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

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.

Weed Science ◽  
1983 ◽  
Vol 31 (1) ◽  
pp. 86-88 ◽  
Author(s):  
Joseph M. Krupinsky ◽  
Russell J. Lorenz

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.


2011 ◽  
Vol 4 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Robert A. Progar ◽  
George Markin ◽  
Joseph Milan ◽  
Tom Barbouletos ◽  
Matthew J. Rinella

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.


Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 348-352 ◽  
Author(s):  
Barbara K. Landgraf ◽  
Peter K. Fay ◽  
Kris M. Havstad

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.


Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 235-240 ◽  
Author(s):  
J. R. Forwood ◽  
M. K. McCarty

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.


2008 ◽  
Vol 22 (3) ◽  
pp. 523-529 ◽  
Author(s):  
Ankush Joshi

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.


Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Angelica M. Reddy ◽  
Paul D. Pratt ◽  
Brenda J. Grewell ◽  
Nathan E. Harms ◽  
Ximena Cibils-Stewart ◽  
...  

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.


2004 ◽  
Vol 4 (4) ◽  
pp. 605-607 ◽  
Author(s):  
CASANDRA J. LLOYD ◽  
ANDREW P. NORTON ◽  
RUTH A. HUFBAUER ◽  
STEVEN M. BOGDANOWICZ ◽  
SCOTT J. NISSEN

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