Impact of honey bee (Apis mellifera L.) pollination and selected biostimulant extracts on seed production of onion (Allium cepa L.) in New Valley, Egypt

Abstract

This study evaluated the combined effects of honey bee (Apis mellifera L.) pollination and foliar applications of natural biostimulant extracts on onion (Allium cepa L.) seed yield and quality in New Valley Governorate, Egypt, during the 2023 and 2024 seasons. Field experiments employed a randomized complete block design, testing extracts from molasses, licorice, wormwood (Artemisia), and old beeswax combs, alongside water spray, pollinator exclusion (tulle bagged umbels), and an untreated control. Managed Carniolan honey bee colonies facilitated pollination. Honey bee foraging activity displayed significant diurnal variation, peaking between 11:00 and 13:00, with intensity increasing seasonally from March to May, and was positively and negatively correlated with temperature and humidity, respectively. Old beeswax comb extract proved most effective, significantly enhancing bee visitation, yielding the highest seed production (163.8–172.2 kg/ha., representing an over 100% increase compared to the control), the lowest sterility (4.6–6.4%), and the highest germination (94.5–96.3%). Molasses and licorice extracts also markedly improved yield (28–38% increase) and fertilization rates (up to 84.5%). Pollinator exclusion drastically reduced yield and quality, underscoring bees' essential role. Integrating managed honey bee pollination with the application of old beeswax comb extract offers a sustainable strategy to substantially improve onion seed quantity and quality in arid agroecosystems.