Productivity performance of peach trees, insecticidal and antibacterial bioactivities of leaf extracts as affected by nanofertilizers foliar application

Abstract

The current study was performed on eight years old peach (Prunus persica L. Batsch) trees cv. Florida prince to study the influence of spraying of commercial nano fertilizer on vegetative growth, pollen grain viability, yield, and fruit quality of the "Florida prince" peach cultivar. Furthermore, extracts from the nanofertilizer treated leaves were studied for their bioactivity as insecticidal or bactericidal activities against some stored grain insects and plant bacterial pathogens. Seventy uniform peach trees were sprayed three time as follow: before flowering; during full bloom, and one month later in addition using the water as a control. Commercial silver particales (Ag NPs) at 10, 12.5, and 15 mL/L and zinc particales (Zn NPs) at 2.5, 5 and 7.5 mL/L as recommended level in a randomized complete block design in ten replicates/trees. Spraying Ag NP at 15 mL/L increased shoot diameter, leaf area, total chlorophyll, flower percentage, fruit yield and fruit physical and chemical characteristics, followed by Ag NPs at 12.5 mL/L and Zn NPs at 7.5 mL/L. Moreover, Zn and Ag NPs caused a highly significant effect on pollen viability. Different type of pollen aberrations were detected by Zn NPs treatment. The commercial Ag NPs showed a high increase in pollen viability without any aberrations. The Ag NPs significantly increased the pollen size, and the spores also increased and separated in different localities, searching about the egg for pollination and fertilization. Peach leaves extract was examined for their insecticidal activity against rice weevil (Sitophilus oryzea L.) and the lesser grain borer (Rhyzopertha dominica, Fabricius) by fumigation method. The antibacterial activity of all treatments was also performed against molecularly identified bacteria. Ag NPs treated leaves extract at concentration 3000 µg/mL were moderate sufficient to inhibit all the bacterial isolates with inhibition zone (IZ) ranged 6–8.67 mm with high efficiency of acetone extracts from leaves treated with Ag NPs compared with Zn NPs. Also, S. oryzae was more susceptible to acetone extracts from leaves treated with both nanomaterials than R. dominica.