TY - JOUR
T1 - Population dynamics and interactions between endemic entomopathogenic nematodes and annual bluegrass weevil populations in golf course turfgrass
AU - McGraw, Benjamin A.
AU - Koppenhöfer, Albrecht M.
N1 - Funding Information:
We appreciate the technical assistance of Eugene and Kathleen Fuzy, Erica Jimenez, Mohammed Saleh and Michael Pesa. We would like to thank Daniel Gruner and three anonymous reviewers for comments on an earlier version of the manuscript. This research was supported by grants from the US Golf Association, the Golf Course Superintendents Association of America—Chapter Supported Research Program (supporting chapters: GCSA of New Jersey, Long Island GCSA, Keystone AGCS), and USDA-Northeastern IPM Grant 2007-34103-18418. This is New Jersey Agricultural Experiment Station Publication No. D-08-08187-06-08 supported by state funds and Regional Research Funds.
PY - 2009/1
Y1 - 2009/1
N2 - Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) (EPNs) are generalist obligate pathogens present in the soil of most ecosystems. They have the potential to infect a broad host range, yet the potential for endemic EPNs to regulate soil-dwelling insect populations has received limited attention. We investigated the population dynamics of endemic EPNs to determine their ability to regulate annual bluegrass weevil (Listronotus maculicollis) (Coleoptera: Curculionidae) populations, a major pest of turfgrass in the northeastern United States. Weekly sampling of nematode and L. maculicollis populations was conducted in untreated fairway transects on three golf courses in New Jersey between April and October of 2006 and 2007. Steinernema carpocapsae and Heterorhabditis bacteriophora were found infecting all weevil stages from third instar to teneral adults. Both EPN species exhibited a distinct seasonality, appearing in high densities in the weeks immediately following high densities of first generation weevils in the soil. A positive temporal relationship was observed between densities of EPN-infected weevils and weevil stages between third instar and pupa, but L. maculicollis generational mortality due to EPN infection was highly variable between years and sites, ranging between 0 and 50%. Although infection densities and larval densities were positively correlated, per capita mortality did not increase with increased weevil densities. EPN distribution dynamically cycled between aggregated and uniform throughout the season across fairways. Few significant relationships were found to support the hypothesis that weevil spatial dispersion influences EPN spatial dispersion. The variability in EPN seasonal occurrence and generational impact on L. maculicollis together with the lack of spatial association with L. maculicollis suggest an inability of endemic EPN populations to reliably regulate weevil populations on golf course fairways.
AB - Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) (EPNs) are generalist obligate pathogens present in the soil of most ecosystems. They have the potential to infect a broad host range, yet the potential for endemic EPNs to regulate soil-dwelling insect populations has received limited attention. We investigated the population dynamics of endemic EPNs to determine their ability to regulate annual bluegrass weevil (Listronotus maculicollis) (Coleoptera: Curculionidae) populations, a major pest of turfgrass in the northeastern United States. Weekly sampling of nematode and L. maculicollis populations was conducted in untreated fairway transects on three golf courses in New Jersey between April and October of 2006 and 2007. Steinernema carpocapsae and Heterorhabditis bacteriophora were found infecting all weevil stages from third instar to teneral adults. Both EPN species exhibited a distinct seasonality, appearing in high densities in the weeks immediately following high densities of first generation weevils in the soil. A positive temporal relationship was observed between densities of EPN-infected weevils and weevil stages between third instar and pupa, but L. maculicollis generational mortality due to EPN infection was highly variable between years and sites, ranging between 0 and 50%. Although infection densities and larval densities were positively correlated, per capita mortality did not increase with increased weevil densities. EPN distribution dynamically cycled between aggregated and uniform throughout the season across fairways. Few significant relationships were found to support the hypothesis that weevil spatial dispersion influences EPN spatial dispersion. The variability in EPN seasonal occurrence and generational impact on L. maculicollis together with the lack of spatial association with L. maculicollis suggest an inability of endemic EPN populations to reliably regulate weevil populations on golf course fairways.
UR - https://www.scopus.com/pages/publications/57549118919
UR - https://www.scopus.com/pages/publications/57549118919#tab=citedBy
U2 - 10.1016/j.apsoil.2008.09.002
DO - 10.1016/j.apsoil.2008.09.002
M3 - Article
AN - SCOPUS:57549118919
SN - 0929-1393
VL - 41
SP - 77
EP - 89
JO - Applied Soil Ecology
JF - Applied Soil Ecology
IS - 1
ER -