Title page for ETD etd-04022010-180102


Type of Document Dissertation
Author Koppel, Amanda Leigh
Author's Email Address akoppel@vt.edu
URN etd-04022010-180102
Title Stink bug egg studies in southeastern Virginia: parasitoid survey, and susceptibility and chorion permeability to insecticides
Degree PhD
Department Entomology
Advisory Committee
Advisor Name Title
Herbert, David Ames Jr. Committee Chair
Kuhar, Thomas P. Committee Co-Chair
Hoelmer, Kim A. Committee Member
Pfeiffer, Douglas G. Committee Member
Salom, Scott M. Committee Member
Keywords
  • Pentatomidae
  • Scelionidae
  • biological control
  • efficacy
  • egg chorion
Date of Defense 2010-03-26
Availability restricted
Abstract
Currently, there is little known about stink bug (Hemiptera: Pentatomidae) eggs,

their natural enemies, and their susceptibility to insecticides.

A survey of stink bug egg parasitoids was conducted in row crops and vegetables

in eastern Virginia. Parasitization was highest in Euschistus servus (Say) with 89.7% and

49.2% of egg masses and individual eggs parasitized, respectively, followed by

Acrosternum hilare (Say), with nearly half of all individual eggs parasitized. The most

common parasitoid was Telenomus podisi Ashmead (Hymenoptera: Scelionidae).

Laboratory egg-dip bioassays and field applications of acephate, lambda-cyhalothrin,

spinosad, and thiamethoxam, were carried out to determine efficacy against nonparasitized

E. servus and A. hilare eggs, and T. podisi embryos developing in E. servus

eggs. Results showed that eggs of both species were susceptible to insecticides, that there

was little difference among insecticides, but there was generally greater mortality in

field-treated versus dipped eggs. Developing T. podisi were generally more susceptible

to insecticides than stink bugs.

Scanning electron microscopy was used to investigate oviposition sites as possible

sites of insecticide movement into eggs. Oviposition wounds and holes made by a

tungsten probe were similarly sealed by a “scab”, so it was not clear whether these

wounds allow for increased insecticide movement into parasitized eggs.

Differences in chorion permeability of non-parasitized and parasitized eggs were

compared by immersing them in solutions containing different 14C-ammended

insecticides at field application rates for 0, 30, 120 or 240 minutes. Results showed that

insecticide movement into the egg increased significantly with immersion time for both

acephate and lambda-cyhalothrin, but there were no significant differences between nonparasitized

and parasitized eggs. Neither immersion time nor egg status was significant

for thiamethoxam. A model was constructed that predicts amount of insecticide entering

the egg at any given time.

An 8-week survey for the brown marmorated stink bug, Halyomorpha halys (Stål)

was conducted in Beijing and five other cities in China. Incidence of egg parasitism was

recorded. Results showed that H. halys utilized at least four different plants throughout

the summer, and insects were found in Nanjing, Kunming, and Xi’an. Parasitization of

eggs was noted, and the parasitoids were identified as Trissolcus halyomorphae Yang

(Scelionidae: Hymenoptera) by K.A. Hoelmer (USDA-ARS).

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