Title page for ETD etd-05022009-040359
|Type of Document
||Laub, Curtis A.
||Influence of cover crop management on Armyworm, Pseudaletia Unipuncta (Haworth) seasonal abundance, natural enemies, and yield in no-till corn, and diurnal abundance and spatial distribution of Armyworm
||Master of Science
|No Advisors Found
|Date of Defense
Rye (Secale cereale L.) used as a winter cover crop was killed by paraquat
or by mowing with a bushog. In subsequent no-till corn, early season armyworm,
Pseudaletia unipuncta (Lepidoptera: Noctuidae) abundance was lower in the
mowed treatment compared with the sprayed treatment. Total cumulative
armyworm-days in the sprayed treatment were greater than in the mowed
treatment and were significantly greater in the sprayed treatment in two fields.
Lower armyworm populations may have resulted from a combination of mowing
which physically destroyed some larvae, and predation by generalist predators
attracted to the moist conditions provided by the mulch of mowed rye. Twelve
species of parasitoids attacked armyworm. Glyptapanteles 111ilitaris (Walsh)
(Hymenoptera: Braconidae) and Periscepsia laevigata (Wulp) (Diptera:
Tachinidae) were the most abundant parasitoids. Seasonal parasitization rates
ranged from 36-45%. Parasitism did not differ significantly between treatments.
Mowing the cover crop was 40% less expensive than spraying. Corn silage yields
did not differ significantly between treatments, but the average increase in net
benefit from mowing compared to spraying was $91-113/ha.
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