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Toxicity and sublethal effects of an insecticidal soap on Aphidius colemani (Hymenoptera: Braconidae)
Author(s) -
Tremblay Éléonore,
Bélanger André,
Brosseau Marcel,
Boivin Guy
Publication year - 2008
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.1514
Subject(s) - braconidae , hymenoptera , biology , toxicology , parasitoid , zoology
BACKGROUND: The effects of an insecticidal soap on the survival, fitness and behaviour of an aphid parasitoid wasp, Aphidius colemani (Viereck), were studied in the laboratory. The LC 50 (soap concentration causing 50% mortality 24 h after treatment) was determined. The survival of parasitoid larvae (% adult emergence), fitness (tibia length of adults) and number of eggs produced per female parasitoid that survived in third‐ and fourth‐instar aphids treated with insecticidal soap LC 50 were also assessed. The LC 50 for third‐ and fourth‐instar aphids was determined to be 3.25 g L −1 . Acceptance by female parasitoids of aphids that survived their LC 50 was also tested. RESULTS: The soap concentration causing 100% mortality in adult wasps 24 h after treatment was 17.5 g L −1 . The LC 50 was 2.75 g L −1 . Soap did not have any effect on the survival of parasitoid immatures or on the fitness or number of eggs produced per female parasitoid. Wasps that were in contact with treated aphids did not oviposit as much in them as in untreated aphids, indicating that female parasitoids detected aphids treated with insecticidal soap. CONCLUSION: These data suggest that aphid parasitoids released following treatment with insecticidal soap are likely to accept a lower proportion of the surviving aphids. Biological control programmes could be ameliorated by soap applications if the latter were made 1 day before the release of wasps in the greenhouse. Copyright © 2008 Society of Chemical Industry