Physiological selectivity of insecticides to adult of Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae)

Abstract

Doru luteipes (SCUDDER, 1876) is considered one of the best natural enemies of the fall armyworm Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), feeding on their eggs and small caterpillars. For its conservation it is necessary to use selective insecticides to S. frugiperda and harmless to the predator. Therefore, objective of the present work was to evaluate the toxicity of insecticides registered to control of S. frugiperda. It was conducted bioassays with D. luteipes adults treated with insecticides directly by exposure to residues of compounds applied on glass plates and the consumption of eggs of S. frugiperda contaminated and offered each one, 24 and 48 hours after treatment. The insecticides were classified according to indices proposed by IOBC/WPRS. For adults D. luteipes treated directly with insecticides, triflumuron was harmless (class 1); chlorfenapyr and etofenprox as slightly harmful (class 2) teflubenzuron/-cypermethrin and spinosad moderately harmful (class 3) and thiamethoxan/-cyhalothrin harmful (class 4). In bioassay exposure of D. luteipes residues of insecticides applied to glass plates, all products were harmful to the predator, except triflumuron which was considered slightly harmful. The survival of adults after consumption of contaminated eggs was 46.7% for the insecticide tiametoxam/-cialotrina considered slightly harmful to the predator. The other insecticides were innocuous. Due to the low toxicity presented by the triflumuron to the D. luteipes adults, this compound can be recommended in programs aimed at integrated pest management the preservation of this natural enemy. All other products must be evaluated in greenhouse and field to prove its toxicity.

Multiple factors mediate insecticide toxicity to a key predator for cotton insect pest management

“…Similar results were reported for Dorus luteipes (Scudder) preying upon treated eggs of fall armyworm, Spodoptera frugiperda (J.E. Smith)(Redoan et al 2013). Detoxi cation by salivary and digestive enzymes following ingesting (but not after dermal exposure) may explain this outcome (Yu 2004).Pyriproxyfen, regardless of the earwig population or the route of exposure, showed compatibility with adult ring-legged earwigs, as in previous studies(Machado et al 2019;Medina et al 2003).…”

“…Redoan et al 2013). Chlorfenapyr kills by disrupting the proton gradient across mitochondrial membranes, which impairs ATP production and leads to death (Yu 2014).…”

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

“…It is well‐acknowledged that this compound is more toxic by the ingestion route, 50,51 but our findings indicate that T. pretiosum is more susceptible when sprayed directly. Nevertheless, this compound had marked sublethal effects by the oral route, causing striking reductions in F 0 parasitism and F 1 emergence, concurring with earlier reports of deleterious effects of this compound on natural enemies [ Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Doru luteipes (Scudder) (Dermaptera: Forficulidae)] 52,53 …”

“…Nevertheless, this compound had marked sublethal effects by the oral route, causing striking reductions in F 0 parasitism and F 1 emergence, concurring with earlier reports of deleterious effects of this compound on natural enemies [Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Doru luteipes (Scudder) (Dermaptera: Forficulidae)]. 52,53 In the dry insecticide residue bioassay, teflubenzuron (Class 1) was the safest insecticide, followed by flupyradifurone (Class 2). The latter was rated as slightly harmful based on the reduction in the parasitism and did not differ from the negative control in F 1 emergence.…”