Journal of Apicultural Research
Syrphids (order Diptera, family Syrphidae) were numerically the dominant visitors on umbels of flowering parsley. Honeybees were the next most numerous, and their numbers increased through-out the bloom period, while the syrphids showed a large population decline prior to mid-bloom. Seed yields were nearly 3 times as great with open pollination as when pollinators were excluded from the flowers. Seed set, an expression of pollinating activity, was maximum during weeks 2,3,4 of a 5-week bloom period.
Burgett, Michael, "Pollination of Parsley (Petroselinum Crispum) Grown for Seed" (1980). Bu. Paper 15.
Available for download on Saturday, January 01, 2050