@article{smith_garrison_hollowell_isleib_shew_2008, title={Evaluation of application timing and efficacy of the fungicides fluazinam. and boscalid for control of Sclerotinia blight of peanut}, volume={27}, ISSN={["0261-2194"]}, DOI={10.1016/j.cropro.2007.11.010}, abstractNote={Sclerotinia blight of peanut (Arachis hypogaea) is caused by the soilborne fungus Sclerotinia minor. Management of Sclerotinia blight of peanut requires an integrated approach that includes rotation with non-hosts, resistant cultivars, cultural practices, and fungicides. Greenhouse experiments compared fluazinam and boscalid and investigated pre- and post-inoculation applications of fungicide or no fungicide to control infections by S. minor. Significant reductions in successful infections in the greenhouse occurred when fungicide was applied prior to, or up to 2 d after, inoculation, but not when applied 4 d after inoculation. Field experiments were conducted from 2004 to 2006 to investigate the comparative efficacy of the fungicides fluazinam and boscalid using alternating sequences of those fungicides or no fungicide for each of three sprays per season. In the field, applications of fungicide that preceded the largest incremental increase in disease incidence provided the best control of disease or increased yield. In both the field and greenhouse studies boscalid performed marginally better than fluazinam. Disease advisories or intensive scouting should be used to determine when epidemics initiate so that a fungicide can be applied prior to infection.}, number={3-5}, journal={CROP PROTECTION}, author={Smith, D. L. and Garrison, M. C. and Hollowell, J. E. and Isleib, T. G. and Shew, B. B.}, year={2008}, pages={823–833} }
 @article{smith_hollowell_isleib_shew_2007, title={A site-specific, weather-based disease regression model for Sclerotinia blight of peanut}, volume={91}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-91-11-1436}, abstractNote={ In North Carolina, losses due to Sclerotinia blight of peanut, caused by the fungus Sclerotinia minor, are an estimated 1 to 4 million dollars annually. In general, peanut (Arachis hypogaea) is very susceptible to Sclerotinia blight, but some partially resistant virginia-type cultivars are available. Up to three fungicide applications per season are necessary to maintain a healthy crop in years highly favorable for disease development. Improved prediction of epidemic initiation and identification of periods when fungicides are not required would increase fungicide efficiency and reduce production costs on resistant and susceptible cultivars. A Sclerotinia blight disease model was developed using regression strategies in an effort to describe the relationships between modeled environmental variables and disease increase. Changes in incremental disease incidence (% of newly infected plants of the total plant population per plot) for the 2002–2005 growing seasons were statistically transformed and described using 5-day moving averages of modeled site-specific weather variables (localized, mathematical estimations of weather data derived at a remote location) obtained from SkyBit (ZedX, Inc.). Variables in the regression to describe the Sclerotinia blight disease index included: mean relative humidity (linear and quadratic), mean soil temperature (quadratic), maximum air temperature (linear and quadratic), maximum relative humidity (linear and quadratic), minimum air temperature (linear and quadratic), minimum relative humidity (linear and quadratic), and minimum soil temperature (linear and quadratic). The model explained approximately 50% of the variability in Sclerotinia blight index over 4 years of field research in eight environments. The relationships between weather variables and Sclerotinia blight index were independent of host partial resistance. Linear regression models were used to describe progress of Sclerotinia blight on cultivars and breeding lines with varying levels of partial resistance. Resistance affected the rate of disease progress, but not disease onset. The results of this study will be used to develop site- and cultivar-specific spray advisories for Sclerotinia blight. }, number={11}, journal={PLANT DISEASE}, author={Smith, D. L. and Hollowell, J. E. and Isleib, T. G. and Shew, B. B.}, year={2007}, month={Nov}, pages={1436–1444} }
 @article{smith_hollowell_isleib_shew_2006, title={Analysis of factors that influence the epidemiology of Sclerotinia minor on peanut}, volume={90}, ISSN={["1943-7692"]}, DOI={10.1094/PD-90-1425}, abstractNote={ In North Carolina, sclerotia of Sclerotinia minor germinate myceliogenically to initiate infections on peanut. The effects of soil temperature and soil matric potential (ψM on germination and growth of S. minor have not been well characterized, and little is known about relative physiological resistance in different parts of the peanut plant. Laboratory tests examined the ability of the fungus to germinate, grow, and infect detached peanut leaflets at soil temperatures ranging from 18 to 30°C at ψM of -100, -10, and -7.2 kPa. In addition, detached pegs, leaves, main stems, and lateral branches from three peanut lines varying in field resistance were examined for resistance to infection by S. minor. Sclerotial germination was greatest at 30°C and ψM of -7.2 kPa. Final mycelial diameters decreased with decreasing ψM, whereas soil matric potential did not affect lesion development. Mycelial growth and leaflet lesion expansion were maximal at 18 or 22°C. Soil ψM did not affect leaflet infection and lesion expansion. Lesions were not observed on leaves incubated at temperatures of 29°C or above, but developed when temperatures were reduced to 18 or 22°C 2 days after inoculation. Pegs and leaflets were equally susceptible to infection and were more susceptible than either main stems or lateral branches. Results of this work, particularly the effects of temperature on S. minor, and knowledge of peanut part susceptibility has application in improving Sclerotinia blight prediction models for recommending protective fungicide applications. }, number={11}, journal={PLANT DISEASE}, author={Smith, D. L. and Hollowell, J. E. and Isleib, T. G. and Shew, B. B.}, year={2006}, month={Nov}, pages={1425–1432} }
 @article{isleib_rice_mozingo_copeland_graeber_shew_smith_melouk_stalker_2006, title={Registration of N96076L peanut germplasm line}, volume={46}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2005.12.0479}, abstractNote={N96076L (Reg. no. GP-125, PI 641950) is a large-seeded virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) germplasm line with resistance to multiple diseases including early leafspot (caused by Cercospora arachidicola S. Hori), Cylindrocladium black rot (CBR) {caused by Cylindrocladium parasiticum Crous, Wingfield & Alfenas [syn. C. crotalariae (Loos)D.K.Bell&Sobers]}, Sclerotiniablight (caused by Sclerotinia minor Jagger), and tomato spotted wilt caused by Tomato spotted wilt virus (TSWV). N96076Lwas released by the NorthCarolinaAgriculturalResearchService (NCARS) in 2005. N96076Lwas tested by theNCARS, by the VirginiaAgricultural Experiment Station (VAES), and the USDA-ARSWheat, Peanut and Other Field Crops Research Unit at Stillwater, OK. N96076L is a virginia market-type line possessing alternate branching pattern, runner growth habit, medium green foliage, large seeds with dull tan testa averaging 880 mg seed, approximately 70% jumbo pods and 22% fancy pods. N96076L is an F4–derived line selected from cross X91053 made in 1991 using NCSU breeding line N90004 as the female and leafspotresistant germplasm line GP NCWS 13 (Stalker et al., 2002) as the male. N90004 was an F5–derived line selected from NCSU cross X84002 between ‘NC 7’ (Wynne et al., 1979) and ‘Florigiant’ (Carver, 1969). GP NC WS 13 has complex ancestry. One quarter of its ancestry comes from GP NC WS 4 (Stalker and Beute, 1993), a tetraploid (2n 5 4x 5 40) selection from a cross between PI 261942 (A. hypogaea subsp. fastigiataWaldron var. fastigiata) and leafspot-resistant diploid (2n5 2x5 20) wild species A. cardenasii Krapov. & W.C. Gregory GKP 10017 (PI 262141). One quarter of GP NC WS 13’s ancestry comes from leafspot-resistantA. hypogaea PI 270807, and one half from the cultivar ‘NC 5’ (Emery andGregory, 1970), which has moderate resistance to early leafspot. F1 plants of cross X91053 were grown at a winter nursery in Puerto Rico, single-seed descent was practiced in the F2 and F3 generations, and single-plant selections were made in the F4 generation. F4:5 families were planted at Peanut Belt Research Station (PBRS) at Lewiston in Bertie County, NC, in a field receiving no fungicide treatment to control leafspot in the summer of 1995. Families exhibiting reduced levels of defoliation were harvested in bulk and retained for evaluation in the Leafspot Test, a two-rep test of defoliation, yield, and grade grown without leafspot control at PBRS in 1996. Family X91053 F2-S-S-08: F05 was numbered N96076L when entered in the 1996 Leafspot Test. Although N96076L was developed for resistance to early leafspot, it also was evaluated for resistance to other diseases common to theVirginia–Carolina region.N96076L’s reaction to early leafspot was evaluated from 1996 through 2004 in 12 field trials with no application of leafspot fungicide during the entire season. Defoliation was rated on a proportional scale of 1 (no defoliation) to 9 (complete defoliation) in late September or early October each year, and yield was measured on the unsprayed plots. Although N96076L had more defoliation than resistant checkGP-NC343(Campbell etal., 1971) (5.5vs.4.3,P, 0.01), it had less than either ‘NC 12C’ (Isleib et al., 1997) (5.7 vs. 6.2 defoliation score,P, 0.01) or ‘Perry’ (Isleib et al., 2003) (5.8 vs. 6.6defoliation score,P,0.01), the twomost resistantvirginiatype cultivars. N96076L did not differ significantly from any of these three checks for yield in the absence of leafspot control. N96076L’s reactions to Cylindrocladium black rot (CBR) and to Sclerotinia blight were evaluated by the NCSU breeding project from 1997 through 2004 in eight replicated tests conducted in North Carolina on naturally infested soils with no chemical control of these diseases. N96076L was not significantly different from the resistant cultivar Perry in incidence of CBR (8 vs. 10%, ns), but it did have lower CBR incidence than NC 12C (9 vs. 21%, P , 0.01) and ‘Gregory’ (Isleib et al., 1999) (8 vs. 17%, P, 0.01). N96076L was not different from the partially resistant cultivar Perry in incidence of Sclerotinia blight (7 vs. 21%, ns), but it did have lower incidence than NC 12C (6 vs. 28%, P , 0.01) and Gregory (7 vs. 30%, P, 0.01). Yield, grade and Sclerotinia blight incidence in N96076L were evaluated by USDA-ARS personnel at Stillwater, OK, in a two-rep trial conducted in infested soil at Fort Cobb, OK, during 1998. Disease incidence in N96076L was less than in any of the lines tested except ‘Tamrun 98’ (Simpson et al., 2000) (16 vs. 30%, ns), but there was no variation in yield among the lines tested. Physiological resistance to S. minor was documented in detached plant part inoculations under controlled laboratory conditions (Smith, 2004, p. 72–93). Lesion development measured by the area under the disease progress curve (AUDPC) was significantly smaller for all parts with the exception of mainstems when compared to NC 12C and NC 7 (P , 0.0001). In the field, resistance most likely due to avoidance was also documented. Fewer infections were detected on lateral branches of N96076L plants when compared with NC 12C (13 vs. 46%, P , 0.01), Perry, (13 vs. 44%, P , 0.01), and ‘VA 98R’ (Mozingo et al., 2000) (13 vs. 23%, P , 0.01). N96076L’s reaction to TSWV was evaluated from 1997 through 2004 in 18 field trials with seeds spaced 50 cm apart and no application of insecticides to control thrips (Frankliniella fusca Hinds), the vector of the virus. N96076L had lower incidence of TSWV symptoms than NC 12C (22 vs. 45%,P, 0.01), Gregory (26 vs. 33%,P, 0.01), and Perry (25 vs. 52%,P, 0.01) and was not different from resistant check PI 576636 (21 vs. 16%, ns). N96076L should be considered resistant to all four of these diseases. Agronomic performance of N96076L was evaluated in 13 trials conducted by the NCARS breeding program over 1996 to 2004. Although yield of N96076L was not significantly different from that of NC 12C (3774 vs. 4050 kg ha, ns), Gregory (3703 vs. 3960 kg ha, ns) or Perry (3702 vs. 3709 kg ha, ns), its average pod brightness (42.7 Hunter L score) (Isleib et al., 1997) was less (44.6 for NC 12C, P, 0.01; 44.3 for Gregory, P, 0.01; and 44.4 for Perry, P, 0.01), making N96076L unsuitable for use as a cultivar for the in-shell market. N96076L is adapted to the Virginia-Carolina peanut production area. Seed of N96076L will be maintained by the N.C. Agricultural Research Service, Box 7643, N.C. State University, Raleigh, NC 27695–7643. Foundation seed will be distributed by the N.C. Foundation Seed Producers, Inc., 8220 Riley Hill Rd., Zebulon, NC 27597. The N.C. Agricultural Research Service will provide small (50–100 seed) samples to research organizations for research purposes.}, number={5}, journal={CROP SCIENCE}, author={Isleib, T. G. and Rice, P. W. and Mozingo, R. W., II and Copeland, S. C. and Graeber, J. B. and Shew, B. B. and Smith, D. L. and Melouk, H. A. and Stalker, H. T.}, year={2006}, pages={2329–2330} }