scholarly journals The Distribution of Leafy Spurge (Euphorbia esula) and Other Weedy Euphorbia spp. in the United States

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 509-516 ◽  
Author(s):  
P. H. Dunn
Keyword(s):  
United States ◽  
Biological Control ◽  
The United States ◽  
Leafy Spurge ◽  
Economic Importance ◽  
Euphorbia Esula ◽  
Made In

A survey was made in the United States to determine the extent of the infestations of leafy spurge (Euphorbia esula L.) and other weeds of economic importance in the Euphorbiaceae. From introductions about 100 yr ago, leafy spurge is now found in 458 counties in 26 states from coast to coast. The infestations are out of control in some states, and biological control is mentioned as a possible solution to the problem.

Distribution of Yellow Starthistle (Centaurea solstitialis) and Russian Knapweed (Centaurea repens)

Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 315-327 ◽  
Author(s):  
Donald M. Maddox ◽  
Aubrey Mayfield ◽  
Noah H. Poritz
Keyword(s):  
United States ◽  
The United States ◽  
Economic Importance ◽  
Western United States ◽  
Centaurea Solstitialis ◽  
Yellow Starthistle ◽  
Russian Knapweed ◽  
Centaurea Repens ◽  
The World ◽  
Made In

The world distributions of yellow starthistle (Centaurea solstitialis L. ♯ CENSO) and Russian knapweed (Centaurea repens L. ♯ CENRE) are mapped based on information from world regional floras. A survey of weed specialists and herbaria was made in the United States, and the extent of the infestations and economic importance of these weeds was determined for the 48 contiguous states. Yellow starthistle currently occurs in 209 counties in 23 states and has apparently increased in abundance since 1970. Russian knapweed was reported in 412 counties in 21 states and does not seem to be spreading. Both of these weedy plant species are of greater economic importance in the western United States than in the east.

Distribution of Biological Control Agents of Leafy Spurge (Euphorbia esulaL.) in the United States: 1988–1996

1997 ◽  
Vol 10 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Richard W. Hansen ◽  
Robert D. Richard ◽  
Paul E. Parker ◽  
Lloyd E. Wendel
Keyword(s):  
United States ◽  
Biological Control ◽  
The United States ◽  
Leafy Spurge ◽  
Biological Control Agents

First Recovery of Oberea erythrocephala on the Leafy Spurge Complex in the United States

Weed Science ◽  
1986 ◽  
Vol 34 (3) ◽  
pp. 395-397 ◽  
Author(s):  
Norman E. Rees ◽  
Robert W. Pemberton ◽  
Antonio Rizza ◽  
Pasquale Pecora
Keyword(s):  
United States ◽  
The United States ◽  
Leafy Spurge ◽  
Euphorbia Esula

The beetle Oberea erythrocephala, whose larvae mine stems and roots of leafy spurge (Euphorbia esula L. # EPHES), was introduced into Oregon, Montana, and Wyoming between 1980 and 1984. Although it was not recovered in Oregon and Wyoming, it became established at two of three release sites in Montana and appears to be accepting leafy spurge plants at a fourth.

Assessing the role of generalist predators in the biological control of alfalfa weevil (Coleoptera: Curculionidae)

2017 ◽  
Vol 149 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Tatyana A. Rand
Keyword(s):  
United States ◽  
Biological Control ◽  
Experimental Work ◽  
United States Of America ◽  
Acyrthosiphon Pisum ◽  
The United States ◽  
Generalist Predators ◽  
Alfalfa Weevil ◽  
Exclusion Experiment ◽  
Predator Exclusion

AbstractAlfalfa weevil (Coleoptera:Curculionidae) is a major pest of alfalfa throughout the United States of America. Biological control research has disproportionately focussed on introduced parasitoids. Generalist predators may also be important, but experimental work evaluating their impacts is lacking. I combined a cross-site survey with a predator exclusion experiment to identify key predators, and test for impacts on weevil survival and plant defoliation levels in Montana and North Dakota, United States of America. Spiders (Araneae) dominated the complex, followed by Nabidae (Hemiptera) and Coccinellidae (Coleoptera). None of the dominant predators showed aggregative responses to weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) or pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) densities across 10 sites surveyed. However, weevil densities were positively correlated with both coccinellid and nabid densities across transects at the experimental site. Thus, predator groups traditionally associated with aphids can show strong aggregative numerical responses to alfalfa weevil larvae at smaller scales. Predator exclusion revealed no significant predator effects on larval survival or alfalfa damage. However, final densities of pea aphids were significantly higher in exclusion treatments relative to controls. The results suggest that even under conditions where predators exert significant pressure on aphids, they may still have minimal impacts on weevils. Additional experimental work is necessary to determine the broader potential of generalist predators as alfalfa weevil control agents.

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