Insecticidal and Enzyme Inhibitory Activities of Isothiocyanates against Red Imported Fire Ants, Solenopsis invicta

Abstract

Contact and fumigation toxicity of four isothiocyanates (ITCs), including allyl isothiocyanate (AITC), 3-butenyl isothiocyanate (3BITC), 3-(methylthio) propyl isothiocyanate (3MPITC) and 2-phenylethyl isothiocyanate (2PEITC), were evaluated against the red imported fire ant worker, Solenopsis invicta Buren. 2PEITC and 3MPITC exhibited strong contact toxicity. The median lethal dose (LD50)value of AITC, 2PEITC and 3MPITC were 7.99, 2.36 and 2.09 µg/ant respectively. In addition, AITC and 3MPITC also showed strong fumigation toxicity but not 2PEITC. The median lethal concentration (LC50) values of AITC and 3MPITC were 32.49 and 57.6 µg/L, respectively. In contrast, 3BITC did not exhibit any contact and fumigation toxicity even at 100 μg/μL. Esterase (EST), glutathione S-transferase (GST) and acetylcholinesterase (AChE)-inhibiting activities were assessed for three ITCs in S. invicta workers. All three ITCs inhibited both EST and GST activities but not AChE. The in vitro half maximal inhibitory concentration (IC50)values of AITC, 2PEITC and 3MPITC for GST were 3.32, 0.61 and 0.66 µg/µL, respectively. These results suggested that naturally occurring ITCs might be potentially useful for developing fire ants control products.

Role of Insect Gut Microbiota in Pesticide Degradation: A Review

“…Consequently, various biological and ecological factors mediate several available reports on insect pests’ resistance against different pesticides ( Table 1 ). As a result of the overdependence on synthetic pesticides, numerous concerns have been raised in lieu of their side effects, such as the development of resistance in the target insects, the pollution of the environment, and the effects on human health ( Du et al, 2020 ). It has also been suggested that pesticide resistance may be influenced by gut microbiota, which adds another degree of complexity to the processes of resistance ( Gressel, 2018 ).…”

Naturally Occurring Compounds/Materials as Alternatives to Synthetic Chemical Insecticides for Use in Fire Ant Management

“…Many naturally occurring organic compounds/materials have been assessed for their contact toxicity against fire ants (Table 4), including defensive compounds from other ants [55][56][57], anuran skin alkaloids [58], plant raw materials, plant extracts and essential oils and their individual components [45,[59][60][61][62][63][64][65][66][67]. Soil containing cinnamon leaf debris [62] *: In some studies, the contact and fumigation toxicities of test compounds/materials were not well separated due to the experimental design.…”

“…Fire ants were first detected in Japan in a shipping container from China in May 2017. Allyl isothiocyanate, a naturally occurring compound, is a potent fumigant against fire ants [61]. Fumigation using microencapsulated allyl isothiocyanate pellets in a gas-barrier bag was tested in Japan [105].…”

Comprehensive Detoxification Mechanism Assessment of Red Imported Fire Ant (Solenopsis invicta) against Indoxacarb

“…Chemical pesticides are heavily utilized to manage various invasive ants in the current era. Despite their effectiveness, numerous questions have been raised about the side effects of these synthetic insecticides, such as developing resistance in target insects, pollution of the environment, and negative influence on human health [ 17 ]. In China, several synthetic chemical products have been registered to manage S. invicta [ 4 ].…”