THE BIOLOGY OF CANADIAN WEEDS.: 58. Galinsoga parviflora and G. quadriradiata (= G. ciliata).

Warwick, S. I.; Sweet, R. D.

doi:10.4141/cjps83-087

Cited by 31 publications

(44 citation statements)

References 2 publications

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“…Hairy galinsoga, the species named as most problematic and most risky by New England vegetable farmers, lacks dormancy in the soil 45 . Incorporate the cost of time and labor and crop quality along with reduced yield to better represent economic impact of weed management strategy for farmers .…”

Section: Farmer Beliefs Communication/research Recommendationsmentioning

confidence: 99%

Mental models of organic weed management: Comparison of New England US farmer and expert models

Jabbour

Zwickle

Gallandt

et al. 2013

Renew. Agric. Food Syst.

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Weeds are a major challenge for organic farmers, yet we know little about the factors influencing organic farmers' weed management decisions. We hypothesized that farmers and scientist 'experts' differ in fundamental areas of knowledge and perceptions regarding weeds and weed management. Moreover, these differences prevent effective communication, outreach programming and research prioritization. An expert mental model, constructed primarily from interviews with research scientists and extension professionals, revealed expert emphasis on knowledge of ecological weed management as crucial for successfully implementing such strategies. We interviewed 23 organic farmers in northern New England, yielding an aggregate farmer mental model to compare with the expert model. Farmers demonstrated knowledge of the major concepts discussed by experts, but differed in emphasis. Farmers placed less emphasis on ecological complexity than experts. One-third of farmers interviewed discussed the potential role of weeds as indicators of soil nutrient status, a concept of which experts were skeptical. Farmer beliefs about the weed seedbank highlighted potential misconceptions regarding seed persistence, with one-fourth of farmers focusing on the concept that seeds can live for an exceptionally long time in the soil, while experts focused on the concept of the seed half-life. Farmers emphasized the role of experience, both their own and that of other farmers, rather than knowledge derived from scientific research. Farmers considered yield and the cost of time and labor as equally at risk because of weeds, whereas experts predominantly discussed yield loss. During discussions of management, both farmers and experts most emphasized risks associated with cultivation and benefits associated with cover cropping. These results have prompted us, first, to develop new educational materials focused on weed seed longevity and management of the weed seedbank, and, second, to conduct regional focus groups with farmers who prioritize fertility management in their efforts to control weeds, especially manipulations of soil calcium and magnesium.

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Section: Farmer Beliefs Communication/research Recommendationsmentioning

confidence: 99%

Mental models of organic weed management: Comparison of New England US farmer and expert models

Jabbour

Zwickle

Gallandt

et al. 2013

Renew. Agric. Food Syst.

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show abstract

“…In later years, flushes occurred after cultivations, especially in April, but there was also sporadic emergence at other times and the seeds were relatively persistent. Warwick & Sweet (1983) concluded that since there is little or no dormancy, infestations can often be eliminated in 3-4 years. Some seeds of Galinsoga parviflora sown in August gave rise to seedlings in September and October and more began to appear in March.…”

Section: Emergence Mainly In Autumn: Seeds Persistentmentioning

confidence: 99%

Seed Persistence in Soil and Seasonal Emergence in Plant Species from Different Habitats

Roberts¹

1986

The Journal of Applied Ecology

129

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Applied Ecology. SUMMARY(1) The extent to which plants form a persistent seed bank and the time of year at which seedlings arise from it both have a bearing on the establishment of vegetation after disturbance. These attributes were determined for seventy dicotyledons from a range of habitats by mixing freshly-collected seeds with the top 7.5 cm of soil confined in cylinders sunk in the ground, cultivating three times yearly, and recording emergence for 5 years.(2) In about one-third of the species, few seeds persisted for longer than a year and most seedlings emerged in the autumn of sowing (Sherardia arvensis*, Galium mollugo) or early in the following spring (Chaerophyllum temulentum, Pimpinella saxifraga, Agrimonia eupatoria, Tragopogon pratensis).(3) The remaining species formed a persistent seed bank in cultivated soil from which seedlings arose in each year for which the experiments continued. Some exhibited a consistent pattern of emergence entirely (Odontites verna, Linum catharticum) or mainly (Brassica nigra, Silene dioica) in spring, while others (Hyoscyamus niger, Erodium cicutarium, Amaranthus retroflexus) emerged in late spring and summer. Emergence of Arenaria serpyllifolia, Cerastium glomeratum and Anthriscus caucalis was mainly in early autumn, while that of Legousia hybrid began in autumn and continued into spring.(4) Other species showed no pronounced pattern of emergence in successive years. Although there was often a tendency for most seedlings to emerge in spring or autumn, some appeared throughout the growing season with flushes following soil disturbance. Included in this group were Barbarea vulgaris, Coronopus didymus, Ballota nigra and Dipsacus sylvestris.(5) There were consistent differences between species in the extent of immediate emergence, seed survival in disturbed soil and in the seasonal pattern of emergence. Seeds of annual weeds of arable land were all relatively long-lived, but otherwise there appeared to be little relationship between seed persistence and habitat. The results provide indications of the potential for regeneration by different species from the seed bank after disturbance of a plant community and of the times of year at which it is likely to take place.

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“…Galinsoga species occupy fields, gardens, railways and ruderal sites and may also invade seminatural habitats such as forest paths, clearings and margins in woodlands (Tokarska-Guzik, 2003Chmura, 2004;Kabuce and Priede, 2010a;Trzcińska-Tacik et al, 2010). Galinsoga species pose a threat to crop production by competing with cultivated plants and also by acting as alternate hosts for many insects, viruses and nematodes that affect crop species (Warwick and Sweet, 1983). Because it is an aggressive weed, Galinsoga has attracted the interest of several researchers, including embryologists.…”

Section: Galinsoga Quadriradiatamentioning

confidence: 99%

Comparative Anatomy of Ovules in Galinsoga, Solidago and Ratibida (Asteraceae)

Kolczyk¹,

Stolarczyk²,

Płachno³

2015

Acta Biologica Cracoviensia S. Botanica

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Many Asteraceae species have been introduced into horticulture as ornamental or interesting exotic plants. Some of them, including Solidago and Galinsoga, are now aggressive weeds; others such as Ratibida are not. Special modifications of the ovule tissue and the occurrence of nutritive tissue have been described in several Asteraceae species, including invasive Taraxacum species. This study examined whether such modifications might also occur in other genera. We found that the three genera examined - Galinsoga (G. quadriradiata), Solidago (S. canadensis, S. rigida, S. gigantea) and Ratibida (R. pinnata) - differed in their nutritive tissue structure. According to changes in the integument, we identified three types of ovules in Asteraceae: “Taraxacum” type (recorded in Taraxacum, Bellis, Solidago, Chondrilla), with well-developed nutritive tissue having very swollen cell walls of spongy structure; “Galinsoga” type (in Galinsoga), in which the nutritive tissue cells have more cyto-plasm and thicker cell walls than the other integument parenchyma cells, and in which the most prominent character of the nutritive tissue cells is well-developed rough ER; and “Ratibida” type (in Ratibida), in which the nutritive tissue is only slightly developed and consists of large highly vacuolated cells. Our study and future investigations of ovule structure may be useful in phylogenetic analyses.

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THE BIOLOGY OF CANADIAN WEEDS.: 58. Galinsoga parviflora and G. quadriradiata (= G. ciliata).

Cited by 31 publications

References 2 publications

Mental models of organic weed management: Comparison of New England US farmer and expert models

Mental models of organic weed management: Comparison of New England US farmer and expert models

Seed Persistence in Soil and Seasonal Emergence in Plant Species from Different Habitats

Comparative Anatomy of Ovules in Galinsoga, Solidago and Ratibida (Asteraceae)

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