Monday, December 11, 2006
D0091

Variation in degree-day requirements for alfalfa weevil, Hypera postica (Gyllenhal), larval development by location in Eastern Nebraska

Abby R. Stilwell, abbyrose@inebraska.com1, Robert J. Wright, rwright2@unl.edu1, Thomas E. Hunt, THUNT2@unl.edu1, and Erin Blankenship, eblankenship2@unl.edu2. (1) University of Nebraska - Lincoln, Entomology, 202 Plant Industry Bldg, Lincoln, NE, (2) University of Nebraska - Lincoln, Statistics, 340 Hardin Hall, P.O. Box 830963, Lincoln, NE

A two year study was conducted from 2005 to 2006 in eastern Nebraska to determine the variation in degree-day requirements for larval development of the alfalfa weevil, Hypera postica (Gyllenhal), in three locations along a latitudinal gradient. Three alfalfa fields, close in distance to each other, were selected in each location (north, central and south) of eastern Nebraska. Sampling for alfalfa weevil larvae began in the spring when larvae were first detected, and continued until larvae were no longer detected. The shake-bucket method was used to sample for larvae and samples were removed to the laboratory to be counted and measured to determine age class. Daily temperature maximums and minimums were collected from the nearest weather station to each of the three locations. Temperature data was used to determine degree-day accumulations for alfalfa weevils in each location and degree-days were compared to determine variation along a latitudinal gradient.


Species 1: Coleoptera Curculionidae Hypera postica (alfalfa weevil)