Pathogenicity Evaluation of Eight Egyptian Isolates of Entomopathogenic Nematodes against Two Tick Species; Argas persicus and Boophilus annulatus

Abstract

Eight Egyptian isolates of entomopathogenic nematodes (EPN), four belong to the genus Heterorhabditis and four belong to Steinernema were evaluated against adult females of the soft tick Argas persicus and engorged females of the hard tick, Boophilus annulatus in the laboratory. Results indicated that two EPN isolates (A4 and 10k) of Heterorhabditis were rapidly fatal and have high pathogenicity (100% mortality after 72 hours) against A. persicus when treated with 1000 nematode Infective Juveniles (IJs/ml). Meanwhile, only one isolate (5B) of Steinernema gave accumulated mortality of 93.33% against A. persicus. Furthermore, Heterorhabditis isolates (10 K and A4) caused 93.33% and 86% mortality to B. annulatus. The most effective EPN isolates of Steinernema were 5B and AT4 against B. annulatus, they both gave ca 86.7% mortality. The LC 50 values of Heterorhabditis spp. (A4 and 10K isolates) after 72 hrs post infection and LT 50 were (27.03 and 257.03 IJs/ml) and (11.94 and 19.2 hrs.), respectively against A. persicus. While, the LC 90 was 360.24 and 765.72 IJs/ml for A4 and 10K isolates, respectively. Meanwhile, A4 and 10K isolates exhibited relatively high values of LC 50, LC 90 and LT 50 against B. annulatus, represented by (358.57±0.71 and 812.83 IJs/ ml); (1258.9 and 2485.9 IJs/ml.) and (25.64 and 51.28 hrs.), respectively. The present study cleared that Entomopathogenic nematodes (EPN) isolates of the genus Heterorhabditis spp. (A4 and 10K) are potentially useful biological tools for tick control.

Entomopathogenic Nematodes: Integrated Pest Management and New Vistas

“…(B.) annulatus Say (Alekseev et al 2006, EL Roby et al 2018, Ixodes ricinus (L.) (Grewal et al 2001), Anocentor nitens Mohler (Monteiro et al, 2014), and Argas persicus (Oken) (Shamseldean et al 2007(Shamseldean et al , 2008EL Roby et al 2018). Utilizing EPNs against the non-parasitic phase of engorged female ticks can be quite efficient, since engorged females seek as moist environments protected from solar radiation as those settings favorable to EPNs (Grewal et al, 2001).…”

Compatibility of Egyptian strains of entomopathogenic nematodes (Nematoda: Rhabditida) with insecticides and their activity against Spodoptera frugiperda (Lepidoptera: Noctuidae) under laboratory conditions.

“…The emerging infective juveniles (IJs) were collected from nematode traps and stored in sterilized water at 10Cº. [16].…”