Impact of Oleylamine-Coated ZnO NPs and ZnO-Geraniol Nanocapsules on the Control of the Herbivore Tuta absoluta in Tomato Plants

Among the new horizons that nanomaterials open, nano-agrochemicals are able to improve agricultural production by increasing the efficiency of inputs and minimizing relevant losses. In the present study, primary hydrophobic ZnO NPs coated with oleylamine have been prepared, physicochemically characterized and used as building moieties in combination with the insect repellent, geraniol, in 1:2 mass ratio respectively., for the formation of the secondary nanocapsules. Multiple important biological activities are known for the essential oil geraniol. The prepared nanosystems ZnO@OAm NPs., ZnO@OAm@Ger NCaps as well as geraniol nanoemulsions (GNEs) were tested for their insecticidal activity against the herbivore Tuta absoluta in tomato plants. The LC50 value for the ZnO@OAm NPs was calculated at 29.11mg/L while the NCaps and GNEs exhibited almost the same and much higher LCso values at about 286 mg/L. The significantly different insecticidal behavior., up to now., is attributed to nanosize effects as well as to the hydrophobicity/hydrophilicity balance of the studied nanosystems.