Influence of spotted knapweed (Centaurea maculosa) management treatments on arbuscular mycorrhizae and soil aggregation

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 172-177 ◽  
Author(s):  
E. R. Lutgen ◽  
M. C. Rillig
Keyword(s):  
Soil Quality ◽  
Pacific Northwest ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Aggregate Stability ◽  
The United States ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
Negative Effects ◽  
Hyphal Length

Spotted knapweed is an invasive mycorrhizal weed prevalent in the Pacific Northwest of the United States. Little is known about the effects of spotted knapweed or its management methods on soil quality and soil structure. This study compared soils from spotted knapweed–infested areas with areas where spotted knapweed is being managed using several herbicides and mechanical treatments. We measured concentrations of glomalin, a glycoprotein produced by arbuscular mycorrhizal fungi (AMF), that is correlated with soil aggregate stability, AMF hyphal length, and percent water-stable aggregates (WSA) in soils from managed and unmanaged areas. Areas with high knapweed density (unmanaged areas) generally had lower glomalin concentrations and AMF hyphal lengths compared with areas receiving chemical and combined mechanical–chemical management treatments. Total glomalin was significantly negatively correlated with percent knapweed cover. However, WSA was high (70 to 80%) in soils from all management treatments and was not affected by knapweed cover. Our results suggest that spotted knapweed does not have negative effects on soil quality from our study site, likely because of the high aggregate stability of the soils in the area. However, Centaurea maculosa may have negative effects on soil quality in soils with lower aggregate stability.

Distribution of Urophora affinis and U. quadrifasciata, Two Flies Introduced for Biological Control of Spotted Knapweed (Centaurea maculosa) in Montana

Weed Science ◽  
1987 ◽  
Vol 35 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Jim M. Story ◽  
Robert M. Nowierski ◽  
Keith W. Boggs
Keyword(s):  
United States ◽  
Biological Control ◽  
North America ◽  
Positive Relationship ◽  
The United States ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
Seed Head ◽  
Strong Positive Relationship ◽  
Southeasterly Direction

A survey was conducted at 88 sites in Montana in 1984 and 1985 to determine the distribution of Urophora affinis Frauenfeld and U. quadrifasciata (Meigen), two seed head flies released on spotted knapweed (Centaurea maculosa Lam. # CENMA) in North America. U. affinis, released in Montana during 1973 to 1977, was found at 40 of the 88 sites. The fly was concentrated within a short radius (about 5 to 8 km) of release sites, even at sites having well-established populations. U. quadrifasciata, released in British Columbia in 1972, but not in the United States, was found at 84 sites. The data suggest that the fly entered the state in the northwest corner and dispersed in a southeasterly direction. There was a strong positive relationship between mean number of galls per seed head and percent infestation for both fly species.

METZNERIA PAUCIPUNCTELLA ZELLER (LEPIDOPTERA: GELECHIIDAE), A MOTH INTRODUCED AGAINST SPOTTED KNAPWEED: ITS FEEDING STRATEGY AND IMPACT ON TWO INTRODUCED UROPHORA SPP. (DIPTERA: TEPHRITIDAE)

1991 ◽  
Vol 123 (5) ◽  
pp. 1001-1007 ◽  
Author(s):  
J.M. Story ◽  
K.W. Boggs ◽  
W.R. Good ◽  
P. Harris ◽  
R.M. Nowierski
Keyword(s):  
Biological Control ◽  
Seed Dispersal ◽  
Pacific Northwest ◽  
Biocontrol Agent ◽  
Feeding Strategy ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
Seed Head ◽  
The Pacific ◽  
Normal Seed

AbstractMetzneria paucipunctella Zeller is a seed head moth introduced for biological control of spotted knapweed, Centaurea maculosa Lamarck, in the Pacific Northwest. A cage study was conducted in Montana in 1987 and 1988 to assess the feeding strategy of the M. paucipunctella larva and its impact on two seed head flies, Urophora spp., also introduced on spotted knapweed. Each moth larva destroyed an average of 8.13 knapweed seeds. Most of the seeds were destroyed prior to seed dispersal in early September but the remaining seeds were attacked in the spring of the following year. Each larva tied an average of 7.0 seeds with silk webbing which allowed for feeding long after normal seed dispersal. Seed survival in cages containing both the moth and the two fly species (4.71 seeds per head) was significantly less than in fly-only cages (9.75 seeds per head). The moth larvae caused extensive mortality to the two Urophora species, especially during the spring months. Moth-caused mortality to U. affinis larvae increased from 19% during June through October to 67% in May of the following year. Mortality to U. quadrifasciata also occurred but did not increase significantly in the spring. Data from 10 field sites showed very little association between M. paucipunctella and the two Urophora species which suggests that the unnatural conditions associated with the cages did not increase the incidence of joint moth and fly attack to individual seed heads. The moth is a valuable biocontrol agent as it is contributing significantly to the overall consumer pressure on spotted knapweed seed heads.

FIRST REPORT OF THE DISPERSAL INTO MONTANA OF UROPHORA QUADRIFASCIATA (DIPTERA: TEPHRITIDAE), A FLY RELEASED IN CANADA FOR BIOLOGICAL CONTROL OF SPOTTED AND DIFFUSE KNAPWEED

1985 ◽  
Vol 117 (8) ◽  
pp. 1061-1062 ◽  
Author(s):  
Jim M. Story
Keyword(s):  
Biological Control ◽  
British Columbia ◽  
The United States ◽  
Flower Head ◽  
The Other ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
European Origin ◽  
Mature Flower ◽  
Diffuse Knapweed

Two tephritid flies of European origin have been introduced into North America for biological control of spotted knapweed, Centaurea maculosa Lam., and diffuse knapweed, C. diffusa Lam. One, Urophora affinis Frauenfeld, was released in British Columbia in 1970 and in 5 states, including Montana, in 1973 (Hanis 1980a; Maddox 1979; Story and Anderson 1978). The other, Urophora quadrifasciata (Meigen), was introduced at Ned's Creek, British Columbia but was not released in the United States. The larvae of both flies induce galls (1 larva/gall) in immature knapweed flower heads and thus reduce seed production. Galls of Urophora affinis occur in the flower-head receptacle whereas galls of U. quadrifasciata are in the ovary wall. In contrast with U. affinis, which has only a partial second generation, U. quadrifasciata normally has 2 complete generations per year, induces thinner galls, and attacks more-mature flower heads than does U. affinis (Harris 1980a).

Arbuscular mycorrhizae, glomalin, and soil aggregation

2004 ◽  
Vol 84 (4) ◽  
pp. 355-363 ◽  
Author(s):  
Matthias C. Rillig
Keyword(s):  
Soil Quality ◽  
Mycorrhizal Fungi ◽  
Soil Structure ◽  
Arbuscular Mycorrhizae ◽  
Management Strategies ◽  
Arbuscular Mycorrhizal ◽  
Great Promise ◽  
Soil C ◽  
Protein Pool ◽  
Soil Protein

Arbuscular mycorrhizae are important factors of soil quality through their effects on host plant physiology, soil ecological interactions, and their contributions to maintaining soil structure. The symbiosis is faced with numerous challenges in agroecosystems; in order to inform sustainable management strategies it is hence a high priority to work towards mechanistic understanding of arbuscular mycorrhizae contributions to soil quality. This review focuses on glomalin-related soil protein (GRSP), operationally defined soil C pools that have been linked to arbuscular mycorrhizal fungi (AMF). In discussing this protein pool, we propose a new terminology used to describe fractions of soil proteins and glomalin. GRSP concentrations in soil are positively correlated with aggregate water stability. GRSP has relatively slow turnover in soil, contributing to lasting effects on aggregation. Controls on production of GRSP at the phenomenological and mechanistic level are evaluated. While there are significant gaps in our knowledge about GRSP and glomalin (particularly at the biochemical level), it is concluded that research on GRSP holds great promise for furthering our knowledge of soil structure and quality, for informing suitable management, and as a foundation for novel biotechnological applications in agriculture and beyond. Key words: Glomalin, GRSP, soil structure, land use, restoration, soil protein, sustainability, arbuscular mycorrhizae

FIRST REPORT OF THE ESTABLISHMENT OF AGAPETA ZOEGANA L. (LEPIDOPTERA: COCHYLIDAE) ON SPOTTED KNAPWEED, CENTAUREA MACULOSA LAMARCK, IN THE UNITED STATES

1991 ◽  
Vol 123 (2) ◽  
pp. 411-412 ◽  
Author(s):  
J.M. Story ◽  
K.W. Boggs ◽  
W.R. Good
Keyword(s):  
United States ◽  
North America ◽  
The United States ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
Root Cortex ◽  
New Host ◽  
Early Instar ◽  
Below Ground ◽  
Considerable Damage

Agapeta zoegana L. (Lepidoptera: Cochylidae) is a Eurasian root-mining moth introduced into North America for control of spotted knapweed, Centaurea maculosa Larnarck. The biology and host specificity of the moth were described by Müller et al. (1988, 1989). Early-instar larvae mine the epidermal tissues of the root crown. Older larvae mine the root cortex and endodermis and cause considerable damage, especially to small plants or when several larvae infest a single large plant. Larvae can migrate below ground to a new host plant if the initial knapweed plant has been destroyed. The moth overwinters as a larva in the root and emerges as an adult in June through August. Several generations per year may occur.

FIRST REPORT OF THE ESTABLISHMENT OF CYPHOCLEONUS ACHATES (FAHRAEUS) (COLEOPTERA: CURCULIONIDAE) ON SPOTTED KNAPWEED, CENTAURE A MACULOSA LAMARCK, IN THE UNITED STATES

1997 ◽  
Vol 129 (2) ◽  
pp. 373-374 ◽  
Author(s):  
J.M. Story ◽  
W.R. Good ◽  
L.J. White
Keyword(s):  
United States ◽  
Biological Control ◽  
North America ◽  
Host Specificity ◽  
The United States ◽  
Centaurea Maculosa ◽  
Spotted Knapweed ◽  
Root Cortex ◽  
Potential Impact ◽  
Root Feeding

Cyphocleonus achates (Fahaeus) is a Eurasian, root-feeding weevil introduced into North America for the biological control of spotted knapweed, Centaurea maculosa Lamarck. Stinson et al. (1994) reported that C. achates is one of the most damaging root-feeding insects on knapweed in Eurasia and should be a valuable addition to the biocontrol effort in North America. The biology, host specificity, and potential impact of the weevil were described by Stinson et al. (1994). Larvae mine into the root cortex where they induce formation of a conspicuous root gall. Feeding by older larvae causes much damage, especially to small plants or plants containing several larvae. The weevil overwinters as a larva in the root and emerges as an adult from mid-July to October. Adult weevils are large (14 mm long) and flightless, and feed on knapweed foliage. The weevil has one generation per year.

scholarly journals Risk assessment for the establishment of the Asian giant hornet (Vespa mandarinia) in the Pacific Northwest

2021 ◽  
Author(s):  
Erik D. Norderud ◽  
Scott L. Powell ◽  
Robert K. D. Peterson
Keyword(s):  
Risk Assessment ◽  
High Risk ◽  
Pacific Northwest ◽  
Forest Biomass ◽  
The United States ◽  
Quantitative Risk Assessment ◽  
Negative Effects ◽  
Pollination Services ◽  
Introduction Pathways ◽  
The Pacific

AbstractThe recent introduction of the Asian giant hornet (Vespa mandarinia Smith) in the United States in late 2019 has raised concerns about its establishment in the Pacific Northwest and its potential deleterious effects on honey bees and their pollination services in the region. Therefore, we conducted a risk assessment of the establishment of V. mandarinia in Washington and Oregon on a county-by-county basis. Our tier-1 qualitative and semi-quantitative risk assessment relied on the biological requirements and ecological relationships of V. mandarinia in the environments of the Pacific Northwest. We based the risk characterization on climate and habitat suitability estimates for V. mandarinia queens to overwinter and colonize nests, density and distribution of apiaries, and locations of major human-mediated introduction pathways that may increase establishment of the hornet in the counties of Washington and Oregon. Our results suggest that 5 counties in the region could be at low risk, 48 at medium risk, and 22 at high risk of establishment. For Washington, counties at high risk included Clallam, Clark, Cowlitz, Grays Harbor, King, Pierce, Skagit, Snohomish, and Whatcom. The high risk Oregon counties included Benton, Clackamas, Clatsop, Coos, Douglas, Hood River, Lane, Lincoln, Linn, Marion, Multnomah, Polk, and Yamhill. Many of the western counties of both Washington and Oregon were estimated to be at the highest risk of establishment mainly due to their suitable climate for queens to overwinter, dense forest biomass for nest colonization, and proximity to major port and freight hubs in the region. Considering its negative effects, these counties should be prioritized in ongoing monitoring and eradication efforts of V. mandarinia.

Diversification for new management systems opportunities in the Pacific Northwest

1996 ◽  
Vol 11 (2-3) ◽  
pp. 77-82 ◽  
Author(s):  
L.F. Elliott ◽  
P. Chevalier
Keyword(s):  
United States ◽  
Soil Quality ◽  
Pacific Northwest ◽  
The United States ◽  
Water Erosion ◽  
Biological Properties ◽  
Water Infiltration ◽  
Residue Management ◽  
The Pacific ◽  
Wind And Water Erosion

Sustainable rainfed cropping systems are needed in the Pacific Northwest of the United States to reduce or eliminate wind and water erosion, improve soil quality, and control weeds with reduced chemical inputs. A grass seed cropping system is excellent for improving soil quality and for controlling erosion, and can be grazed by sheep to produce meat and wool Tilla ge and residue management methods that create a rough surface to reduce wind and water erosion and increase water infiltration include: use of a chisel to create large clods; leaving residue on the surface; and use of the Paratill to shatter the soil to increase water infiltration with little disturbance of the soil surface. Including a legume in the rotation may help to break disease cycles, add N and C to the soil, and improve soil biological properties. The use of surface residues and tillage to control erosion and increase water infiltration may demand new approaches to weed contro I Rhizobacteria that attack the roots of weeds but not of wheat may reduce the need for chemica I herbicides. Research being conducted on these techniques in the Pacific Northwest of the United States and in other countries should soon result in guidelines for sustainable agricultural systems for the dryland, rainfed areas of the world.

Mycorrhizal dependence of modern wheat varieties, landraces, and ancestors

1992 ◽  
Vol 70 (10) ◽  
pp. 2032-2040 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
T. S. Cox
Keyword(s):  
United States ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Dry Weight ◽  
The United States ◽  
Grass Species ◽  
Aegilops Speltoides ◽  
Wheat Cultivars ◽  
Wheat Varieties ◽  
Mycorrhizal Response

Using mycorrhizal fungi known to colonize wheat, the mycorrhizal dependence of various small grains including modem wheat varieties, primitive wheat lines, and wheat ancestors was studied. With the exception of the United States cultivar Newton and the German cultivars Apollo, Kanzler, and Sperber, dry weight of eight other modern wheats from the United States and Great Britain were increased by 29–100% following inoculation with mycorrhizal fungi. All landraces from Asian collections or early introduced American cultivars were also dependent on the symbiosis, with dry weight increases averaging 169 and 55%, respectively. All wheat ancestors of the AA and BB genomes (except Aegilops speltoides) benefitted significantly from the symbiosis, whereas no benefit was observed for ancestors of the DD genome, tetraploid wheats of the AABB or AAGG genomes, or in the hexaploid ancestor Triticum zhukovskyi (AAAAGG genome). These differences in mycorrhizal response of the ancestors, lines, and cultivars were highly correlated with root fibrousness ratings. When the fungi used as a combined inoculum in the previous experiment were inoculated individually onto selected plant species or cultivars, 6 of the 10 isolates stimulated growth of Andropogon gerardii, a highly dependent grass species, and 8 of the 10 stimulated the growth of 'Turkey' wheat. In contrast, none of the isolates positively affected growth of 'Newton' or 'Kanzler' wheat cultivars, and in fact several fungi decreased the biomass produced by these two cultivars. These studies have demonstrated a strong genetic basis for differences in mycorrhizal dependence among cultivars. A trend for greater reliance on the symbiosis in older cultivated wheats than iin wheat ancestors or modern wheats was also observed. The depression in growth associated with certain mycorrhizal fungi and wheat cultivars demonstrates that colonization of roots does not guarantee benefit from the symbiosis. Key words: root fibrousness, growth response, vesicular–arbuscular mycorrhizae.

Undesirable Effects of Goal Setting on Perceived Fairness, Commitment, and Unethical Behavior

2018 ◽  
Vol 62 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Nina Keith
Keyword(s):  
Goal Setting ◽  
Unethical Behavior ◽  
The United States ◽  
Goal Commitment ◽  
Management Technique ◽  
Long Term Effects ◽  
Perceived Fairness ◽  
Negative Effects ◽  
Positive Effects ◽  
And Performance

Abstract. The positive effects of goal setting on motivation and performance are among the most established findings of industrial–organizational psychology. Accordingly, goal setting is a common management technique. Lately, however, potential negative effects of goal-setting, for example, on unethical behavior, are increasingly being discussed. This research replicates and extends a laboratory experiment conducted in the United States. In one of three goal conditions (do-your-best goals, consistently high goals, increasingly high goals), 101 participants worked on a search task in five rounds. Half of them (transparency yes/no) were informed at the outset about goal development. We did not find the expected effects on unethical behavior but medium-to-large effects on subjective variables: Perceived fairness of goals and goal commitment were least favorable in the increasing-goal condition, particularly in later goal rounds. Results indicate that when designing goal-setting interventions, organizations may consider potential undesirable long-term effects.

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