Semester of Graduation

Summer 2018

Degree

Master of Science (MS)

Department

Entomology

Document Type

Thesis

Abstract

In 2015, emerald ash borer (EAB) was detected in North Louisiana (LA). There is no information on wood inhabiting insects of green ash (Fraxinus pennsylvanica Marshall) trees, phenology and parasitoid establishment in LA. The first objective of the study was to quantify the insect assemblages and to compare their diversity, abundance and evenness within the epicenter of the EAB infestations in North LA including regions in Central and South LA where EAB has not been detected yet. We established four treatments, based on log diameter: small and large; and log condition: dead and live for green ash. All the insects collected bimonthly from emergence traps were identified to family level. A total of 25, 420 insects belonging to 104 families and 11 orders were collected. Assemblages differed among live large trees (Wald test = 8.016, P < 0.01), which composed of greater percentages of Mycetophilidae (Diptera), Megaspilidae (Hymenoptera), Ceratopogonidae (Diptera), and Liposcelididae (Psocodea). Total abundance for live small logs was 11.5-times higher than live large, and 7.7-times higher than dead small logs at non- EAB 1 site due to niche differences. Shannon’s diversity and evenness were found to be higher in dead small, live large, and live small logs at non-EAB 2 site. The potential changes to local ash bottomlands after the EAB invasion in LA are also discussed.

The second objective was to determine the phenology of EAB and establishment of non-native parasitoids. Results focused on life history of EAB suggested the fast development of EAB in LA along with its one generation life cycle in LA. Adults emerged from April to June. EAB larvae appeared earlier in

season including June for L1, L2, L3 and August for L4, Then, J larvae were collected in July until March. These J larvae later pupate (January- March) while some overwinter. Additionally, parasitoid recovery studies did not yield any released parasitoid except one specimen of Oobius agrili (an egg parasitoid) in northern LA. EAB’s fast development, one generation cycle along with regional differences such as subtropical climate in LA compared to the native range of parasitoids would affect EAB biocontrol in LA.

Date

7-5-2018

Committee Chair

Diaz, Rodrigo

Available for download on Sunday, July 04, 2021

Included in

Entomology Commons

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