Journal of Economic Entomology (1996) 89, 97-103

H.Y. Choo, A.M. Koppenhöfer and H.K. Kaya (1996)
Combination of two entomopathogenic nematode species for suppression of an insect pest
Journal of Economic Entomology 89 (1), 97-103
Abstract: Laboratory and greenhouse studies were conducted to determine whether combining 2 entomopathogenic nematode species would result in synergistic, additive, or antagonistic effect against 2nd-stage larvae of the western spotted cucumber beetle, Diabrotica undecimpunctata undecimpunctata Mannerheim. After an initial screening of I2 nematode species/strains, the most efficacious Steinernema and Heterorhabditis and 2 Steinernema species that were intermediate in effectiveness were selected for further evaluations. In laboratory soil bioassays, the lethal concentration resulting in 50% mortality (LC₅₀) for the most virulent nematode, Steinernema carpocapsae (Weiser) All strain, was 14.5 infective juveniles followed by 18.4 infective juveniles for Heterorhabditis bacteriophora Poinar NCI. strain, 48.1 infective juveniles for S. riobravis Cabanillas, Poinar and Raulston Texas strain, and 98.6 IJs for Steinernema sp. Hanrim strain. Combining 2 of the 4 nematode species at the LC₂₅ values always resulted in an additive effect, regardless of the effectiveness of the individual nematode species. In the greenhouse, application of S. carpocapsae, S. riobravis, Steinernema sp., or H. bacteriophora was made alone or in paired combinations at the rates of 1 x 10⁸ and 2.5 x 10⁸ infective juveniles/ha against western spotted cucumber beetle larvae. At both rates, the most efficacious single nematode species against the larvae was S. carpocapsae. The combination of 2 nematode species showed variable results. Its efficacy ranged between as high as the better of the 2 combined species alone and as low as the less effective of the 2 species alone. In addition, the combined nematode treatments were always less effective than the most efficacious single nematode species, S. carpocapsae. We conclude that no advantage was gained by combining 2 entomopathogenic nematode species against western spotted cucumber beetle larvae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Harry K. Kaya, Albrecht M. Koppenhöfer, Ho Yul Choo

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
application technology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diabrotica undecimpunctata
Steinernema carpocapsae/Xenorhabdus nematophila (entomopathogen)	Diabrotica undecimpunctata
Heterorhabditis bacteriophora/Photorhabdus (entomopathogen)	Diabrotica undecimpunctata