Title page for ETD etd-06072004-171156


Type of Document Dissertation
Author Willrich, Melissa Marie
URN etd-06072004-171156
Title Evaluation of Injury and Management Strategies for Stink Bugs (Heteroptera: Pentatomidae) on Cotton, Gossypium Hirsutum L.
Degree Doctor of Philosophy (Ph.D.)
Department Entomology
Advisory Committee
Advisor Name Title
Billy R. Leonard Committee Chair
Guy B. Padgett Committee Member
James L. Griffin Committee Member
Richard N. Story Committee Member
Paul W. Wilson Dean's Representative
Keywords
  • pyrethroids
  • organophosphates
  • boll development
  • no-choice test
  • preference test
  • diplodia
  • fusarium
Date of Defense 2004-06-03
Availability unrestricted
Abstract
The effects of brown stink bug, Euschistus servus (Say), and southern green stink bug, Nezara viridula (L.), feeding on pre-flowering, flowering, and senescing cotton, Gossypium hirsutum L., plants were evaluated in field studies. Vegetative stage seedlings and flower buds (squares) were not significantly injured by adults or nymphs of either species in no-choice studies. Brown stink bug adults induced boll abscission, and reduced seedcotton yield and seed germination in bolls accumulating „T 350, „T 550, and 101 to „T 600 heat units beyond anthesis, respectively. In free-choice tests, boll preference was evaluated during each of the initial five weeks of flowering. Boll density increased from 5.1 to 6.6-fold from week one to week five. There was a corresponding 4.6 to 6.2-fold increase in total bolls injured. Boll injury ranged from 10.7% (week 4) to 27.4% (week 2) and 9.2% (week 3) to 16.0% (week 2) in 2002 and 2003, respectively. The frequency of injured bolls was highest for bolls accumulating 165.2 through 672 heat units beyond anthesis (1.161 to 3.586 cm diameter). However, brown stink bug significantly reduced seedcotton yields during weeks four and five due to the inability of cotton plants to compensate for injured bolls. Infestations of southern green stink bug during boll maturation, in combination with persistent rainfall and humidity, increased the proportion of rotted (2.0-fold) and ˇ§hard lockedˇ¨ (1.4-fold) bolls compared to a non-infested treatment. Although stink bug injury was observed in hard locked (35.8%) and harvestable (20.3%) bolls, other abiotic and/or biotic factors are contributing to late-season harvest losses. In laboratory and field studies, the order of susceptibility (least to most) of stink bug species and life stages to insecticides commonly used for management was adult Euschistus spp. < late-instar nymphs < southern green stink bug adults. These studies defined brown stink bug and southern green stink bug to be significant pests of cotton during boll development stages. Stink bug management strategies should consider species, life stages, and the characteristics of specific insecticides.
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