Efficacy of aqueous ragweed extract on Nezara viridula and Halyomorpha halys

Zelena stjenica (Nezara viridula L., 1758) i smeđa mramorasta stjenica (Halyomorpha halys Stål, 1855) su dominantne vrste kukaca iz porodice štitastih stjenica (Pentatomidae) na području Republike Hrvatske dok je ambrozija (Ambrosia artemisiifolia) invazivan i agresivan korov prisutan u čitavoj državi. Cilj istraživanja bio je utvrditi učinkovitost suzbijanja odraslih stadija stjenica vodenim ekstraktom ambrozije. Istraživanje je provedeno u laboratorijskim uvjetima u rujnu 2021. godine u tri tretmana: vodeni ekstrakt ambrozije u koncentraciji 10%, azadiraktin (Ozoneem Trishul® -1%) i voda kao kontrola. Tretmani su postavljeni u četiri ponavljanja te je u pokus ukupno uključeno 240 odraslih jedinki stjenica. Svi tretmani pokazali su blagu toksičnost za ispitivane kukce. Vrsta H. halys bila je osjetljivija na tretman vodenog ekstrakta ambrozije u odnosu na vrstu N. viridula. Statistički značajne razlike mortaliteta odraslih stjenica između tretmana utvrđene su kod vrste H. halys 10 dana nakon tretiranja vodenim ekstraktom ambrozije. Budući da nije utvrđena visoka učinkovitost vodenog ekstrakta ambrozije na odraslim stadijima stjenica istraživanja je potrebno nastaviti i na ličinkama koje imaju viši stupanj osjetljivosti te uz vodene primijeniti i druge vrste biljnih ekstrakata.
Southern green stink bug (Nezara viridula L., 1758) and brown marmorated sting bug (Halyomorpha halys Stål, 1855) are the dominant species from the Pentatomidae family in Croatia, while Ambrosia artemisiifolia L. is an invasive and aggressive weed present throughout the country. The aim of this study was to determine the effectiveness of the aqueous ragweed extract in controlling adult stages of stink bugs. The study was conducted under laboratory conditions in September 2021 in three treatments: aqueous ragweed extract at a concentration of 10%, azadiractin (Ozoneem Trishul® -1%) and water as a control. Treatments were set in four replicates and a total of 240 adults stink bugs (120 N. viridula and 120 H. halys) were included in the experiment. All treatments showed mild toxicity. H. halys was more sensitive to the aqueous ragweed extract compared to N. viridula. Statistically significant differences in mortality between treatments were found in H. halys species 10–14 days after treatment with aqueous ragweed extract. Since no high efficacy of ambrosia extract has been found in the adult stage, research will continue on larvae that have a higher degree of sensitivity to aqueous and ethanolic extracts compared to the adult insect stage.