Pathogenicity of three entomopathogenic nematodes against the onion thrips,Thrips tabaciLind. (Thys.; Thripidae)

Abstract

Pathogenicity of a native isolate of Steinernema feltiae (H1) and two exotic strains, Heterorhabditis bacteriophora and Steinernema carpocapsae was assessed under laboratory conditions using different concentrations i.e. 4000, 6000, 8000 and 10,000 infective juveniles/ml against second instar larvae, prepupa and pupa of Thrips tabaci Lindeman. The mortality data were recorded 24 and 48 h post-inoculation. The highest mortality rate was recorded for prepupa (62%) than second instar (12.5%) by H. bacteriophora and S. carpocapsae, respectively, 24 h after treatment. No significant differences were found in mortality between prepupa and pupa with increasing the nematodes concentrations (from 4000 to 10,000 nematode/ml) but increasing nematode concentrations increased the mortality of second instar. At the end of the experiment (48 h.), S. feltiae H1 caused the highest mortality on second instar larvae (74%), whereas all other species caused 80-83% mortalities on pupa. This study suggests that native isolate of S. feltiae (H1) had high potential to infect soil-dwelling stages of T. tabaci.

Potential of different entomopathogenic nematode strains in controlling Atrijuglans hetaohei Yang (Lepidoptera: Heliodinidae)

“…The pupae of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) also were found to be susceptible to eight EPN species according to Gulzar et al (2021). The highest susceptibility of pupae may be due to their lack of mobility (Saffari et al 2013). In this study, the newly cocooned mature larvae of A. hetaohei could be infected by nematodes as well as mature larvae because of their loose cocoon structure.…”

“…In order to achieve the best control result, the nematodes should be applied at the most susceptible stage of different host (Nikdel et al 2010). Saffari et al (2013) observed a great mortality of prepupae and pupae of Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) compared to 2nd instar larvae when applying Steinernema feltiae (Rhabditida: Steinernematidae), H. bacteriophora, and S. carpocapsae. The pupae of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) also were found to be susceptible to eight EPN species according to Gulzar et al (2021).…”

Nematode Pathogenesis of Insects and Other Pests

“…In 2000 Saffari, Madadi, and Karimi (2013) In another study, Ebrahimi, Niknam, and Lewis (2011) assessed the lethal and sub-lethal effects of two isolates of S. feltiae and H. bacteriophora against the prepupae of CPB in soil at two different temperatures. Their results revealed that both isolates were effective against L. decemlineata although H. bacteriophora was more effective at lower concentrations than S. feltiae.…”

“…Moreover, pathogenicity and repro-ductive potential of H. bacteriophora on the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae) was investigated under laboratory conditions and it was showed that common earwig could be suitable or alternative host for H. bacteriophora (Kordestani et al, 2013). Saffari et al (2013) evaluated the pathogenicity of a native isolate of S. feltiae (H1) and two exotic isolates, H. bacteriophora and S. carpocapsae against second instar larvae, prepupa and pupa of the onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae) under laboratory conditions. Their results indicated that prepupa was the most susceptible stage, while the second instar larvae showed the least susceptibility to EPNs.…”

Efficacy of entomopathogenic fungi, nematodes and spinetoram combinations for integrated management of Thrips tabaci

“…The nematodes kill insect hosts with the assistance of symbiotic bacteria 27 . Earlier studies documented that EPNs displayed high control potential against different species of thrips 28–35 . A few studies have achieved significantly higher mortality rates of T. tabaci when exposed to EPNs 31,33–35 .…”