1. Shapiro-DI; Tylka-GL; Berry-EC; Lewis-LC. 1995.Effects of earthworms on the dispersal of Steinernema spp.
Journal-of-Nematology, 27:1, 21-28; 20 ref.

Previous studies indicated that dispersal of S. carpocapsae may be enhanced in soil with earthworms. The objective of this research was to determine and compare the effects of earthworms on dispersal of other Steinernema spp. Vertical dispersal of Steinernema carpocapsae, S. feltiae and S. glaseri was tested in soil columns in the presence and absence of earthworms (Lumbricus terrestris) dispersal was evaluated by a bioassay and by direct extraction of nematodes from soil. Upward dispersal of S. carpocapsae and S. feltiae increased in the presence of earthworms, whereas upward dispersal of S. glaseri as not affected by earthworms. No significant differences were detected in downward dispersal of S. carpocapsae and S. feltiae in soil with earthworms compared to soil without earthworms. Downward dispersal of S. glaseri, however, was greater in soil without earthworms relative to soil with earthworms. In soil void of earthworms, dispersal of S. glaseri was greatest followed by dispersal of S. carpocapsae. The presence of earthworm burrows in soil did not influence nematode dispersal. Nematodes were recovered from the surface, interior, and casts of earthworms, Therefore, nematodes may have a phoretic association with earthworms.

2. Yamanaka-S; Tanabe-H; Takeuchi-K. Vertical dispersal and infectivity of Steinernema glaseri, S. anomali and S. kushidai (Nematoda: Steinernematidae). Japanese-Journal-of-Nematology. 1995, 25:1, 24-32; 24 ref.

Vertical dispersal, host-finding through movement in sand and infectivity to Galleria mellonella and Popillia japonica in three strains of Steinernema glaseri, S. anomali and S. kushidai were evaluated to determine which nematode species/strain showed the best potential for control of soil-inhabiting insects such as white grubs in turf. The dispersal of S. glaseri £328, S. kushidai and S. carpocapsae was significantly different from S. glaseri £326 and £330 and S. anomali in sand columns without host. Steinernema glaseri £326 and £330 migrated over 10 cm. Over 58% nematodes of S. anomali were recovered from 0-10 cm sections, but a few dispersed deeper. A small portion of S. glaseri £328 and S. kushidai dispersed in the sand column but the majority remained near the top. Three strains of S. glaseri and S. anomali caused higher mortality against G. mellonella than S. kushidai and S. carpocapsae in host-finding through movement in a sand column. Even with the application of 120 infective juveniles of S. kushidai, the mortality, of G. mellonella by this nematode was lower than that by 10 infective juveniles of S. glaseri £326 and £330. In one-on-one assays, G. mellonella mortalities by S. glaseri £328, S. anomali and S. carpocapsae were higher compared with those by S. glaseri £326 and £330, and S. kushidai. The three strains of S. glaseri, S. anomali and S. kushidai were effective against P. japonica at 1000 infective juveniles/larva. Infectivities to G. mellonella and P. japonica also different among the test nematode species.

3. Timper-P; Kaya-HK; Gaugler-R. 1988. Dispersal of the entomogenous nematodes Steinernema feltiae (Rhabditida: Steinernematidae) by infected adult insects. Environmental-Entomology. 1988, 17:3, 546-550; 24 ref. Dep. Entomology, Univ. California, Davis, CA 95616, USA.
Adults of the noctuid Spodoptera exigua infected with the entomophilic nematode Steinernema feltiae [Neoaplectana carpocapsae] were observed to disperse up to 11 m from the site of infection in the laboratory. After dispersal and death of the host, nematode progeny developed within the moth cadavers, moved into the soil and infected larvae of the host. There was no significant difference between N. carpocapsae (All strain, 16.2 h), N. carpocapsae (Mexican strain, 15.6 h) and Heterorhabditis heliothidis (NC strain, 15.0 h) in either the proportion of pupae and adults of S. exigua infected or the longevity of infected adults. It is concluded that the dispersal of N. carpocapsae by infected adult insects may account in part for local and worldwide distribution of this and other entomogenous nematodes.