Evaluating the Effectiveness of Insecticides on Spotted Lanternfly Lycorma delicatula (Hemiptera: Fulgoridae) in Kiwifruit.

Abstract

The spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), has invaded several countries and caused significant losses to agricultural economy, especially in grapes, apples and kiwifruit production. Currently, chemical control is the primary method for managing this pest. In this study, we tested the contact toxicity of bifenthrin and lime sulphur on SLF eggs, as well as the residual toxicity of natural pyrethrins, bifenthrin, and thiacloprid on SLF nymphs. The results showed that bifenthrin, applied at 100 times the label rate, had the highest lethal effect on SLF eggs, with an adjusted mortality rate of 71.8 ± 8.5%. The addition of a penetrant, Engulf, did not further enhance ovicidal efficacy. For nymphs, the residual effect of thiacloprid and bifenthrin at label rates demonstrated 100% mortality within 48 h in laboratory bioassays. Similar efficacies were observed in short-term field experiments. However, the efficacy of bifenthrin declined significantly over time, while thiacloprid provided a long-lasting control, with mortality rates of 72.8 ± 5.9% and 46.7 ± 7.2% at 7 and 14 days, respectively. Although the combination of pyrethrins and mineral oil exhibited limited efficacy, with a 0-day (test immediately after the sprayed branches have dried) mortality rate of 41.5 ± 12.5%, its favourable environmental safety profile makes it a viable option for organic control strategies. In conclusion, bifenthrin at 100 times the label rate was the most effective against SLF eggs, while thiacloprid at label rates provided the longest-lasting control against SLF nymphs.