Interactions between entomopathogenic nematodes and imidacloprid for rose sawfly control |
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Authors: | H Sheykhnejad M Ghadamyari AM Koppenhöfer |
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Institution: | 1. Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran;2. Department of Entomology, Rutgers University, New Brunswick, NJ, USA |
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Abstract: | Rose sawfly, Arge ochropus (Gmelin), is one of the most important pests of ornamental plants such as roses and wild rose bushes in Northern Iran. We investigated the interactions between the insecticides imidacloprid and the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae as control agents of fifth-instar larvae in the laboratory. The larvae were very susceptible to S. carpocapsae (LC50: 21 infective juvenile per larva) and H. bacteriophora (LC50: 32). Combinations of two imidacloprid rates (LC30 and LC50) and four rates of each nematode species (LC25–LC75) were tested. Combinations with the lower imidacloprid rate except for that with the highest H. bacteriophora rate caused higher mortality than both respective single-agent treatments. In combination with the higher imidacloprid rate, only one combination with H. bacteriophora and two combinations with S. carpocapsae caused higher mortality than both respective single-agent treatments. Interactions were generally stronger at the lower imidacloprid rate and were stronger for S. carpocapsae (synergistic in seven combinations, additive in one) than for H. bacteriophora (synergistic in two, additive in six). Synergistic imidacloprid-S. carpocapsae combinations could be a useful tool for the control of A. ochropus larvae that would simultaneously control other common pests susceptible to imidacloprid. |
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Keywords: | Arge ochropus entomopathogenic nematodes biological control synergism insect pathology |
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