Entomopathogenic Nematode Management of Small Hive Beetles (Aethina tumida) in Three Native Alabama Soils Under Low Moisture Conditions
Type of DegreeMaster's Thesis
Entomology and Plant Pathology
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The overall goal of this work was to determine the efficacy of entomopathogenic nematodes (EPNs) on Aethina tumida Murray (Coleoptera:Nitidulidae) small hive beetle (SHB) in different soil types under low moisture conditions to improve current integrated pest management practices. The objectives were to 1) determine the pupation success of SHB wandering larvae in natural non-autoclaved and sterile autoclaved soil; 2) determine the efficacy of EPNs on SHB wandering larvae in natural non-autoclaved and autoclaved soil in low moisture conditions; and 3) determine the efficacy of EPNs on SHB wandering larvae in three natural non-autoclaved soil types at low moisture levels. The Alabama soils we tested were Kalmia loamy sand (KLS), Benndale fine sandy loam (BFSL), and Decatur silt loam (DSL). For this work, commercially purchased Heterorhabditis bacteriophora Poinar, Steinernema feltiae Filipjev, and Steinernema kraussei Steiner, as well as commercially purchased and laboratory reared Heterorhabditis indica Poinar, Karunaka & David, Steinernema carpocapsae Weiser, and Steinernema riobrave Cabanillas, Poinar & Raulston were tested. We evaluated population densities of 5%, 10%, 20%, 40%, and 80% third stage infective EPN juveniles (IJ3) per 130cc soil. In objective one, pupation success in SHB population densities of 5, 10, and 20 wandering larvae per Petri dish in KLS were similar. Thus, for objectives two and three we used a SHB population density of 5 SHB wandering larvae per Petri dish. Objective two evaluated six commercially purchased and laboratory reared EPN species in natural non-autoclaved and autoclaved KLS soil. Of the six commercially purchased species, S. carpocapsae achieved the highest efficacy across all EPN population densities and in both natural non-autoclaved and autoclaved soil with the 69.4% and 84.1% efficacy, respectively. Steinernema riobrave and H. indica achieved the next highest efficacies, however, they were significantly less effective that S. carpocapsae. Of the laboratory reared EPNs, the highest efficacy for S. carpocapsae, S. riobrave, and H. indica was achieved at the population density of 80% IJ3 per 130cc soil. Steinernema carpocapsae parasitized 86.7% SHB wandering larvae across all population densities tested. The third objective included all three soil types at the moisture content of 50% field capacity for each soil. At the highest population density, S. carpocapsae achieved the best efficacy in KLS, BFSL, and DSL soils at 94.0%, 80.0%, and 47.0%, respectively. In all low moisture EPN experiments, efficacy of each EPN species on SHB wandering larvae was improved when higher EPN population densities were applied. In conclusion, this work suggests that S. carpocapsae could be a promising biological control agent to implement into an integrated pest management system for control of SHB in Alabama during low moisture conditions.