Location: Livestock Arthropod Pests ResearchTitle: Effect of immersion time on efficacy of entomopathogenic nematodes against engorged females of Cattle Fever Tick, Rhipicephalus (Boophilus) microplus Author
|Singh, Nirbhay - Guru Angad Dev Veterinary & Animal Sciences University|
|Shapiro Ilan, David|
|Setamou, Mamoudou - Texas A&M University|
|Perez De Leon, Adalberto - Beto|
Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2017
Publication Date: 3/1/2018
Citation: Singh, N., Goolsby, J., Shapiro Ilan, D.I., Setamou, M., Perez De Leon, A.A. 2018. Effect of immersion time on efficacy of entomopathogenic nematodes against engorged females of Cattle Fever Tick, Rhipicephalus (Boophilus) microplus. Experimental and Applied Acarology. 43(1):19-28. https://doi.org/10.3958/059.043.0120.
DOI: https://doi.org/10.3958/059.043.0120 Interpretive Summary: Six species of parasitic round worms, called entomopathogenic nematodes (EPNs) were tested for their effects on CFT using an adult immersion test. Five engorged female ticks were immersed in a suspension of EPNs for various times (0.5 to 30 min) and tick mortality over time was estimated. The results of the current study demonstrate that infective juvenile EPNs killed engorged cattle fever tick adult females and thus this species has potential as a natural acaricide. One of the species, Steinernema riobrave is native to the the Rio Grande Valley of Texas and has special utility in protected natural areas where conventional acarcides may not be appropriate.
Technical Abstract: Six species of entomopathogenic nematodes (EPNs) were tested for their effects on virulence and reproductive parameters of engorged females of the cattle fever tick, Rhipicephalus (Boophilus) microplus (Deutch strain) using an adult immersion test. The treatments included nematode in the genus Steinernema (Rhabditida: Steinernematidae), S. riobrave (355 strain), S. carpocapsae (All strain) and S. feltiae (SN strain), and Heterorhabditis (Rhabditida: Heterorhabditidae); H. bacteriophora (VS strain), H. indica (HOM1 strain) and H. floridensis (K22 strain). Five engorged female ticks were immersed in a suspension of EPNs at a concentration of 5,000 infective juvenile (IJ)/ml for various time (0.5 to 30 min) and tick mortality over time, egg mass weight, reproductive index (RI) and percentage inhibition of oviposition (%IO) were estimated. The percent mortality was only significantly affected by the nematode species, but immersion time and the species by immersion time interaction were not significant. The Heterorhabditis species caused higher mortality than the Steinernema nematodes with H. floridensis showing the highest efficacy. Both the nematode species and the immersion time had significant effects on RI whereas, the effect of nematode species was not affected by the immersion time. Heterorhabditis species had more pronounced effects on RI with significantly lower values than the Steinernema species. The %IO was only significantly affected by nematode species, but not immersion time and the species by immersion time interaction was not significant. The results of the current study demonstrate that IJs of H. floridensis are most virulent against engorged R. (B.) microplus females and thus this species has potential for biological control of the cattle fever tick.