Type of Document Master's Thesis Author Kuhar, Patrick Thomas URN etd-11072008-063517 Title Western corn rootworm damage assessment in Virginia and adult sampling with commercial yellow sticky traps Degree Master of Science Department Entomology Advisory Committee
Advisor Name Title Youngman, Roger R. Committee Chair Pfeiffer, Douglas G. Committee Member Pienkowski, Robert L. Committee Member Keywords
- insect infestation
Date of Defense 1996-05-13 Availability restricted Abstract
The risk of corn rootworm damage to continuously-grown corn was assessed in 32 fields from seven counties in Virginia in 1993 and 1994, Approximately 28% of the fields examined had economic root damage in corn left untreated with a soil insecticide. In addition, 190/0 of the fields overall had an economic loss in silage due to corn rootworm damage.
A second study evaluated the effectiveness of using adult corn rootworm counts on commercial Olson yellow sticky traps and ear-zone regions of corn plants to predict subsequent damage to corn. Regression models for each sampling method were used to calculate economic thresholds of 20 adults per trap per wk for the Olson trap and 0.3 adults per stalk for the ear-zone visual count method. Adult counts on Olson traps obtained in mid-Aug correctly predicted economic damage to com 81 % of the time, and resulted in only one serious error of failing to predict economic damage to corn. A sampling plan for the use of Olson traps is suggested.
A third study investigated a possible sexual dimorphism in the elytra coloration pattern of western corn rootworm, and compared the sex ratio of adults captured yellow sticky traps with those obtained by aspiration. Striped and solid variations in elytra pattern were found in both sexes of western corn rootworm; however, 98% of the adults that exhibited the solid elytra pattern were male. The sex ratio of adults varied over time; however, in all cases, sticky traps captured a significantly greater proportion of males compared with aspiration.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access LD5655.V855_1996.K843.pdf 3.85 Mb 00:17:49 00:09:09 00:08:01 00:04:00 00:00:20next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
If you have questions or technical problems, please Contact DLA.