ABSTRACT
The title of this chapter — Can Feral Radishes Become Weeds? — is phrased as a question for three reasons. First, the literature on this topic is incomplete and we expect that further investigations will help elucidate the answer to this question. Second, many feral populations of Raphanus sativus have resulted from hybrids between the crop and a closely related weed, R. raphanistrum, and it is not known whether this external “trigger” is essential for feral populations to become weedy. Third, the answer depends on one’s definition of a weed. Inconsistent use of this term can lead to confusion about the weed status of feral radishes. Agricultural scientists define weeds as plants that reduce the productivity of crops, other managed plantations (e.g., vineyards, orchards, planted pine forests), or pastures and range land. A broader definition of weeds includes any plant that causes economic or environmental harm — for example, in agriculture, lawns, recreational areas, wetlands, and other natural areas. Weedy plants that displace native vegetation often are referred to as invasives, and economic losses due to invasive plants can be substantial (48). Another category of weeds, which we will not employ here, includes species that occupy disturbed, ruderal habitats without necessarily causing economic or environmental harm.
