Document Type

Thesis - Open Access

Award Date

1982

Degree Name

Master of Science (MS)

Department / School

Entomology-Zoology

First Advisor

David D. Walgenbach

Abstract

The European corn borer (Lepidoptera: Pyralidae) varies as an

economically significant pest in South Dakota from south to north. In

the northern part of the state the European corn borer (ECB) is limited

to one generation per year. In contrast, there are localized sites

along the Missouri River in southern South Dakota which usually

experience a substantial second brood population. Infestation by

either first or second brood ECB occurs at different stages in the

developmental sequence of the corn plant. As such, each brood must be

considered separately when assessing relationships between yield loss

and ECB larval cavities within the plant. Berry and Campbell (1978)

reported that plants .infested by both first and second generation ECB

incurred greater yield reductions than did plants infested by only the

first brood. On a yield loss per cavity basis, the first brood had a

greater impact on yield than did the second. Contrary to this, Lynch

(1980) observed a loss of 4.2 Bu/A/cavity with plants infested during

the pollen shedding stage of development, compared to a 3.4 Bu/A/cavity

loss for plants infested during the whorl stage. Under equal infestation

levels Jarvis et al. (1961) found the first brood to cause more

damage than the second. Further investigation by Lynch et al. (1980)

revealed greater yield losses due to infestation during the pollen

shedding stage (second brood). Differences in varieties and larval

survival may partially explain these contradictory results. Jarvis et al. (1961) observed no synergistic relationship between

first and second brood induced yield reductions when plants were infested by both generations. In Prince Edward Island, Canada,Thompson and White (1977) showed differences in grain yield but no

significant difference in silage yield between insecticide treated and

control plots. The impact of first or second brood ECB at any location

is dependent on the relative population levels present. Kwolek and

Brindley (1959) illustrated this point by reporting on the inconsistency

from state to state with regard to the different impact of the

two broods. In Ohio the second brood was found to be the most influential

with only a small first brood population present. First brood had

a greater impact on yield in Minnesota while Iowa corn was subject to

approximately equal infestation by both generations. Chiang et al. (1960) noted that the ECB females prefer to oviposit

on the most vigorous plants in the area. First brood females

prefer the earlier planted, taller corn, while the second brood females

actively select the later planted more succulent plants that are

shedding pollen. The production and use of irrigated long season corn

hybrids, early planting and heavy fertilization requires monitoring for

both first and second generation ECB.

Artificial infestation studies have elucidated the relationships

between generation of attack, cavity counts and yield. To

date, however, no quantitative studies have been conducted to ascertain these relationships with naturally occurring populations of the ECB in South Dakota. The objective of this study was to assess the impact of first and second generation ECB on total plant weight and grain yield. Studies were conducted at three locations in South Dakota. Analyses were made on either grain yield or total plant weight (cut 4" aboveground) recorded both at the time of harvest and on a dry matter basis.

Library of Congress Subject Headings

European corn borer
Corn -- Diseases and pests -- South Dakota

Description

Includes bibliographical references (pages 43-46)

Format

application/pdf

Number of Pages

51

Publisher

South Dakota State University

Rights

No Copyright - Non-Commercial Use Only
http://rightsstatements.org/vocab/NoC-NC/1.0/

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