Effects of Vegetation Disturbances on Insect Biological Control of Tansy Ragwort, Senecio Jacobaea

1993 ◽  
Vol 3 (4) ◽  
pp. 682-698 ◽  
Author(s):  
Peter B. McEvoy ◽  
Nathan T. Rudd
Keyword(s):  
Biological Control ◽  
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

Predator Interference with the Cinnabar Moth (Tyria jacobaeae) for the Biological Control of Tansy Ragwort (Senecio jacobaea)

2011 ◽  
Vol 4 (3) ◽  
pp. 332-340 ◽  
Author(s):  
Kimberly K. Crider
Keyword(s):  
Biological Control ◽  
Invasive Plant ◽  
Abiotic Factors ◽  
Biological Control Agents ◽  
Moth Population ◽  
Tyria Jacobaeae ◽  
Carpenter Ants ◽  
Ant Predation ◽  
Cinnabar Moth ◽  
Tansy Ragwort

AbstractQuantification of interference with biological control agents can provide support for anecdotal claims of success or failure of agent establishment and efficacy. This study was initiated because of observed predation of cinnabar moth larvae by carpenter ants when releasing larvae for the control of tansy ragwort, an invasive plant in Montana. Biotic and abiotic factors were compared among three sites with historically variable moth population establishment. Two experiments were developed to (1) observe and document insect activity, predation, or disappearance on tansy ragwort stems either protected or accessible to ants; and (2) quantify the effects of ant exclusion on herbivory of tansy ragwort. Site comparisons indicated that ant colony density was highest at the driest of three sites, and, interestingly, no ant colonies were detected at the site with higher observed numbers of moth larvae and adults and lower densities of tansy ragwort. Available substrate (logs and stumps) for ant colonization did not differ between the three sites. In the ant exclusion experiments, a larger number of larvae were missing on plants accessible to ants (63%) compared with plants where ants were excluded (39%) after 36 h. Direct observation of predation of larvae by carpenter ants accounted for 9% of missing larvae on stems accessible to ants. Larvae were able to consume 81% of original flowers or buds on ant-excluded stems, compared with 18% consumption on ant-accessible stems, suggesting that ant predation could limit the efficacy of cinnabar moth larvae. These results provide one of many possible explanations for the anecdotal observations of large, persistent populations of cinnabar moths in moist areas. This work emphasizes the importance of post-release observation and monitoring to detect and, ideally, quantify factors to support anecdotal perceptions regarding the fate and subsequent efficacy of insect biological-control agents.

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.

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

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.

scholarly journals The effects of agent hybridization on the efficacy of biological control of tansy ragwort at high elevations

2018 ◽  
Vol 12 (3) ◽  
pp. 470-481 ◽  
Author(s):  
Marianna Szűcs ◽  
Patricia E. Salerno ◽  
Brittany J. Teller ◽  
Urs Schaffner ◽  
Jeffrey L. Littlefield ◽  
...  
Keyword(s):  
Biological Control ◽  
High Elevations ◽  
Tansy Ragwort
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