Black plum sawfly (Hoplocampa minuta) is an important pest species of plum (Prunus domestica). In organic plum orchards, the yield loss caused by H. minuta larval damage can reach almost 100% occasionally. Adults feed on pollen and nectar of the plum flower; therefore, we hypothesize that, besides visual cues, also olfaction plays an important role in habitat and host finding. To understand the chemical communication mediated by flower volatiles to black sawflies, we investigated the chemical signals released from plum flowers, which can trigger the peripheral physiological responses of adult sawflies. First, using gas chromatography coupled with electroantennography (GC-EAD), we selected 18 physiologically active compounds from the headspace volatile collection of plum flowers, which triggered the H. minuta male and female antennae. Subsequently, we determine the volatilome of plum flower and identified those compounds, which elicited physiological responses, using gas chromatography coupled with mass spectrometry (GC-MS). These antennally active components in flower volatiles could be candidates for potential kairomone, which could later be used for attracting males and females of H. minuta and could contribute to developing pesticide-free, effective monitoring and lure and kill strategy against this pest.
Authors:Zsolt Kárpáti, Csengele Bognár, Erzsébet Voigt, Miklós Tóth, and Béla Péter Molnár
Three sawfly species (Hoplocampa minuta, Hoplocampa flava, Hoplocampa fulviicornis) have been monitored in plum orchards during the flowering period in three consecutive years at three different locations in Hungary using chromotropic white sticky traps. Black and yellow sawflies (H. minuta and H. flava) are one of the most important pests in plum orchards, however plum-fruit sawfly (Hoplocampa fulvicornis) has not yet been documented from plum orchards in Hungary. In almost all locations and years, H. minuta was the most dominant species, except in Cegléd, 2014, where H. flava was the most abundant one. In terms of sex ratio, in all three species, more males than females were caught in the traps except in 2016 at Érd, where more H. flava females flew into the traps.