Masters Theses

Date of Award

8-1988

Degree Type

Thesis

Degree Name

Master of Science

Major

Entomology and Plant Pathology

Major Professor

Charles D. Pless

Committee Members

Reid Gerhardt, Jermome Grant, Robert Miller

Abstract

Selected burley tobacco breeding lines and cultivars were evaluated for colonization by the green peach aphid (CPA), Myzus persicae (Sulzer), in the field and in the laboratory. Tobacco entries utilized in this study included: Five tobacco breeding lines, GR 107, GR 115, GR 131, GR 132 and PDJA 309; three burley tobacco cultivars, 'TN 86' (previously GR 136), 'BU 21' and a standard, 'VA 509'; and a flue-cured tobacco, TI 1112. GR 115, which has non-secreting trichomes, and TN 86, which has secreting trichomes, were further evaluated in the laboratory for lack of colonization by GPA due to predation by convergent lady beetle (CLB), Hippodamia convergens Guerin-Meneville. In the field, without adequate applied or natural control methods, or in the absence of predators, all plants became colonized by the GPA. When CLBs were present, GPA populations were suppressed on the non-secreting breeding lines but not on the secreting breeding lines and cultivars. In the laboratory, under controlled conditions, aphids colonized all entries at similar rates. CLBs did not choose aphid-infested leaves of TN 86; whereas, implied resistance to GPA exhibited by GR 115 was due to CLB selecting aphid-infested leaves of this non-secreting breeding line.

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