Evaluation location: Washington, United States
In conjunction with efforts to identify efficient insect pollinators for seed multiplication of cross-pollinated plant species stored and maintained by USDA, ARS Western Regional Plant Introduction Station (WRPIS), experiments were conducted to assess and compare the efficiency of the house fly (HF) Musca domestica L. and the bottle fly (BF) Calliphora vicina Robineau-Desvoidy, and different densities of each fly species, to pollinate leek, Allium ampeloprasum L., plant inventory (PI) accessions in field cages for seed yield maximization and high germination. Cages with flowering plants were exposed to 0 flies or stocked with 100, 250, and 500 HF or BF pupae per week for six (2002) and seven (2004) weeks. Seed yield (weight per cage) increased linearly as fly densities (BF or HF) increased from 0 to 500 pupae per week, with 500 fly cages averaging 340.73 g (BF) and 70.45 g (HF) of seed in 2002 (PI 368343) and 615.34 g (PI 168977) and 357.52 g (PI 368343) in 2004 when only the BF was used. For 0, 100, and 250 fly cages, seed yields averaged between 2.25 and 175.29 g in 2002 and 10.66 and 273.05 g in 2004. Mean 100-seed weights between treatments ranged narrowly between 0.40 and 0.45 g in 2002 and 0.33 and 0.39 g in 2004 and germination rates of seed lots from `fly cages' were mostly greater than or equal to 80% in both years.