Susceptibility of Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) to cyantraniliprole and spinetoram

• Published in: Biocontrol science and technology 2024-10, Vol.34 (10), p.859-874
• Main Authors: Souza Sarmento Moraes, Rian Javé, Silva-Torres, Christian S. A., Barbosa, Paulo R. R.
• Format: Article
• Language: English
• Subjects: Agricultural practices; Biological control; Brassica; chemical control; Chemical pest control; Crops; Diamondback moth; insecticide selectivity; Insecticides; Integrated approach; Integrated pest management; Larvae; Nontarget organisms; Pest control; Pesticides; Pests; Residues; Spraying; Survival; Tetrastichus
• ISSN: 0958-3157; 1360-0478
• DOI: 10.1080/09583157.2024.2391316

Integrated pest management (IPM) uses a range of control strategies to diminish pest populations. Hence, the simultaneous utilisation of synthetic insecticides and biological control agents is desirable, although hindered by the possible impact of insecticides on non-target organisms. Plutella xylostella (L.) is a common target of several pesticides in Brassica crops. However, it can also be parasitised by Tetrastichus howardi (Olliff). This study examined the susceptibility of T. howardi to dry residue of cyantraniliprole and spinetoram on inert surfaces and treated kale (Brassica oleracea var. manteiga) leaf discs at field rates (FRs = 10 g a.i. ha −1 and 25 g a.i. ha −1 , respectively), 50% of the FR, and at various time intervals (ranging from 2 h to 8 days after application). Survival of T. howardi remained unaffected by cyantraniliprole and spinetoram, regardless of the pesticide rate or spraying interval. Furthermore, the presence of cyantraniliprole and spinetoram in dry residue, when kale leaves were consumed by second-instar P. xylostella larvae at LC 25 and LC 50 levels, did not have any detrimental impact on the survival of the parasitoids. Similarly, the exposure of T. howardi to contaminated P. xylostella larvae did not have any impact on its ability to parasitise or on the emergence of the parasitoid. Given the minimal effect of cyantraniliprole and spinetoram on T. howardi, these control strategies appear to be suitable for incorporation into an integrated approach for the management of P. xylostella in Brassica crops.