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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Publications at this Location » Publication #388450
Title: Laboratory bioassays of a native Arkansas isolate of Metarhizium robertsii (Bischoff, Rehner and Humber) (Hypocreales: Clavicipitaceae) and the biopesticide Met52®

Author
item Goldsmith, Austin
item LOFTIN, KELLEY - University Of Arkansas
item STEINKRAUS, DONALD - University Of Arkansas
item SZALANSKI, ALLEN - University Of Arkansas
item Sampson, Blair

Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2023
Publication Date: 3/2/2023
Citation: Goldsmith, A.T., Loftin, K., Steinkraus, D., Szalanski, A., Sampson, B.J. 2023. Laboratory bioassays of a native Arkansas isolate of Metarhizium robertsii (Bischoff, Rehner and Humber) (Hypocreales: Clavicipitaceae) and the biopesticide Met52®. Journal of Agricultural and Urban Entomology. https://doi.org/10.3954/JAUE22-10.
DOI: https://doi.org/10.3954/JAUE22-10

Interpretive Summary: The lone star tick is a long-lived pest that feeds on people and animals and at its worst can spread debilitating diseases. This study shows that two soil-borne insect-killing fungi can also infect and kill the adults and immatures of the lone star tick in the southeastern United States. A commercially available fungus (Met52) ultimately killed every treated tick within 77 days. A native Arkansas fungal strain (Savoy P10N1), a species closely related to Met52, killed 25% of adults and 33% of immature ticks after 77 days. Although, the Savoy strain killed fewer ticks than did Met52, further refinement of the formulation should improve rates of tick mortality. However, these data do show that fungal pathogens are a viable and environmentally-safer option for integrated tick management.

Technical Abstract: The rise of tick encounters and the incidence of tick-borne diseases necessitates the use of alternative tick control strategies. The lone star tick, Amblyomma americanum L. (Acarina: Ixodidae), feeds on a wide range of mammalian hosts and is implicated as a major vector of pathogens affecting humans, livestock, and companion animals. This study presents a laboratory bioassay evaluating the effectiveness of an Arkansas isolate of Metarhizium robertsii (Bischoff, Rehner and Humber) (strain Savoy P10N1 [ARSEF 14329]) to that of a commercial mycoinsecticide, Met52® (M. brunneum [Petch] strain F52), for managing A. americanum. Mortality of adults treated with Met52® at day 14 post-inoculation (d PI) was 25.3 ± 8.3% and reached 100% by 70 d PI. In comparison 0.8 ± 0.4 and 18.4 ± 6.8% mortality was observed for Savoy P10N1 at 14 d PI and 70 d PI respectively. Nymphs were particularly susceptible to Met52® with 92.3 ± 4.7 % mortality observed at 2 d PI when compared with the 5.3 ± 3.3 % of nymphs killed at 14 d PI for Savoy P10N1. Although Met52® caused higher mortality than Savoy P10N1 in both A. americanum adults and nymphs, both stages of this tick were to some degree susceptible to both Metarhizium species. Additional research is needed to find and evaluate isolates of entomopathogenic fungi for the control of A. americanum.