Location: Rangeland and Pasture ResearchTitle: Growing degree-days accumulation and trends in phenological stages of the maize billbug [Sphenophorus maidis (Chittenden)] in eastern gamagrass [Tripsacum dactyloides (L.) L.] Author
|Dhakal, Kundan - Oak Ridge Institute For Science And Education (ORISE)|
Submitted to: Trends in Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2019
Publication Date: 3/11/2019
Citation: Dhakal, K., Springer, T.L. 2019. Growing degree-days accumulation and trends in phenological stages of the maize billbug [Sphenophorus maidis (Chittenden)] in eastern gamagrass [Tripsacum dactyloides (L.) L.]. Trends in Entomology. 14:71-77.
Interpretive Summary: Maize billbug (Sphenophoris maidis) infestation can reduce forage production and stand longevity, causing significant economic losses in eastern gamagrass (Tripsacum dactyloides). Scientists at the USDA-ARS, Southern Plains Range Research Station, Woodward, OK conducted research to understand the life stages of development of the maize billbug in eastern gamagrass. Growing degree days (GDD), a measurement of heat units over time, calculated from daily maximum and minimum temperatures was used to see if it explains maize billbug activity at its various life stages. Larvae, pupae, and adult populations were greater in reproductive shoots compared to vegetative shoots. For all life stages of the pest, sampled populations were observed between 1967–4234 cumulative growing degree days. This corresponds to availability of high-protein diet from plant tissue during that period. Further research is warranted to develop management strategy that fits well with integrated pest management approach.
Technical Abstract: The maize billbug, [Sphenophoris maidis (Chittenden)] feeds on eastern gamagrass Tripsacum dactyloides (L.) L., causing economic damage. We studied incidence of S. maidis in a six-year-old eastern gamagrass establishment and the influence of cumulative growing degree-days (cGDD) on the phenological stages of the pest for two years. Larval, pupal, and adult life stages of the billbug are described and illustrated. Based on growing degree-days, the 99% quantile for larvae, pupae, and adult maize billbugs was estimated between 1967.8–4234.6 cGDD. Very few pupae were recovered from field sampling, which we relate to short pupation period and weekly sampling interval in our study. Findings of this study are helpful to formulate sustainable maize billbug management strategies.