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

Rye (<i>Secale cereale</i> 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, <i>Pseudaletia unipuncta</i> (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. <i>Glyptapanteles 111ilitaris</i> (Walsh) (Hymenoptera: Braconidae) and <i>Periscepsia laevigata</i> (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.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Entomology

Department dc:contributor.department

Entomology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1990

Author dc:creator

• Laub, Curtis A.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-05022009-040359

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42389