Pyrrolizidine alkaloids: their occurrence in honey from tansy ragwort (Senecio jacobaea L.)

Science ◽  
1977 ◽  
Vol 195 (4277) ◽  
pp. 497-499 ◽  
Author(s):  
M. Deinzer ◽  
P. Thomson ◽  
D. Burgett ◽  
D. Isaacson
Keyword(s):  
Pyrrolizidine Alkaloids ◽  
Senecio Jacobaea ◽  
Tansy Ragwort

The biology of Canadian weeds.: 96. Senecio jacobaea L.

1991 ◽  
Vol 71 (1) ◽  
pp. 127-140 ◽  
Author(s):  
John F. Bain
Keyword(s):  
Biological Control ◽  
Pyrrolizidine Alkaloids ◽  
Biological Control Agent ◽  
Vegetative Reproduction ◽  
Control Agent ◽  
Effective Control ◽  
Senecio Jacobaea ◽  
Eastern Canada ◽  
Tyria Jacobaeae ◽  
Tansy Ragwort

Senecio jacobaea L. (tansy ragwort) is a roadside and pasture weed which was introduced into Canada in the 1850s. It is established in cool, wet areas, most commonly on the east and west coasts. The species is important economically because the presence of pyrrolizidine alkaloids in the foliage makes it toxic and the poisoning of livestock has resulted. Individuals produce dimorphic achenes which possess different dormancy and dispersal characters and are therefore able to establish in a wider range of habitats. Vegetative reproduction is common especially after damage to the plant. Control of the weed is achieved either through the application of hormone-like herbicides or by biological means. The establishment of the biological control agent, cinnabar moth (Tyria jacobaeae L.), in populations has resulted in defoliation of individuals but has not resulted in effective control of the weed, except in eastern Canada. Key words: Tansy ragwort, Senecio jacobaea, biological control, pyrrolizidine alkaloids

Herbicides compromise biological control of ragwort

2002 ◽  
pp. 147-152
Author(s):  
K. Betteridge ◽  
D. Costall
Keyword(s):  
Biological Control ◽  
Pyrrolizidine Alkaloids ◽  
Animal Health ◽  
Flea Beetle ◽  
Dairy Farm ◽  
Senecio Jacobaea ◽  
Longitarsus Jacobaeae ◽  
High Ester ◽  
Low Levels

In spite of ragwort flea beetle (RFB) being present on a Dannevirke dairy farm, pastures were sprayed each winter to reduce ragwort density and limit the risk of ragwort poisoning of stock. The trial on this farm from June 1999 - October 2001, aimed to determine whether herbicide (H) impacted on RFB and how H and RFB each impacted on ragwort growth and persistence. RFBfree areas were created by spraying with insecticide (I). Effects of ragwort on animal health are also reported. High ester 2,4-D (H) boom-sprayed once only, in June 1999, killed most ragwort plants and reduced RFB larvae densities to low levels before the plants died. Once new ragwort established in treatment H, the plants became infested with RFB larvae. RFB larvae were suppressed by I resulting in ragwort density declining more slowly than in treatments where RFB were not suppressed. Insecticide treatments were stopped after 15 months and, at 24 months, ragwort could not be found within the trial area. Ragwort control was attributed to the cessation of herbicide spraying allowing the RFB population to reach a sufficient density to kill both small and large ragwort plants. Sub-clinical ragwort poisoning was found in livers of culled cows that had grazed on ragwort-dense pastures. Keywords: animal health, biological control, Longitarsus jacobaeae, pyrrolizidine alkaloids, ragwort, ragwort flea beetle, Senecio jacobaea

Germination and Dry-Matter Accumulation in Dimorphic Achenes of Tansy Ragwort (Senecio jacobaea)

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 539-545 ◽  
Author(s):  
Ann L. Baker-Kratz ◽  
James D. Maguire
Keyword(s):  
Dry Matter ◽  
Dry Matter Accumulation ◽  
Senecio Jacobaea ◽  
Percentage Germination ◽  
Physiological Maturity ◽  
Central Disk ◽  
Tansy Ragwort

Mature achenes from tansy ragwort (Senecio jacobaea L. ♯3 SENJA) capitula borne on lower branches had greater average dry weights and higher percentage germination than those closer to the apex, but these higher averages were obtained because more achenes in these samples were filled. Physiological maturity was attained in ray achenes 21 days past flowering (DPF), 24 DPF in peripheral disk achenes, and 27 DPF in central disk achenes. Maximum germination occurred at 18 DPF in ray and peripheral disk achenes and at 21 DPF in central disk achenes. Neither achene type was shown to have innate dormancy. Disk and ray achenes germinated most rapidly at alternating temperatures of 30/20 C.

EFFECTS OF HERBICIDE RATES AND TIME OF APPLICATION ON THE CONTROL OF TANSY RAGWORT IN PASTURES

1976 ◽  
Vol 56 (3) ◽  
pp. 605-610 ◽  
Author(s):  
W. N. BLACK
Keyword(s):  
Acetic Acid ◽  
Propionic Acid ◽  
Active Ingredient ◽  
White Clover ◽  
Senecio Jacobaea ◽  
Time Of Application ◽  
Trifolium Repens L ◽  
Dichlorophenoxy Acetic Acid ◽  
Acetic Acids ◽  
Tansy Ragwort

The ester of 2,4-D [(2,4-dichlorophenoxy) acetic acid] at 1.1 kg active ingredient (a.i.)/ha failed to control tansy ragwort (Senecio jacobaea L.) in the late-rosette, bud, and flowering stages of development. Sprays of 2,4-D ester at 2.2 kg/ha were more effective than when applied at 1.1 kg/ha, but repeated treatments were necessary for optimum tansy ragwort control. Comparative dosage levels of the esters of 2,4-D and of 2,4-DB [4-(2,4-dichlorophenoxy) butyric acid] showed 2,4-D giving better control of tansy ragwort when applied at equivalent rates. Control of relatively immature tansy ragwort plants with 2,4-D was not significantly different at the 1.1, 2.2, and 4.5 kg/ha levels, but injury to grasses and white clover (Trifolium repens L.) increased at the higher rates. The ester of 2,4-DB at 2.2 and 4.5 kg/ha effectively controlled seedling and early-rosette tansy ragwort plants only. The quantity of water applied as a spray was critical since the frond-type leaves which fold over one another prevented thorough wetting of the entire foliage with spray volumes under 275 liters/ha. Data obtained over a 4-yr period showed that CMPP (±) 2-[(4-chloro-1-tolyl) oxy) propionic acid], CP 1815 (chlorinated benzoic and cresoxy-acetic acids), 2,3,6-TBA (dimethylamine salt of 2,3,6-trichlorobenzoic acid), 2,4-D acid [weedone 638, emulsifiable concentrate-(2,4-dichlorophenoxy) acetic acid], and fenoprop [2-(2,4,5-trichlorophenoxy) propionic acid] were as effective as the ester of 2,4-D for tansy ragwort control but caused more injury to components of the sward.

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