@article{nalyanya_gore_linker_schal_2009, title={German Cockroach Allergen Levels in North Carolina Schools: Comparison of Integrated Pest Management and Conventional Cockroach Control}, volume={46}, ISSN={["1938-2928"]}, DOI={10.1603/033.046.0302}, abstractNote={Cockroach suppression is fundamental to cockroach allergen mitigation in infested homes. The effects of various cockroach control strategies on cockroach populations and allergen concentration have not been examined in schools. This study was conducted to compare the effectiveness of integrated pest management (IPM) and conventional pest control in controlling German cockroach (Blattella germanica L.) infestations and concentrations of the cockroach allergen Bla g 1 in public school buildings. Two school districts included six schools that used conventional pest control and one district included seven schools that used IPM to control pests. Cockroach traps were deployed to assess the level of infestation, settled dust samples were collected in food service areas, classrooms, and other school areas, and the Bla g 1 allergen was quantified by ELISA. Both cockroach counts and Bla g 1 concentrations were dependent on the pest control approach, with highly significant differences between IPM-treated schools and conventionally treated schools in both the cockroach mean trap counts (0 versus 82.6 +/- 17.3 cockroaches/trap/wk, respectively) and in the amount of Bla g 1 in dust samples (2.8 +/- 0.3 versus 30.6 +/- 3.4 U/g dust). Cockroaches and Bla g 1 were primarily associated with food preparation and food service areas and much less with classrooms and offices. Our data extend recent findings from studies in homes, showing that cockroach allergens can be reduced by cockroach elimination alone or by integrating several tactics including education, cleaning, and pest control. IPM is not only effective at controlling cockroaches but also can lead to long-term reductions in cockroach allergen concentrations, resulting in a healthier environment for students and school personnel.}, number={3}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, author={Nalyanya, Godfrey and Gore, J. Chad and Linker, H. Michael and Schal, Coby}, year={2009}, month={May}, pages={420–427} }
 @article{witting-bissinger_orr_linker_2008, title={Effects of floral resources on fitness of the parasitoids Trichogramma exiguum (Hymenoptera: Trichogrammatidae) and Cotesia congregata (Hymenoptera: Braconidae)}, volume={47}, ISSN={["1090-2112"]}, DOI={10.1016/j.biocontrol.2008.07.013}, abstractNote={This study was conducted to determine if floral resources enhanced longevity and fecundity of the egg parasitoid Trichogramma exiguum Pinto & Platner and longevity of the larval parasitoid Cotesia congregata (Say). Newly eclosed (⩽12 h) female wasps were provisioned with fennel (Foeniculum vulgare P. Mill.) or buckwheat (Fagopyrum esculentum Moench) flowers or one of two controls: honey or water. Wasps were monitored daily until all had died. Daily egg production by T. exiguum was monitored using Ephestia kuehniella Keller egg cards. Longevity of both T. exiguum (6.7 d) and C. congregata (5.1 d) provided buckwheat flowers was increased approximately 8.5-fold compared with wasps provided only water. Buckwheat-provisioned T. exiguum exhibited 2-fold greater longevity than those provided fennel. Longevity of C. congregata provisioned with fennel and honey was not statistically different. Water-provisioned T. exiguum and C. congregata exhibited the shortest longevity (0.8 and 0.6 d, respectively). Total fecundity was 6.3-fold greater in T. exiguum provisioned with buckwheat and 2.3-fold greater in T. exiguum provisioned with fennel than in water controls. Average female to male ratio of progeny over the lifetime of each female was significantly greatest in T. exiguum provisioned with water alone, likely because of sperm depletion in wasps exhibiting greater longevity. Total mean number of female offspring produced was significantly greatest in T. exiguum provided honey or buckwheat flowers although no difference in total female offspring were observed between adults provisioned with buckwheat or fennel flowers. Our results show that provisioning T. exiguum with honey and buckwheat flowers resulted in greater longevity, total fecundity, and lifetime production of female offspring than water alone. Buckwheat flowers also lead to greater longevity in C. congregata.}, number={2}, journal={BIOLOGICAL CONTROL}, author={Witting-Bissinger, B. E. and Orr, D. B. and Linker, H. M.}, year={2008}, month={Nov}, pages={180–186} }
 @article{witting_orr_linker_2007, title={Attraction of insect natural enemies to habitat plantings in north carolina}, volume={42}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-42.4.439}, abstractNote={Two studies were conducted to evaluate the relative attractiveness of floral habitats that may provide nectar and pollen food resources to natural enemies of agricultural insect pests in North Carolina. In the first study, timed observations were made of insect flower-feeding to estimate attraction of natural enemies to 16 plant species in 2004 and 5 plant species in 2005. Insects were identified to the family level and assigned to 1 of 6 feeding groups. In both years, crop predators fed from fennel (Foeniculum vulgare P. Mill.) flowers in greater abundance than from any other flowers observed. Crop parasitoids fed most often on fennel in 2005. In both years, the remaining insect feeding groups other than pollinators were not significantly affected by flower species. In 2005 the response of representatives of 3 families of egg parasitoids (Mymaridae, Scelionidae, and Trichogrammatidae) to 6 habitat plants (black-eyed Susan, buckwheat, fennel, cock's comb [Celosia cristata L.], Shasta daisy [Leucanthemum × superbum (J. W. Ingram) Berg, ex Kent.], and yarrow [Achillea millefolium L.]) was determined. Crabgrass (Digitaria spp. Haller), that exhibited no obvious flowering, served as a control. Results demonstrated that flower species and height affected insects of all 3 families of parasitoids, but removal of flowers only affected scelionids which were trapped in greater abundance in cock's comb plots at flower height. Mymarids were most abundant at 0.5 times the flower height in black-eyed Susan plots regardless of flower presence, and trichogrammatids were trapped in greatest abundance at 0.5 times the canopy height in unmowed crabgrass plots. Our results indicate that habitat plantings may attract egg parasitoids, but that flowers themselves do not appear to be responsible for this attraction.}, number={4}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Witting, B. E. and Orr, D. B. and Linker, H. M.}, year={2007}, month={Oct}, pages={439–456} }
 @article{forehand_orr_linker_2006, title={Evaluation of a commercially available beneficial insect habitat for management of Lepidoptera pests}, volume={99}, DOI={10.1093/jee/99.3.641}, abstractNote={A field study was conducted in 2003 and 2004 at the Center for Environmental Farming Systems in Goldsboro, NC, to evaluate the effectiveness of a commercially available beneficial insect habitat in decreasing pest caterpillar populations in organically managed tomato, Lycopersicon esculentum Mill., plots. Six pairs of tomato plots were established and a commercial beneficial insect habitat seed mix (Peaceful Valley’s Good Bug Blend) transplanted around the perimeter of treatment plots, whereas a brown-top millet, Brachiaria ramose (L.) Stapf., border was planted around control plots. Egg predation, egg parasitism by trichogrammatid wasps, and larval parasitism by braconid wasps was monitored throughout the growing season to determine whether habitat increased their activity. In both years of this study, the density of Helicoverpa zea (Boddie) and Manduca spp. eggs was not significantly different between treatment and control plots. Although parasitism was the most important component of egg mortality (19–49%), parasitism was not significantly different between habitat types. Identifiable predation was a minor component (3–9%) of egg fate; it is possible that unidentified predation may be part of the ≈35–52% of eggs that met unknown fates. Larval parasitism levels ranged from ≈10 to 90% but was not significantly influenced by the presence of beneficial insect habitat in either year of the study. These results demonstrate that natural enemy activity in organic tomatoes was not amplified, and pest populations were not reduced by the presence of a commercially available beneficial insect habitat.}, number={3}, journal={Journal of Economic Entomology}, author={Forehand, L. M. and Orr, D. B. and Linker, H. M.}, year={2006}, pages={641–647} }
 @article{forehand_orr_linker_2006, title={Insect communities associated with beneficial insect habitat plants in North Carolina}, volume={35}, ISSN={["1938-2936"]}, DOI={10.1603/0046-225X(2006)35[1541:ICAWBI]2.0.CO;2}, abstractNote={This study recorded the arthropod communities present in three commercially available beneficial insect habitat seed mixes (Peaceful Valley’s Good Bug Blend, Clyde Robin’s Border Patrol, and Heirloom Seed’s Beneficial Insect Mix) and three commonly grown cut flower/herb plantings (Zinnia, Celosia, and fennel). Communities were sampled three ways: (1) foliar and floral collections were made using a D-Vac and aerial nets, and insects were identified to family and assigned to feeding groups; (2) pitfall traps were used to collect ground beetle and ground-dwelling spider populations; and (3) evening observations recorded visits by noctuid (Lepidoptera: Noctuidae) and hawk moths (Lepidoptera: Sphingidae) to flowers. Overall, Good Bug Blend had the highest abundance and diversity of beneficial parasitoids, predators, and ground beetles. However, along with Border Patrol, it also harbored the highest diversity and abundance of crop-feeding herbivores. The Border Patrol plantings had the highest diversity and abundance of insect herbivore crop pests and the highest number of feeding visits by pest moth species during evening observations. The moth visits were most likely caused by the presence of evening primrose in this mix that blooms at dusk when moths are most active. Celosia harbored the greatest diversity and abundance of predators and parasitoids in the cut flower/herb plots. Fennel had the lowest overall abundance and diversity of all the plantings, but this may have been caused by late summer flowering.}, number={6}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Forehand, L. M. and Orr, D. B. and Linker, H. M.}, year={2006}, month={Dec}, pages={1541–1549} }
 @article{schroeder_creamer_linker_mueller_rzewnicki_2006, title={Interdisciplinary and multilevel approach to organic and sustainable agriculture education at North Carolina State University}, volume={16}, number={3}, journal={HortTechnology}, author={Schroeder, M. S. and Creamer, N. G. and Linker, H. M. and Mueller, J. P. and Rzewnicki, P.}, year={2006}, pages={418–426} }
 @article{williams_linker_waldvogel_leidy_schal_2005, title={Comparison of conventional and integrated pest management programs in public schools}, volume={98}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-98.4.1275}, abstractNote={This study compared an integrated pest management (IPM) program with conventional, calendar-based pest control in nine North Carolina elementary schools. Both programs primarily targeted the German cockroach, Blattella germanica (L.). The IPM program relied heavily on monitoring and baiting, whereas the conventional approach used baseboard and crack-and-crevice sprays of insecticides. Within the constraints of an existing pest management contract, we quantified service duration, materials used, cost, levels of cockroach infestation, and the pesticide residues generated by the two service types. IPM services were significantly more time-consuming than conventional services, resulting in a significantly higher cost associated with labor. Nevertheless, the two types of treatments incurred similar total costs, and the efficacy of both treatments was also similar. Most importantly, pest monitoring, a central element of the IPM program, revealed few cockroaches and indicated that most of the conventional treatments were unnecessary. Environmental residues of the organophosphate pesticides acephate, chlorpyrifos, and propetamphos were significantly higher in swab samples taken in the conventionally treated schools. This study demonstrates that an IPM program is an appropriate and preferable alternative to conventional methods of pest control in the school environment.}, number={4}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Williams, GM and Linker, HM and Waldvogel, MG and Leidy, RB and Schal, C}, year={2005}, month={Aug}, pages={1275–1283} }
 @article{nalyanya_lilley_linker_waldvogel_2005, title={Practices and perceptions of school integrated pest management by North Carolina pest-management professionals}, volume={22}, number={3-4}, journal={Journal of Agricultural and Urban Entomology}, author={Nalyanya, G. W. and Lilley, S. C. and Linker, H. M. and Waldvogel, M. G.}, year={2005}, pages={203–215} }
 @article{schmidt_linker_orr_kennedy_2003, title={Variation in biological parameters of Trichogramma spp. purchased from commercial suppliers in the United States}, volume={48}, ISSN={["1386-6141"]}, DOI={10.1023/A:1025751428043}, number={5}, journal={BIOCONTROL}, author={Schmidt, VB and Linker, HM and Orr, DB and Kennedy, GG}, year={2003}, month={Oct}, pages={487–502} }
 @article{mueller_barbercheck_bell_brownie_creamer_hitt_hu_king_linker_louws_et al._2002, title={Development and implementation of a long-term agricultural systems study: Challenges and opportunities}, volume={12}, number={3}, journal={HortTechnology}, author={Mueller, J. P. and Barbercheck, M. E. and Bell, M. and Brownie, C. and Creamer, N. G. and Hitt, A. and Hu, S. and King, L. and Linker, H. M. and Louws, F. J. and et al.}, year={2002}, pages={362–368} }
 @article{weber_wilkerson_linker_wilcut_leidy_senseman_witt_barrett_vencill_shaw_et al._2000, title={A proposal to standardize soil/solution herbicide distribution coefficients}, volume={48}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2000)048[0075:APTSSS]2.0.CO;2}, abstractNote={Herbicide soil/solution distribution coefficients (Kd) are used in mathematical models to predict the movement of herbicides in soil and groundwater. Herbicides bind to various soil constituents to differing degrees. The universal soil colloid that binds most herbicides is organic matter (OM), however clay minerals (CM) and metallic hydrous oxides are more retentive for cationic, phosphoric, and arsenic acid compounds. Weakly basic herbicides bind to both organic and inorganic soil colloids. The soil organic carbon (OC) affinity coefficient (Koc) has become a common parameter for comparing herbicide binding in soil; however, because OM and OC determinations vary greatly between methods and laboratories, Koc values may vary greatly. This proposal discusses this issue and offers suggestions for obtaining the most accurate Kd, Freundlich constant (Kf), and Koc values for herbicides listed in the WSSA Herbicide Handbook and Supplement.}, number={1}, journal={WEED SCIENCE}, author={Weber, JB and Wilkerson, GG and Linker, HM and Wilcut, JW and Leidy, RB and Senseman, S and Witt, WW and Barrett, M and Vencill, WK and Shaw, DR and et al.}, year={2000}, pages={75–88} }
 @article{pierce_warren_mikkelsen_linker_1999, title={Effects of soil calcium and pH on seed germination and subsequent growth of large crabgrass (Digitaria sanguinalis)}, volume={13}, ISSN={["0890-037X"]}, DOI={10.1017/s0890037x00041968}, abstractNote={Large crabgrass is a problem weed in horticultural crops, particularly in turfgrass in the southeastern United States. If growth of large crabgrass could be suppressed via soil pH or calcium levels, control of this weed in turfgrass might be improved while minimizing herbicide usage. To determine the effect of soil calcium and pH on germination and growth of large crabgrass, seeds were sown in a loamy sand soil amended with calcium carbonate (CaCO 3 ) or magnesium carbonate (MgCO 3 ) that established a range of soil pH from 4.8 to 7.8. Seeds were also sown in soil amended similarly with calcium sulfate (CaSO 4 ), which does not affect pH, that established a range of exchangeable Ca levels corresponding to the Ca range in CaCO 3 from pH 4.8 to 7.8. Seed germination of large crabgrass was unaffected by pH when soil was amended with CaCO 3 , whereas seed germination decreased with increasing pH when soil was amended with MgCO 3 . Crabgrass germination was not affected by Ca (CaSO 4 ) independent of pH changes. Increasing soil pH reduced shoot and root dry weights of seedlings regardless of material used to raise pH. Maximum shoot dry weights occurred at pH 4.8 in the unamended soil, whereas maximum root dry weights occurred at ranges from pH 5.8 to 6.3 for CaCO 3 and pH 5.3 to 5.8 for MgCO 3 . Shoot and root dry weights were not affected by Ca when soil was amended with CaSO 4 . By raising soil pH levels, the growth of large crabgrass and its ability to compete with turfgrass may be reduced. Raising exchangeable Ca does not appear to be an effective management tool for control of this weed species.}, number={2}, journal={WEED TECHNOLOGY}, author={Pierce, GL and Warren, SL and Mikkelsen, RL and Linker, HM}, year={1999}, pages={421–424} }
 @article{zasada_linker_coble_1997, title={Initial weed densities affect no-tillage weed management with a rye (Secale cereale) cover crop}, volume={11}, ISSN={["0890-037X"]}, DOI={10.1017/s0890037x00045279}, abstractNote={The objective of this research was to evaluate the influence of different initial weed densities on weed control effectiveness in no-tillage corn at two locations in North Carolina during 1994 and 1995. Different weed densities were established over a 4-year period (1989–1992) by using various weed management strategies. Resultant density levels were estimated and used to establish high and low weed density plots. Treatments applied were PRE, POST, at-planting, and an untreated control. Weed density estimates were made 37 and 57 DAP. Common lambsquarters at low densities (20 to 40 weeds/m 2 ) was controlled with the cover crop alone, but common lambsquarters at high densities (150 to 170 weeds/m 2 ) and redroot pigweed at any density were not controlled. POST herbicides reduced weed densities as well as the PRE herbicides, regardless of initial weed densities.}, number={3}, journal={WEED TECHNOLOGY}, author={Zasada, IA and Linker, HM and Coble, HD}, year={1997}, pages={473–477} }