Group Title: Ecology, economics and behavior of the fall armyworm in field corn /
Title: Ecology, economics and behavior of the fall armyworm in field corn
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 Material Information
Title: Ecology, economics and behavior of the fall armyworm in field corn
Physical Description: x, 60 leaves : ill. ; 28 cm.
Language: English
Creator: Morrill, Wendell L., 1941- ( Dissertant )
Greene, Gerald L. ( Thesis advisor )
Habeck, Dale H. ( Thesis advisor )
Lloyd, James E. ( Reviewer )
Reiskind, Jonathan ( Reviewer )
Walker, Thomas J. ( Reviewer )
Browning, C. B. ( Degree grantor )
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1971
Copyright Date: 1971
Subjects / Keywords: Fall armyworm   ( lcsh )
Entomology and Nematology thesis Ph. D
Corn -- Diseases and pests   ( lcsh )
Dissertations, Academic -- Entomology and Nematology -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Abstract: The fall armyworm, Spodoptera frugiperda (j. E. Smith), overwinters in southern United States and migrates northward during the growing season and attacks many crops. The economic damage level in field com was determined by infesting several com growth stages with known numbers of larvae, measuring larval mortality, weighing ears to determine yields, and comparing yields of infested and uninfested plots. Infestations before tassel and ear emergence did not consistently reduce yields. Infestations, occurring as tassels and ears appeared, showed significant yield reductions in 2 out of 4 plots at a density of 0.8-1.5 worms per plant. Tassel damage was of little importance; ear feeding resulted in some damage. Larvae did not penetrate to the apical bud. In pre-tassel com, most larvae were found in the whorl and furl, while in post- tassel com, larvae were found in the ears. Preference of plant tissues did not appear to be of significant importance in larval distribution on plants, but thigmotaxis may be important. First instar larvae were positively phototactic and negatively geotactic; the responses subsided dixring the second instar. More dispersal per day was found during the first 3 days than the first 12 days of larval life. Movement was greater at higher densities. Newly emerged larvae survived 20-35 hours without feeding. Starvation at this time did not affect pupal weights or duration of the larval stage. During starvation, survival of fifth instar larvae was increased by cannibalism. Sixth instar larvae could survive through pupation without feeding. Larval dimorphism and behavioral differences were shown at high and low densities. Duration of egg development was extended at 4-15 C; mortality increased after 24 hours at 1 C and 72 hours at 4 C. Larval development was extended at 14 C; none survived to pupation at or below this temperature. Pupae survived up to 12 days at G. Pupation occurs in the ground. Development of a cold-resistant stage or selection of a cold-protected pupation site are possible methods of overwintering. Early annual appearance in the North of this pest would pose a serious threat to northern United States agriculture.
Thesis: Thesis (Ph. D.)--University of Florida, 1971.
Bibliography: Bibliography: leaves 56-59.
Additional Physical Form: Also available on World Wide Web
General Note: Typescript.
General Note: Vita.
Statement of Responsibility: by Wendell L. Morrill.
 Record Information
Bibliographic ID: UF00097683
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000318791
oclc - 09177018
notis - ABU5639


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