Evaluation of chemical and biological control tactics for managing Unaspis euonymi (Hemiptera: Diaspididae) in urban green spaces

The euonymus scale, Unaspis euonymi (Comstock) (Hemiptera: Diaspididae), is a destructive armored scale pest of Euonymus shrubs in urban landscapes, causing aesthetic and physiological damage that is difficult to control due to its protective waxy cover. This study evaluated the performance of multiple control tactics applied in sequence for pest management in Tehran's urban green spaces, Iran. The efficacy of winter emulsifiable oil (۰.۵-۲%) and seven insecticide treatments alone and combined with the oil was tested alongside augmentative releases of the predator Chilocorus bipustulatus L (Coleoptera: Coccinellidae). Results showed that winter oil efficacy was concentration-dependent, with ۲% providing the highest control (۴۱.۷۶%). Among insecticides, the combination of pyriproxyfen (an insect growth regulator) with emulsifiable oil was the most effective treatment, maintaining the highest efficacy (۶۵.۸۱%) over ۱۴ days, highlighting enhanced efficacy when combined. In contrast, imidacloprid was the most ineffective compound. Furthermore, releases of C. bipustulatus provided substantial and increasing suppression, with efficacy rising from ۳۳.۳۳% at seven days after release (DAR) to ۷۴.۷۶% at ۲۱ DAR. The study concludes that a dormant-season application of ۲% emulsifiable oil, the targeted use of pyriproxyfen with oil if necessary, and augmentative releases of C. bipustulatus can provide a scientific basis for developing an integrated management strategy against U. euonymi. Further research is needed to optimize release rates and evaluate long-term efficacy under field conditions.

کلیدواژه ها:

Armored scale ، Augmentative biological control ، Chilocorus bipustulatus ، Pyriproxyfen ، Winter emulsifiable oil