Examination of commercially available bird feed for weed seed contaminants

Abstract

In 2016 and 2017, 98 separate commercially available bird feed mixes were examined for the presence of weed seed. All weed seed contaminants were counted and identified by species. Amaranthus species were present in 94 of the 98 bags of bird feed. Amaranthus species present in bird feed mixes included waterhemp [Amaranthus tuberculatus (Moq.) Sauer], redroot pigweed (Amaranthus retroflexus L.), Palmer amaranth (Amaranthus palmeri S. Watson), smooth pigweed (Amaranthus hybridus L.), and tumble pigweed (Amaranthus albus L.). Amaranthus palmeri was present in 27 of the 98 mixes. Seed of common ragweed (Ambrosia artemisiifolia L.), kochia [Bassia scoparia (L.) A.J. Scott], grain sorghum [Sorghum bicolor (L.) Moench], wild buckwheat (Fallopia convolvulus L., syn: Polygonum convolvulus), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and Setaria species were also present in bird feed mixes. A greenhouse assay to determine Amaranthus species seed germinability and resistance to glyphosate revealed that approximately 19% of Amaranthus seed in bird feed mixes are readily germinable, and five mixes contained A. tuberculatus and A. palmeri seed that were resistant to glyphosate. Results from linear regression and t-test analysis indicate that when proso millet (Panicum miliaceum L.), grain sorghum, and corn (Zea mays L.) were present in feed mixes, Amaranthus seed contamination was increased. The presence of proso millet and grain sorghum also increased contamination of grass weed species, while sunflower (Helianthus annuus L.) increased A. artemisiifolia contamination and safflower (Carthamus tinctorius L.) increased contamination of Bassia scoparia.

Alien plants of Europe: introduction pathways, gateways and time trends

“…Intentional release for various purposes and transport through contaminants on animals are also important pathways for alien plants into Europe. Moreover, seed contamination should be highlighted as one of the main pathways, in particular for taxa that are alien in Europe, in line with the results of similar studies in Europe ( Ferus et al, 2015 ; Cossu et al, 2019 ) and outside the continent ( Wilson et al, 2016 ; Oseland et al, 2020 ).…”

Amaranthus tuberculatus (Moq) J.D. Sauer

“…Records from ruderal sites in port areas and along (nearby) riverbanks indicate its introduction via imported goods (grain, animal feed mixture). A. tuberculatus has been intercepted in bird feed in the USA (Oseland et al , 2020). In Israel and Romania, it is assumed that the species was introduced by fish food from North America (Greuter & Raus, 1986) and with soybean waste and cereals (Costea, 1996).…”

Pollen-mediated gene flow and transfer of resistance alleles from herbicide-resistant broadleaf weeds

“…The commercial bird-feed trade has been recognized as a pathway for long-distance weed-seed dispersal to new areas. Recent analysis of commercially available birdfeed mixes in the eastern United States found 29 weed species in the mixes (Oseland et al 2020). Amaranthus species were the most common, found in 96% of the mixes; common lambsquarters seed was identified in 10% of the mixes.…”