Controlling Leafy Spurge with Grazing Animals

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.

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

Weeds ◽

10.2307/4040207 ◽

1956 ◽

Vol 4 (3) ◽

pp. 275 ◽

Cited By ~ 1

Author(s):

Duane Le Tourneau

Keyword(s):

Amino Acids ◽

Leafy Spurge ◽

Euphorbia Esula

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Polyamines, auxins and organogenesis in leafy spurge (Euphorbia esula L.)

Journal of Plant Physiology ◽

10.1016/s0176-1617(97)80237-4 ◽

1997 ◽

Vol 151 (5) ◽

pp. 603-609 ◽

Cited By ~ 7

Author(s):

David G. Davis

Keyword(s):

Leafy Spurge ◽

Euphorbia Esula

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Seasonal Photosynthesis and Partitioning of Nonstructural Carbohydrates in Leafy Spurge (Euphorbia esula)

Weed Science ◽

10.1614/ws-07-039 ◽

2007 ◽

Vol 55 (4) ◽

pp. 346-351 ◽

Cited By ~ 3

Author(s):

Russ W. Gesch ◽

Debra Palmquist ◽

James V. Anderson

Keyword(s):

Late Summer ◽

Leafy Spurge ◽

Adventitious Bud ◽

Adventitious Buds ◽

Continuous Increase ◽

Carbohydrate Partitioning ◽

Growing Seasons ◽

Autumn Leaf ◽

Carbohydrate Status ◽

New Strategies

Previous evidence indicates that changes in well-defined phases of dormancy in underground adventitious buds of leafy spurge in late summer and autumn are regulated by complex sensing and signaling pathways involving aboveground sugar signals. However, little information exists concerning seasonal photosynthesis and carbohydrate partitioning of leafy spurge, although such information would help to elucidate the involvement of sugar in controlling bud dormancy. An outdoor study was conducted over two growing seasons to determine and model seasonal patterns of photosynthesis and aboveground carbohydrate partitioning and their relationship to underground adventitious bud carbohydrate status. Photosynthesis and total nonstructural carbohydrate (TNC) content of aboveground tissues was greatest during vegetative growth. Photosynthesis gradually declined over the growing season, whereas TNC decreased sharply during flowering, followed by a gradual decline between midsummer and autumn. Leaf starch increased dramatically to midsummer before declining sharply throughout late summer and early autumn, whereas sucrose content responded inversely, indicating a mobilization of starch reserves and export of sugars to overwintering belowground sink tissues. Because newly formed underground adventitious buds showed a continuous increase in TNC from midsummer through autumn, export of sugars from aboveground tissues likely contributed to the increase in TNC. These results may facilitate new strategies for biological control of leafy spurge.

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Spectral characteristics of leafy spurge (Euphorbia esula) leaves and flower bracts

Weed Science ◽

10.1614/ws-03-132r ◽

2004 ◽

Vol 52 (4) ◽

pp. 492-497 ◽

Cited By ~ 17

Author(s):

E. Raymond Hunt ◽

James E. McMurtrey ◽

Amy E. Parker Williams ◽

Lawrence A. Corp

Keyword(s):

Remote Sensing ◽

High Performance ◽

Near Infrared ◽

Spectral Characteristics ◽

Leafy Spurge ◽

Hyperspectral Remote Sensing ◽

Total Carotenoids ◽

Physiological Basis ◽

Infrared Wavelengths ◽

Pigment Concentrations

Leafy spurge can be detected during flowering with either aerial photography or hyperspectral remote sensing because of the distinctive yellow-green color of the flower bracts. The spectral characteristics of flower bracts and leaves were compared with pigment concentrations to determine the physiological basis of the remote sensing signature. Compared with leaves of leafy spurge, flower bracts had lower reflectance at blue wavelengths (400 to 500 nm), greater reflectance at green, yellow, and orange wavelengths (525 to 650 nm), and approximately equal reflectances at 680 nm (red) and at near-infrared wavelengths (725 to 850 nm). Pigments from leaves and flower bracts were extracted in dimethyl sulfoxide, and the pigment concentrations were determined spectrophotometrically. Carotenoid pigments were identified using high-performance liquid chromatography. Flower bracts had 84% less chlorophylla, 82% less chlorophyllb, and 44% less total carotenoids than leaves, thus absorptance by the flower bracts should be less and the reflectance should be greater at blue and red wavelengths. The carotenoid to chlorophyll ratio of the flower bracts was approximately 1:1, explaining the hue of the flower bracts but not the value of reflectance. The primary carotenoids were lutein, β-carotene, and β-cryptoxanthin in a 3.7:1.5:1 ratio for flower bracts and in a 4.8:1.3:1 ratio for leaves, respectively. There was 10.2 μg g−1fresh weight of colorless phytofluene present in the flower bracts and none in the leaves. The fluorescence spectrum indicated high blue, red, and far-red emission for leaves compared with flower bracts. Fluorescent emissions from leaves may contribute to the higher apparent leaf reflectance in the blue and red wavelength regions. The spectral characteristics of leafy spurge are important for constructing a well-documented spectral library that could be used with hyperspectral remote sensing.

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Effect of Leafy Spurge (Euphorbia esula) Genotype on Feeding Damage and Reproduction of Aphthona spp.: Implications for Biological Weed Control

Biological Control ◽

10.1006/bcon.2001.0998 ◽

2002 ◽

Vol 23 (2) ◽

pp. 127-133 ◽

Cited By ~ 22

Author(s):

Rodney G. Lym ◽

Robert B. Carlson

Keyword(s):

Weed Control ◽

Leafy Spurge ◽

Euphorbia Esula ◽

Biological Weed Control ◽

Feeding Damage

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

Weed Technology ◽

10.1017/s0890037x0002981x ◽

1987 ◽

Vol 1 (4) ◽

pp. 314-318 ◽

Cited By ~ 49

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.

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Elaiosomes on Weed Seeds and the Potential for Myrmecochory in Naturalized Plants

Weed Science ◽

10.1017/s0043174500051584 ◽

1990 ◽

Vol 38 (6) ◽

pp. 615-619 ◽

Cited By ~ 27

Author(s):

Robert W. Pemberton ◽

Delilah W. Irving

Keyword(s):

United States ◽

The United States ◽

Leafy Spurge ◽

Spotted Knapweed ◽

Canada Thistle ◽

Weed Seeds ◽

Naturalized Plants ◽

Bull Thistle ◽

Diffuse Knapweed

Seeds of plants naturalized in the United States were examined for the presence of elaiosomes. Seeds of 47 species belonging to 13 families (Asteraceae, Boraginaceae, Dipsacaceae, Euphorbiaceae, Fabaceae, Fumariaceae, Lamiaceae, Liliaceae, Poaceae, Polygonaceae, Resedaceae, Rosaceae, and Solanaceae) were found to have elaiosomes, indicating that these species are probably mymecochorous, i.e., dispersed by ants. These include important rangeland weeds such as bull thistle, Canada thistle, musk thistle, diffuse knapweed, spotted knapweed, and leafy spurge. Myrmecochory in naturalized species may enhance their weediness in areas where they are established and assist their colonization of new and relatively closed communities.

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