Mrežasta stjenica platane Corythuca ciliata Say (Hemiptera: Tingidae) značajan je štetnik platane. Stjenice sišu na listovima čime smanjuju fiziološke funkcije, izazivaju žućenje listova, a za jakog napada uzrokuju i preranu defolijaciju platana. Također su i neugodan molestant u urbanim sredinama. Suzbijanje štetnika otežano je zbog veličine krošnje i opasnosti za zdravlje ljudi i životinja uslijed primjene insekticida, stoga se sve više pozornosti pridaje ekološki prihvatljivijim mogućnostima suzbijanja. U radu je istraživana učinkovitost smanjenih doza biološkog insekticida na bazi prirodnog piretrina u suzbijanju mrežaste stjenice platane. Uz preporučenu dozu, istraživana je učinkovitost ½ doze, 1/5 doze, 1/10 doze, te 1/20 preporučene doze navedenog preparata tijekom laboratorijskog pokusa. Rezultatima je dokazana učinkovitost višestruko smanjenih doza piretrina što upućuje na visoku djelotvornost ovog ekološki povoljnijeg sredstva što je od izuzetne važnosti kod planiranja zaštite u urbanim sredinama gdje je povećana opasnost od kontaminacije ljudi i kućnih ljubimaca uslijed primjene kemijske mjere zaštite bilja.; The sycamore lace bug Corythuca ciliata Say (Hemiptera: Tingidae) is a significant pest of sycamore. Bugs suck on the leaves, which reduces physiological functions, causes yellowing of the leaves, and for a strong attack, they cause premature defoliation of sycamore trees. They are also uncomfortable molestants in urban areas. Pest control is difficult due to the size of the canopy and the danger to human and animal health due to the application of insecticides, so more and more attention is paid to environmentally friendly control. In this paper the effectiveness of reduced doses of biological insecticide based on natural pyrethrin in the control of sycamore lace bug was investigated. In addition to the recommended dose, the efficacy of ½ dose, 1/5 dose, 1/10 dose, and 1/20 of the recommended dose of insecticide was investigated. The results have proven the effectiveness of multiple reduced doses of pyrethrin, which indicates the high effectiveness of this environmentally friendly protection product, which is extremely important when planning protection in urban areas where there is an increased risk of contamination of humans and pets due to chemical treatments.