variety trial near Blackville, SC had visible symptoms of target spot. Heavy rainfall associated with hurricanes during September 2004 probably enhanced the incidence of this disease, and yield suppression due to target spot was estimated at 20 to 40% in some fields. In 2005, 20 of 161 soybean samples submitted to the NCPDIC or collected in surveys from 16 counties were positive for target spot on the basis of microscopic examination. Target spot also was diagnosed in six counties (Baldwin, DeKalb, Elmore, Fayette, Macon, and Pickens) in Alabama and in four additional counties (Bamberg, Hampton, Orange-burg, and Calhoun) in South Carolina in 2005. Records from the NCPDIC indicate that target spot had not been diagnosed on soybean in North Carolina since 1981. The large increase in incidence of target spot in the southeast may be related to changes in weather patterns, changes in pathogen virulence, and/or the introduction of more susceptible host genotypes. }, number={7}, journal={PLANT DISEASE}, author={Koenning, SR and Creswell, TC and Dunphy, EJ and Sikora, EJ and Mueller, JD}, year={2006}, month={Jul}, pages={974–974} }
 @article{jordan_bailey_barnes_bogle_bullen_brown_edmisten_dunphy_johnson_2002, title={Yield and economic return of ten peanut-based cropping systems}, volume={94}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2002.1289}, abstractNote={Research was conducted in North Carolina at two locations from 1997 through 2000 to determine net returns of 10 cropping systems during a 4‐yr cropping cycle that included peanut (Arachis hypogaea L.), cotton (Gossypium hirsutum L.), soybean [Glycine max (L.) Merr.], and corn (Zea mays L.). Cylindrocladium black rot [caused by Cylindrocladium parasiticum] (CBR) increased when soybean was included in the rotation sequence or when peanut was grown continuously. The CBR‐resistant cultivar NC 12C increased yield compared with the susceptible cultivar NC 7 when this disease was present. Cotton was a better rotation crop than corn at one of two locations with respect to peanut yield and gross economic value in the final year of the study. Net returns were substantially lower when peanut was marketed for export in the current federal program rather than at the quota price. However, the profitability ranking among cropping systems changed little regardless of marketing system. Crop yield and net return were influenced by crop selection, weather conditions, and commodity prices during the 4 yr.}, number={6}, journal={AGRONOMY JOURNAL}, author={Jordan, DL and Bailey, JE and Barnes, JS and Bogle, CR and Bullen, SG and Brown, AB and Edmisten, KL and Dunphy, EJ and Johnson, PD}, year={2002}, pages={1289–1294} }