scholarly journals Utilization of Leafy Spurge (Euphorbia esula) by Sheep

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 348-352 ◽  
Author(s):  
Barbara K. Landgraf ◽  
Peter K. Fay ◽  
Kris M. Havstad
Keyword(s):  
Biological Control ◽  
Body Weight ◽  
Weight Gain ◽  
Biological Control Agent ◽  
Leafy Spurge ◽  
Control Agent ◽  
Significant Loss ◽  
Euphorbia Esula ◽  
Steady Increase ◽  
Grazing Behavior

The forage selection and grazing behavior of sheep in leafy spurge (Euphorbia esula L. ♯3 EPHES)-infested pastures was examined in a 3-month grazing study conducted during the summer, 1981. No definite preference for or avoidance of leafy spurge was detected. An initial 1- to 3-week avoidance was observed, followed by a steady increase in leafy spurge consumption. A maximum intake of 40 to 50% of the diet per animal was observed. Weight gain by ewes in pastures infested with leafy spurge was not significantly different from weight gain by ewes in pastures free of leafy spurge. Results from these studies indicate that leafy spurge may be classified as a forage for sheep. Sheep will consume a significant amount of vegetation while suffering neither harmful internal effects nor a significant loss of body weight. Sheep can be considered an effective biological control agent for leafy spurge.

AnAlternariasp. on Leafy Spurge (Euphorbia esula)

Weed Science ◽  
1983 ◽  
Vol 31 (1) ◽  
pp. 86-88 ◽  
Author(s):  
Joseph M. Krupinsky ◽  
Russell J. Lorenz
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Field Studies ◽  
Leafy Spurge ◽  
Control Agent ◽  
Euphorbia Esula ◽  
Cultural Characteristics ◽  
Representative Strain

In 1979 and 1980, isolates ofAlternariawere obtained from diseased leafy spurge (Euphorbia esulaL.) plants. The pathogenicity of anAlternariasp. towards leafy spurge was demonstrated in glasshouse and limited field studies, and theAlternariais considered to be a potential biological - control agent for leafy spurge. The pathogenicity and cultural characteristics of the fungus suggest its classification asA. tenuissimaf. sp.euphorbiae,with isolate Krupinsky 80-3547ss4 (= E. G. Simmons 35-079) as a representative strain.

Population Dynamics and Impacts of the Red-Headed Leafy Spurge Stem Borer on Leafy Spurge (Euphorbia esula)

2011 ◽  
Vol 4 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Robert A. Progar ◽  
George Markin ◽  
Joseph Milan ◽  
Tom Barbouletos ◽  
Matthew J. Rinella
Keyword(s):  
Biological Control ◽  
Invasive Plant ◽  
Biological Control Agent ◽  
Stem Borer ◽  
Leafy Spurge ◽  
Control Agent ◽  
Euphorbia Esula ◽  
Western United States ◽  
Large Populations ◽  
And Control

AbstractWe evaluated the efficacy of the biological control agent, red-headed leafy spurge stem borer, against the nonnative invasive plant leafy spurge. Our three treatments were release of the biological control agent into uncaged plots, release of the biological control agent into plots caged to prevent agent escape, and control plots caged to prevent agent entry. These treatments were replicated three times at six sites in the western United States. We measured leafy spurge biomass for 1 or 2 yr following release. We also measured the percentage of leafy spurge stems showing evidence of red-headed leafy spurge stem borer oviposition for either 1 or 2 yr following agent release, depending on the site. Red-headed leafy spurge stem borer did not demonstrably reduce leafy spurge biomass in our study. Moreover, compared to the release year, evidence of red-headed leafy spurge stem borer oviposition declined with time, suggesting the agent population was diminishing. This suggests the agent is incapable of building large populations capable of controlling leafy spurge at the sites we studied. However, after being released, populations of biological control agents sometimes go through long lag phases and then begin rapid population increases, so we cannot completely dismiss the possibility that red-headed leafy spurge stem borer might become effective given more time.

scholarly journals Control of Leafy Spurge (Euphorbia esula) in Nebraska with the Spurge Hawkmoth (Hyles euphorbiae)

Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 235-240 ◽  
Author(s):  
J. R. Forwood ◽  
M. K. McCarty
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Soil Surface ◽  
Leafy Spurge ◽  
Control Agent ◽  
Euphorbia Esula ◽  
Two Generations ◽  
Hyles Euphorbiae

The feasibility of using the spurge hawkmoth (Hyles euphorbiaeL., Lepidoptera: Sphingidae), as a biological control agent on leafy spurge (Euphorbia esulaL.) was evaluated. Studies relating adult hawkmoth emergence from the pupal stage and spring growth of leafy spurge plants showed that the plants would provide food and oviposition sites for the insect. Two generations of the insect may occur each year. Winter temperatures at approximately 2.5 cm below the soil surface or in the litter would result in some mortality of hawkmoth pupae. Pupal release programs indicated that protection from insect and rodent predators was necessary for adult emergence to occur. Predator determination using32P indicated two specimens ofCalosoma calidumFab. and two specimens ofFormica subsericeaSay as possible predators. Predator determination using pitfall traps showed that several species listed by Canadian researchers as predators were present in leafy spurge stands in Nebraska. At this time it appears the spurge hawkmoth will not become a valuable biological control agent for leafy spurge in Nebraska.

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.

Integrating Flea Beetles (Aphthonaspp.) with Herbicide and Grasses for Leafy Spurge (Euphorbia Esula) Management

2008 ◽  
Vol 22 (3) ◽  
pp. 523-529 ◽  
Author(s):  
Ankush Joshi
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Leafy Spurge ◽  
Control Agent ◽  
Euphorbia Esula ◽  
Grass Species ◽  
Stem Density ◽  
Biological Control Agents ◽  
Single Application ◽  
Sheyenne National Grassland

Most management tactics used against leafy spurge are not economical, practical, or efficacious when used alone. Combinations of the biological control agent,Aphthonabeetles, the herbicide imazapic (105 g/ha), and interseeded native grass species were evaluated for leafy spurge management at two sites: Sheyenne National Grassland and Ekre Grassland Preserve in North Dakota during 2001 to 2005. At the Sheyenne site, over a 5-yr study period, leafy spurge was reestablishing its stem density after a single application of imazapic, but stand suppression was maintained to < 11 stems/m2when management combined imazapic withAphthonaor interseeding of native grasses.Aphthonabeetles established at the Sheyenne site, but declined as leafy spurge density decreased. However, the remainingAphthonapopulation continued to suppress leafy spurge density. Leafy spurge stem control was successfully maintained for 3 yr byAphthonaand grass competition without repetition of the imazapic treatment. Leafy spurge root dry weights were reduced by 66% (< 111g/m2) in the insect plots during this period. At the Ekre site, similar results were observed for the first 3 yr. However, in the fourth yr, a failure of biological control agents to establish resulted in the resurgence of leafy spurge. During this study, lowerAphthonaemergence was observed in imazapic-treated plots, possibly due to reduced leafy spurge density.

Microsatellite isolation from the gall midge Spurgia capitigena (Diptera: Cecidomyiidae), a biological control agent of leafy spurge

2004 ◽  
Vol 4 (4) ◽  
pp. 605-607 ◽  
Author(s):  
CASANDRA J. LLOYD ◽  
ANDREW P. NORTON ◽  
RUTH A. HUFBAUER ◽  
STEVEN M. BOGDANOWICZ ◽  
SCOTT J. NISSEN
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Gall Midge ◽  
Leafy Spurge ◽  
Control Agent ◽  
Microsatellite Isolation
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