@article{warfield_hwang_benson_2008, title={Phytophthora blight and dieback in North Carolina nurseries during a 2003 survey}, volume={92}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-92-3-0474}, abstractNote={ A survey of 14 nurseries growing hybrid rhododendron, Pieris spp., or Viburnum spp. was conducted as part of the 2003 Sudden Oak Death Pilot National Survey to determine if Phytophthora ramorum, the causal agent of sudden oak death, had been introduced to nurseries in North Carolina. Over 220,000 hybrid rhododendrons, 1,700 plants of Pieris spp., and 2,800 plants of Viburnum spp. were surveyed. Across nurseries, blight and dieback incidence averaged 2.4% for Pieris spp. and 10% for rhododendron. P. ramorum was not recovered by isolation or detected by polymerase chain reaction in the 347 plant samples collected. Three species of Phytophthora were isolated from hybrid rhododendron and Pieris spp., but no Phytophthora isolates were recovered from Viburnum spp. P. citricola and P. cambivora were isolated most frequently (61 and 39 isolates, respectively), while 2 isolates of P. cactorum were recovered. Occasionally, two Phytophthora spp. were found in the same block of rhododendrons within a nursery, but only one species was recovered from an individual plant. Most cultivars of rhododendron surveyed, including ‘English Roseum,’ ‘Nova Zembla,’ and ‘Roseum Elegans,’ had less than 0.5% incidence of Phytophthora blight and dieback, whereas ‘Lee's Dark Purple’ had 3.8% disease incidence across all nurseries surveyed. }, number={3}, journal={PLANT DISEASE}, author={Warfield, C. Y. and Hwang, J. and Benson, D. M.}, year={2008}, month={Mar}, pages={474–481} }
 @article{hwang_benson_2005, title={Identification, mefenoxam sensitivity, and compatibility type of Phytophthora spp. attacking floriculture crops in North Carolina}, volume={89}, ISSN={["1943-7692"]}, DOI={10.1094/PD-89-0185}, abstractNote={ Phytophthora isolates were collected from floriculture crops grown in commercial greenhouses in North Carolina for species identification, compatibility type determination, and mefenoxam sensitivity tests. Isolation from 41 symptomatic plant species at 29 production locations resulted in 483 isolates from eight crops at seven locations. Phytophthora cryptogea (184 isolates) was recovered from dusty miller and gerbera daisy. All isolates of P. cryptogea were insensitive or intermediate in sensitivity to mefenoxam at 1 μg a.i./ml and were A1 compatibility type. P. nicotianae (273 isolates) was isolated from African violet, lavender, pansy, petunia, and vinca. Of these isolates, 21% were insensitive to mefenoxam at either 1 or 100 μg a.i./ml. Isolates of P. nicotianae from five locations were A2 compatibility type, whereas isolates on pansy at one location were A1 compatibility type. English ivy grown at two locations was infected with P. palmivora. All 26 isolates of P. palmivora were sensitive to mefenoxam and were A1 compatibility type. Mating type and mefenoxam sensitivity were uniform among isolates of P. nicotianae and P. palmivora from a given crop at a given location, suggesting that epidemics within a location may have originated from a single source of inoculum. }, number={2}, journal={PLANT DISEASE}, author={Hwang, J and Benson, DM}, year={2005}, month={Feb}, pages={185–190} }
 @article{hwang_benson_2003, title={Expression of induced systemic resistance in poinsettia cuttings against Rhizoctonia stem rot by treatment of stock plants with binucleate Rhizoctonia}, volume={27}, ISSN={["1049-9644"]}, DOI={10.1016/S1049-9644(02)00185-8}, abstractNote={Three cultivars of poinsettia (V14 Glory, Freedom Red, and Angelica White) were evaluated for induction of host resistance to Rhizoctonia stem rot in cuttings acquired from stock plants treated with binucleate Rhizoctonia (BNR) in a Pesta formulation. Resistance to stem rot in cuttings of V14 Glory was induced within 7 days of treatment with BNR while Freedom Red and Angelica White did not express resistance until 10 or more days after application of BNR to stock plants. None of the cultivars expressed resistance to stem rot when cuttings were taken from stock plants that were treated with BNR for only 3 or 5 days before propagation. Population dynamics of BNR on poinsettia root tissue were consistent with the expression of induced resistance. A dramatic increase of root colonization by BNR was observed in all cultivars between day 5 and 7. The integrated use of both BNR and Burkholderia cepacia, previously characterized as a stem rot control agent during poinsettia propagation, was evaluated to test for enhanced resistance against stem rot. No additive effect on stem rot control was observed when cuttings taken from stock plants treated with BNR were propagated in rooting strips treated with B. cepacia compared to cuttings propagated in root strips treated with B. cepacia alone. Our results may be the first to demonstrate induced systemic resistance by BNR fungi during vegetation propagation where the biocontrol agent applied to roots of a stock plant was able to protect cuttings from Rhizoctonia solani during propagation.}, number={1}, journal={BIOLOGICAL CONTROL}, author={Hwang, J and Benson, DM}, year={2003}, month={May}, pages={73–80} }
 @article{hwang_chilton_benson_2002, title={Pyrrolnitrin production by Burkholderia cepacia and biocontrol of Rhizoctonia stem rot of poinsettia}, volume={25}, ISSN={["1049-9644"]}, DOI={10.1016/S1049-9644(02)00044-0}, abstractNote={Pyrrolnitrin production by Burkholderia cepacia strain 5.5B was closely related to suppression of stem rot of poinsettia caused by Rhizoctonia solani. Selected strains RR 13-1 and UV 19-4, which produced significantly less pyrrolnitrin than the parent strain 5.5B, lost the ability to control stem rot completely. Selected strain RR 21-2 produced the same level of pyrrolnitrin as strain 5.5B and was as effective as strain 5.5B in stem rot control. The effect of medium type and initial pH of medium on pyrrolnitrin production by B. cepacia was investigated to improve efficacy of biocontrol. More pyrrolnitrin was accumulated when the initial pH was adjusted to 5.8 than 6.8. With an initial pH of 5.8, strains of B. cepacia produced more pyrrolnitrin in a nutrient broth medium than in a minimum salts medium. Pyrrolnitrin was the major factor in biocontrol of Rhizoctonia stem rot of poinsettia by B. cepacia. Improvement in biocontrol efficacy may be possible by adjusting culture conditions to optimize pyrrolnitrin production.}, number={1}, journal={BIOLOGICAL CONTROL}, author={Hwang, J and Chilton, WS and Benson, DM}, year={2002}, month={Sep}, pages={56–63} }