THE BIOLOGY OF CANADIAN WEEDS. 39 Euphorbia esula L.

1980 ◽  
Vol 60 (2) ◽  
pp. 651-663 ◽  
Author(s):  
K.F. BEST ◽  
G.G. BOWES ◽  
A.G. THOMAS ◽  
M.G. MAW
Keyword(s):  
Introduced Species ◽  
Leafy Spurge ◽  
Biological Data ◽  
Euphorbia Esula ◽  
Native Plant ◽  
Ecological Amplitude ◽  
Plant Associations ◽  
Prairie Provinces

Biological data are summarized for Euphorbia esula L. (leafy spurge). The introduced species from Europe is found throughout Canada and is particularly prevalent in cultivated fields and rangelands of the Prairie Provinces. It has a broad ecological amplitude and is found growing in different native plant associations. Several herbicides are available for the control of E. esula.

scholarly journals Feeding Impacts of a Leafy Spurge (Euphorbia esula) Biological Control Agent on a Native Plant, Euphorbia robusta

2008 ◽  
Vol 1 (1) ◽  
pp. 26-30 ◽  
Author(s):  
John L. Baker ◽  
Nancy A. P. Webber
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Canopy Cover ◽  
Ground Cover ◽  
Leafy Spurge ◽  
Control Agent ◽  
Euphorbia Esula ◽  
Native Plant ◽  
Feeding Damage ◽  
Aphthona Nigriscutis

AbstractThe biological control agent Aphthona nigriscutis Foudras (Chrysomelidae) established in Fremont County, WY since 1992 on leafy spurge was released into a mixed stand a native plant Euphorbia robusta Engelm. During host range testing, E. robusta was a likely host for A. nigriscutis under laboratory conditions. In 1999, A. nigriscutis was observed feeding on both E. esula and 31 of 36 E. robusta plants present on about 2 ha (5 ac) where the visually estimated E. esula canopy cover was 50%. By August 2001, E. esula cover had declined to less than 5% and E. robusta plants had increased to 450 plants with 26 (5.8%) showing feeding damage. In 2006 Euphorbia esula ground cover was 2% and of 598 E. robusta plants originally marked, 391 could be located and four of these had damage consistent with A. nigriscutis feeding. For the 8-yr period, E. esula ground cover was inversely correlated to E. robusta density and positively correlated to A. nigriscutis feeding damage on E. robusta. This study shows that while also acceptable to A. nigriscutis in the field, feeding on E. robusta declined with declining densities of the target weed while E. robusta population densities increased. It seems that some risk in this regard is acceptable in light of the damage from the target weed and the generally high level of selectivity provided by biological control agents.

scholarly journals Release of Postsenescent Dormancy in Leafy Spurge (Euphorbia esula) by Chilling

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 784-786 ◽  
Author(s):  
Stephen J. Harvey ◽  
Robert M. Nowierski
Keyword(s):  
Growth Rate ◽  
North America ◽  
Growth And Development ◽  
Leafy Spurge ◽  
Climatic Conditions ◽  
Euphorbia Esula ◽  
Flower Buds ◽  
Significant Growth ◽  
Number Of Stems

The growth and development of leafy spurge (Euphorbia esulaL. #3EPHES) collected during postsenescent dormancy and grown in the greenhouse was increasingly stimulated by chilling treatments longer than 14 days duration at 0 to 6 C. Production of stems with flower buds, primary flowers, and secondary flowers was greater in plants chilled for 42 days or more. The effects of chilling on total number of stems, number of strictly vegetative stems, or number of stems with vegetative branching were not significant. The height of the tallest stem per pot was influenced by chilling longer than 42 days. Growth rate also increased as a function of chilling duration. Based on our findings, we believe that there is little possibility that any significant growth can occur in the postsenescent period because of the prevailing climatic conditions found in areas of leafy spurge distribution in North America.

A Note on the Sugars and Amino Acids of Leafy Spurge, Euphorbia esula

Weeds ◽  
1956 ◽  
Vol 4 (3) ◽  
pp. 275 ◽  
Author(s):  
Duane Le Tourneau
Keyword(s):  
Amino Acids ◽  
Leafy Spurge ◽  
Euphorbia Esula

Cattle Foraging Behavior in Leafy Spurge (Euphorbia esula)-Infested Rangeland

1987 ◽  
Vol 1 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Rodney G. Lym ◽  
Donald R. Kirby
Keyword(s):  
Warm Season ◽  
Economic Loss ◽  
Leafy Spurge ◽  
High Density ◽  
Euphorbia Esula ◽  
Low Density ◽  
Forage Production ◽  
Grazing Season ◽  
Grazing Cattle ◽  
Early Fall

Leafy spurge causes economic loss by reducing both herbage production and use. Herbage use by grazing cattle in various densities of leafy spurge (Euphorbia esulaL. #3EPHES) was evaluated over a 3-yr period in North Dakota. Forage production and disappearance were estimated in four density classes of leafy spurge. Use of cool- and warm-season graminoids, forbs, and leafy spurge was estimated during the middle and the end of each grazing season. Cattle used 20 and 2% of the herbage in the zero and low density infestations, respectively, by mid-season. Moderate and high density infestations were avoided until the milky latex in leafy spurge disappeared in early fall, and herbage availability in zero and low density infestations declined. Herbage use in moderate and high density infestations increased to an average of 46% by the end of the grazing season compared to 61% in zero and low density infestations. An annual herbage loss of at least 35% occurred in pasture infested with 50% density or more of leafy spurge.

Change in Leafy Spurge (Euphorbia esula) Density and Soil Seedbank Composition 10 Years following Release of Aphthona spp. Biological Control Agents

2013 ◽  
Vol 6 (1) ◽  
pp. 147-160 ◽  
Author(s):  
Cassandra M. Setter ◽  
Rodney G. Lym
Keyword(s):  
Native Species ◽  
Kentucky Bluegrass ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Stem Density ◽  
Ecological Sites ◽  
Western North Dakota ◽  
Soil Seedbank ◽  
Weedy Species ◽  
Native Species Richness

AbstractFlea beetles (Aphthona spp.) were released in the Little Missouri National Grasslands (LMNG) in western North Dakota in 1999 to control leafy spurge. The changes in leafy spurge density and soil seedbank composition were evaluated on two ecological sites 10 yr (2009) after Aphthona spp. release to monitor the effectiveness of the insects on weed control and the associated changes in plant communities. In 2009, leafy spurge stem density averaged 2 and 9 stems m−2 (0.19 to 0.84 ft−2) in the loamy overflow and loamy sites, respectively, compared with 110 and 78 stems m−2, respectively, in 1999. Leafy spurge constituted nearly 67% of the loamy overflow seedbank in 1999, compared with 2% in 2009. In the loamy seedbank, the weed represented nearly 70% in 1999, compared with approximately 15% in 2009. As leafy spurge abundance was reduced, native species richness and seed count increased 10 yr after Aphthona spp. release. Late seral species represented 17% of the loamy overflow seedbank in 2009, an increase from 5% in 1999. However, Kentucky bluegrass, a nontarget weedy species, increased more than 250% in the loamy overflow seedbank. Late seral species were 38% of the loamy seedbank in 2009, compared with 13% in 1999. The number of native species increased from 31 in 1999 to 39 in 2009 in the loamy overflow seedbank, but only changed from 32 to 34 species in the loamy site during the same period. The reestablishment of native species has been slow, but seedbank analysis indicates the number and type of species found before the leafy spurge infestation have increased. Planting native species in selected areas may have reduced the lag time in these species return to the seedbank and reduced invasion from other nondesirable species, such as Kentucky bluegrass.

Cytogenetic studies of leafy spurge, Euphorbia esula, and its allies (Euphorbiaceae)

1988 ◽  
Vol 66 (11) ◽  
pp. 2247-2257 ◽  
Author(s):  
A. E. Stahevitch ◽  
C. W. Crompton ◽  
W. A. Wojtas
Keyword(s):  
Seed Germination ◽  
Chromosome Number ◽  
Natural Populations ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Meiotic Abnormalities ◽  
Stability Studies ◽  
Polymorphic Species ◽  
Cytogenetic Studies ◽  
Euphorbia Cyparissias

Cytological and cytogenetic studies were carried out on populations of leafy spurge (Euphorbia esula L. s.l.) and its allies primarily from North America but also from Europe. Chromosome numbers were determined for 126 samples of E. esula, 11 of E. cyparissias L., 1 of the hybrid (E. ×pseudoesula Schur) between these two species, and 1 of E. agraria Bieb. All plants of E. esula were hexaploid. Of the total, 125 leafy spurge accessions had a chromosome number of n = 30; 1 of n = 25++. Very few meiotic abnormalities were observed. Euphorbia cyparissias was primarily tetraploid (n = 20), although occasional diploids (n = 10) were encountered. Tetraploids were fertile; diploids were sterile. The hybrid between the two foregoing species had a chromosome number of n = 25, indicating that the E. cyparissias parent was a tetraploid; meiosis in the hybrid was abnormal. Euphorbia agraria was found to have a gametic number of n = 20, which is the first chromosome number determination for this species; meiosis was normal. Artificial crosses were made successfully between 31 accessions of leafy spurge. Seed germination of the F1 progeny slightly exceeded that reported for natural populations, and meiosis was normal. Pollen stability studies were carried out on herbarium material. Stainability was 100% for most of the samples studied. Extensive pollen size polymorphism was found. It is suggested that this phenomenon supports the hypothesis that E. esula is of allopolyploid origin. No cytological or cytogenetic basis was found for considering the leafy spurge accessions examined in this study as other than as a single, albeit somewhat polymorphic, species.

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