The Biology of Canadian Weeds. 159.Capsella bursa-pastoris(L.) Medik.

Abstract

Capsella bursa-pastoris (L.) Medik, shepherd’s purse, is a cosmopolitan summer or winter annual weed species distributed throughout temperate and subtropical regions of the world and is considered one of the most common plants on earth. It is an opportunistic annual that colonizes newly disturbed, open or dry environments and is ubiquitous in cultivated lands in Canada. In annual crops in western Canada, C. bursa-pastoris has been among the 20 most abundant weeds since the first weed surveys in 1970. It is most easily distinguished by its small white four-petalled flowers and its heart-shaped seed-pods, but exhibits considerable variation in leaf shape and flowering time. It has been used for food and medicine by numerous cultures. Its golden-brown seeds are produced in large numbers predominantly through self-pollination and can form a substantial seed bank, with reported values ranging to several hundred thousand seeds m-2. While seeds usually disperse near the mother plant, long-distance dispersal by attaching to vehicles, people and other vectors may be facilitated by its mucilaginous coat. Capsella bursa-pastoris does not produce fertile hybrids with other species of economic or ecological significance. It is generally well controlled by soil-applied and foliar (post-emergence) herbicides although its presence in agricultural fields may result in substantial yield loss, as documented in cole crops in North America and grain crops in Europe. The species can host a wide range of insect, nematode, fungal, viral, and bacterial pests that may damage crop species.

Variability structure and heritability of germination timing in Capsella bursa‐pastoris (L.) Medik. (Shepherd's purse)

“…The agricultural populations had a more uniform germination timing, and an earlier T10 and T50, compared to the non-agricultural populations. Both agricultural populations likely faced mortality events due to intensive tillage and herbicide regimes that consistently occurred at similar times every year prior to winter crop planting, thus eliminating the earliest-germinating cohorts (Ahmed et al, 2022). Furthermore, late emerging C. bursa-pastoris individuals might exhibit reduced reproduction and survival due to winter crop competition.…”

A Synoptic Review of Plant Disease Epidemics and Outbreaks Published in 2021

“…This weed is known to be a host for pathogens that have been reported to infect annual crops, including fungi, oomycetes, bacteria, phytoplasmas, viruses, nematodes, and parasitic plants. In Canada it has been one of the 20 most prevalent weeds since annual surveys began in 1970 (Ahmed et al 2021).…”