Susceptibility of Sunn Pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), to Various Entomopathogenic Nematodes (Rhabditida: Steinernematidae and Heterorhabditidae)

Abstract

The susceptibility of adult sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), to five local Syrian isolates of Heterorhabditis bacteriophora, Steinernema riobravae Texas, S. carpocapsae C3B, and H. bacteriophora 8-14 strains was evaluated under laboratory conditions. Concentrations of 50, 100, 200, and 400 nematodes per adult were bioassayed; for each nematode concentration, four groups of five sunn pests in Petri dishes were used and mortality was recorded daily for five d. The mortality induced by nematodes increased, typically with increasing numbers of nematodes per adult and ranged from 30 to 90%. Overall, Heterorhabditis bacteriophora Musherphe strain produced the lowest mortality and Steinernema riobravae Texas strain produced the highest mortality. The LC(50) values of H. bacteriophora Musherphe, S. carpocapsae C3B, and S. riobrave Texas were 107.1, 66.6, and 65.3 nematodes per adult sunn pest, respectively. LT(50) values ranged from 3.6 to 7.2 d for H. bacteriophora Tabeh-gazira and H. bacteriophora Musherphe strains at 50 nematodes per sunn pest, from 2.9 to 5.1 d for H. bacteriophora Tabeh-gazira and H. bacteriophora Ariha strains at 100 nematodes per sunn pest, from 2.2 to 4.3 d for S. carpocapsae C3B and H. bacteriophora Ariha strains at 200 nematodes per sunn pest, and from 2.0 to 4.3 d for S. riobrave Texas and H. bacteriophora Musherphe strains at 400 nematodes per sunn pest, respectively. Our results suggest that H. bacteriophora Tabeh-gazira, H. bacteriophora El Ratla-1, H. bacteriophora El Ratla-2, H. bacteriophora 8-14, S. carpocapsae M, and S. riobrave Texas strains have potential as biocontrol agents against the sunn pest.