Side effects of insecticides applied to cotton on adult Trichogramma pretiosum by three exposure routes

• Published in: Pest management science Vol. 78; no. 5; pp. 1895 - 1902
• Main Authors: Costa, Mariana Abreu, Farias, Elizeu Sá, Passos, Luis Clepf, Carvalho, Vinicius Castro, Carvalho, Geraldo Andrade
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-05-2022; Wiley Subscription Services, Inc
• Subjects: Animals; Bioassays; Biocompatibility; Biological control; Biological effects; Chlorfenapyr; Cotton; ecotoxicology; Exposure; Female; Gossypium; Gossypium hirsutum; Hymenoptera; Incompatibility; Ingestion; insecticide growth regulator; Insecticides; Insecticides - toxicity; IOBC toxicity category; Methomyl - pharmacology; Moths; Offspring; Parasitism; Pest Control, Biological; Residues; risk assessment; Side effects; Spraying; Survival; Thiodicarb; Toxicity; Trichogramma pretiosum; Wasps; risk assessment; IOBC toxicity category; Gossypium hirsutum; insecticide growth regulator; ecotoxicology
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6807

BACKGROUND
Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is released in extensive areas cultivated with cotton worldwide, but the use of synthetic insecticides threatens the establishment of augmented populations. Thus, an assessment of insecticides’ effects on T. pretiosum is required to establish their compatibility with mass releases of the parasitoid. We studied in the laboratory the impact of insecticides administered through different exposure routes (direct‐spraying, ingestion and residue contact) on T. pretiosum. Based on their toxicity, the insecticides were rated into four categories (harmless, slightly harmful, moderately harmful and harmful) as per the International Organization for Biological Control.
RESULTS
The survival, parasitism ability and emergence of the treated adults and offspring (F1 and F2), in addition to the persistence of the toxic effects in semi‐field conditions, were assessed. Teflubenzuron did not reduce female survival and caused a lesser impact on T. pretiosum on both direct‐spraying and ingestion bioassays. In the residue contact bioassay, teflubenzuron and flupyradifurone were rated as harmless and slightly harmful, respectively. The other active substances (chlorfenapyr, thiodicarb and methomyl) were harmful to the parasitoid by all exposure routes and were persistent (with toxicity duration surpassing 30 days).
CONCLUSION
From these findings, teflubenzuron is the insecticide most compatible with T. pretiosum releases and should be preferred over the other active substances. Further studies with the harmful insecticides (thiodicarb, chlorfenapyr and methomyl) are required to determine their toxicity under field conditions and confirm their incompatibility with T. pretiosum releases.
Insecticides were tested on Trichogramma pretiosum by three exposure routes (direct‐spraying, ingestion and residue contact) and rated as per IOBC. Teflubenzuron is more compatible with T. pretiosum releases, followed by flupyradifurone.
© 2022 Society of Chemical Industry.