scholarly journals Poecilus lucublandus (Coleoptera: Carabidae) and Pterostichus mutus Do Not Feed on Hair Fescue, Red Sorrel, and Poverty Oatgrass Seeds

2019 ◽  
Vol 19 (2) ◽  
Author(s):  
Alexandre M M C Loureiro ◽  
G Christopher Cutler ◽  
Vilis O Nams ◽  
Scott N White
Keyword(s):  
Seed Predation ◽  
Choice Test ◽  
Weed Seed ◽  
Weed Species ◽  
Vaccinium Angustifolium ◽  
Lowbush Blueberry ◽  
Rumex Acetosella ◽  
Weed Seeds ◽  
Poecilus Lucublandus ◽  
Danthonia Spicata

Abstract Poecilus lucublandus (Say), Pterostichus mutus (Say), and Harpalus rufipes (De Geer) are abundant Carabidae in lowbush blueberry fields and may contribute to weed seed predation. We used laboratory no-choice test experiments to determine if these beetles feed on seeds of hair fescue (Festuca filiformis Pourr., Poales: Poaceae), poverty oatgrass (Danthonia spicata L.), and red sorrel (Rumex acetosella L., Caryophyllales: Polygonaceae), which are common weeds in lowbush blueberry (Vaccinium angustifolium Ait., Ericales: Ericaceae) fields. Poecilus lucublandus and P. mutus did not feed on seeds of the test weed species, but H. rufipes consumed on average over 30 seeds of each species. There are other weed seeds in blueberry fields that could be palatable to P. lucublandus and P. mutus, which warrants further research on the granivory potential of these important carabid species.

Studies on the flowering biology of red sorrel (Rumex acetosella) ramets from lowbush blueberry (Vaccinium angustifolium) fields in Nova Scotia, Canada

Botany ◽  
2015 ◽  
Vol 93 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd ◽  
Rene C. Van Acker ◽  
Clarence J. Swanton
Keyword(s):  
Nova Scotia ◽  
Combined Effects ◽  
Perennial Species ◽  
Weed Species ◽  
Vaccinium Angustifolium ◽  
Perennial Weed ◽  
Flowering Response ◽  
Lowbush Blueberry ◽  
Rumex Acetosella

Red sorrel (Rumex acetosella L.) is a ramet-producing herbaceous creeping perennial species commonly found as a weed in commercially managed lowbush blueberry (Vaccinium angustifolium Aiton) fields in Nova Scotia, Canada. Flowering and seed production occur primarily in overwintering ramets of this species, indicating a potential vernalization requirement for flowering. This study was therefore initiated to examine the role of vernalization, photoperiod, and pre-vernalization stimulus on ramet flowering. Red sorrel ramets propagated from creeping roots and seeds collected from established red sorrel populations in lowbush blueberry had an obligate requirement for vernalization to flower. Ramet populations maintained under pre- and post-vernalization photoperiods of 16 h flowered following 12 weeks of vernalization at 4 ± 0.1 °C, whereas those maintained under constant 16, 14, or 8 h photoperiods without vernalization did not flower. Vernalization for 10 weeks maximized, but did not saturate, the flowering response. Pre-vernalization photoperiod affected flowering response, with increased flowering frequency observed in ramet populations exposed to decreasing, rather than constant, photoperiod prior to vernalization. This study represents the first attempt to determine the combined effects of vernalization and photoperiod on red sorrel flowering, and the results provide a benchmark for the future study of flowering and sexual reproduction in this economically important perennial weed species.

Weed seed contamination in white clover seedlots

1990 ◽  
pp. 99-102
Author(s):  
J.S. Rowarth ◽  
A.A. Johnson ◽  
P.T.P. Clifford ◽  
M.P. Rolston
Keyword(s):  
White Clover ◽  
Chenopodium Album ◽  
Cirsium Arvense ◽  
Weed Seed ◽  
Weed Species ◽  
Stellaria Media ◽  
Seed Testing ◽  
Rumex Acetosella ◽  
Weed Seeds ◽  
Californian Thistle

Weed seeds are the major reason for white clover (Trifolium repens) seedlots being downgraded or rejected from certification. The occurrence of weed species in 537 white clover seedlots tested at the Official Seed Testing Station, Palmerston North, was analysed. The most commonly occurring species were field madder (Sherardia arvensis), chickweed (Stellaria media), fathen (Chenopodium album), sheep's sorrel (Rumex acetosella) and scarlet pimpernel (Anagaflis arvensis). The percentage occurrence of four specified undesirable weeds including Californian thistle (Cirsium arvense) and dodder (Cuscuta epithymum) are reported, and the implications of seed contamination are discussed. Keywords: white clover, contamination, weed seeds

scholarly journals Influence of crop rotation, tillage, and management inputs on weed seed production

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 175-183 ◽  
Author(s):  
George O. Kegode ◽  
Frank Forcella ◽  
Sharon Clay
Keyword(s):  
Seed Production ◽  
Crop Rotation ◽  
Crop Production ◽  
Conservation Tillage ◽  
Farming Systems ◽  
Crop Rotations ◽  
Weed Seed ◽  
Weed Species ◽  
Weed Seeds ◽  
Ridge Tillage

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to 1994, average grass weed seed productions were 7.3 by 103, 3.7 by 1036.1 by 103and 5.7 by 103seeds m−-2, whereas average broad-leaved weed seed productions were 0.4 by 103, 0.4 by 103, 1.4 by 103, and 0.4 by 103seeds m−-2in crop rotations using conventional tillage (moldboard plow), conservation tillage, no tillage, and ridge tillage, respectively. Crop rotations using conventional or ridge tillage consistently produced more grass and broad-leaved weed seeds, especially in low-input plots. There was little difference in weed seed production among input levels for crop rotations using conservation tillage. Comparing rotations that began and ended with a corn crop revealed that by increasing crop diversity within a rotation while simultaneously reducing the amount of tillage, significantly fewer grass and broad-leaved weed seeds were produced. Among the rotations, grass and broad-leaved weed fecundity were highly variable, but fecundity declined from 1990 to 1994 within each rotation, with a concomitant increase in grass and broad-leaved weed density over the same period. Crop rotation in combination with reduced tillage is an effective way of limiting grass and broad-leaved weed seed production, regardless of the level of management input applied.

Effect of Dry Heat, Direct Flame, and Straw Burning on Seed Germination of Weed Species Found in Lowbush Blueberry Fields

2016 ◽  
Vol 30 (1) ◽  
pp. 263-270 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd
Keyword(s):  
Seed Germination ◽  
Exposure Time ◽  
Heat Exposure ◽  
Seed Viability ◽  
Weed Species ◽  
Dry Heat ◽  
Lowbush Blueberry ◽  
Weed Seeds ◽  
Straw Burning ◽  
Time Required

Experiments were conducted to determine the effects of dry heat, direct flame, and straw burning on germination of several weed species from lowbush blueberry fields. Dry heat experiments were designed as factorial arrangements of temperature (100, 200, and 300 C in experiment 1 and room temperature, 100, 200, and 300 C in experiment 2) and exposure time (0, 5, 10, 20, 40, and 80 s in experiment 1 and 2, 5, 10, and 20 s in experiment 2) to determine the exposure time required to reduce germination for each temperature. Susceptibility to dry heat varied across species tested, but germination of spreading dogbane, meadow salsify, fireweed, and hair fescue seeds collected from lowbush blueberry fields in Nova Scotia, Canada generally declined exponentially as a function of duration of heat exposure at the temperatures tested. Germination decreased more rapidly at higher temperatures in all species, although the duration of heat exposure required to reduce germination by 50 and 90% varied across temperatures and species. Exposure of seeds to direct flame rapidly reduced germination, with less than 1 s of exposure required to reduce seed germination of witchgrass, spreading dogbane, and meadow salsify by > 90%. Straw burning did not consistently reduce germination of hair fescue or winter bentgrass, indicating that a surface burn occurring above weed seeds may not be consistently effective at reducing seed viability. These results provide important estimates of the temperature and exposure times required to reduce viability of weed seeds in lowbush blueberry fields and suggest that thermal technologies that expose weed seeds to direct flame will be the most consistent in reducing seed viability.

Effects of Initial Seed-Bank Density on Weed Seedling Emergence during the Transition to an Organic Feed-Grain Crop Rotation

Weed Science ◽  
2009 ◽  
Vol 57 (5) ◽  
pp. 533-540 ◽  
Author(s):  
Richard G. Smith ◽  
Randa Jabbour ◽  
Andrew G. Hulting ◽  
Mary E. Barbercheck ◽  
David A. Mortensen
Keyword(s):  
Seed Bank ◽  
Weed Management ◽  
Cover Crop ◽  
Management Practices ◽  
Transition Period ◽  
Red Clover ◽  
Weed Seed ◽  
Weed Species ◽  
Organic Certification ◽  
Weed Seeds

The transition period to certified organic production can present a significant weed management challenge for growers. Organic certification requires that prohibited fertilizers and pesticides must not have been used for 36 mo before harvest of the first organic crop. Understanding how organic management practices and initial weed seed-bank densities affect weed population dynamics during the transition period may improve weed management efficacy and adoption of organic practices. We examined how tillage systems (full or reduced) and cover crop species planted during the first transition year (rye or a mixture of timothy and red clover) affect the seedling densities of three common annual weed species, common lambsquarters, velvetleaf, and foxtail spp., during the 3-yr transition period. Weed seeds were applied in a one-time pulse at the beginning of the study at three densities, low, medium, and high (60, 460, and 2,100 seeds m−2, respectively), and cumulative seedling densities of each species were assessed annually. Treatment factors had variable and species-specific effects on weed seedling densities. In general, the full-tillage system, with an initial cover crop of timothy and red clover, resulted in the lowest density of weed seedlings following seed-bank augmentation. There was little consistent association between the initial densities of applied weed seeds in the weed seed bank at the start of the transition and weed seedling densities at the end of the transition period. This suggests that when multiple crop and weed cultural management practices are employed during the organic transition period, initial failures in weed management may not necessarily lead to persistent and intractable annual weed species management problems following organic certification.

Factors Affecting Weed Seed Devitalization with the Harrington Seed Destructor

Weed Science ◽  
2017 ◽  
Vol 65 (5) ◽  
pp. 650-658 ◽  
Author(s):  
Breanne D. Tidemann ◽  
Linda M. Hall ◽  
K. Neil Harker ◽  
Hugh J. Beckie
Keyword(s):  
Seed Size ◽  
Cropping Systems ◽  
Weed Seed ◽  
Weed Species ◽  
Factors Affecting ◽  
Weed Seeds ◽  
High Control ◽  
Relationship Of ◽  
The Impact ◽  
Levels Of Control

The Harrington Seed Destructor (HSD), a novel weed control technology, has been highly effective in Australian cropping systems. To investigate its applicability to conditions in western Canada, stationary threshing was conducted to determine the impact of weed species, seed size, seed number, chaff load, and chaff type on efficacy of seed destruction. Control varied depending on species, with a range of 97.7% to 99.8%. Sieve-sized volunteer canola seed had a linear relationship of increasing control with increasing 1,000-seed weight. However, with greater than 98% control across all tested seed weights, it is unlikely that seed size alone will significantly influence control. Consistently high levels of control were observed at all tested seed densities (10 seeds to 1 million seeds). The response of weed seed control to chaff load was quadratic, but a narrow range of consistently high control (>97%) was again observed. Chaff type had a significant effect on weed seed control (98% to 98.6%); however, seed control values in canola chaff were likely confounded by a background presence of volunteer canola. Overall, the five parameters studied statistically influence control of weed seeds with the HSD. However, small differences between treatments are unlikely to affect the biological impact of the machine, which provides high levels of control for those weed seeds that can be introduced into the harvester.

Weed Seed Banks Are More Dynamic in a Sod-Based, Than in a Conventional, Peanut–Cotton Rotation

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 877-887 ◽  
Author(s):  
Ramon G. Leon ◽  
David L. Wright ◽  
James J. Marois
Keyword(s):  
Crop Rotation ◽  
Seed Bank ◽  
Seed Banks ◽  
Community Diversity ◽  
Weed Seed ◽  
Weed Species ◽  
Perennial Crop ◽  
Seed Bank Dynamics ◽  
Weed Seeds ◽  
Grass Weed

Crop rotation promotes productivity, nutrient cycling, and effective pest management. However, in row-crop systems, rotation is frequently limited to two crops. Adding a third crop, especially a perennial crop, might increase crop-rotation benefits, but concerns about disruption of agricultural and ecological processes preclude grower adoption of a three-crop rotation. The objective of the present research was to determine whether weed seed banks differ between a sod-based rotation (bahiagrass–bahiagrass–peanut–cotton) and a conventional peanut–cotton rotation (peanut–cotton–cotton) and the importance of crop phase in weed seed-bank dynamics in a long-term experiment initiated in 1999 in Florida. Extractable (ESB) and germinable (GSB) seed banks were evaluated at the end of each crop phase in 2012 and 2013, and total weed seed or seedling number, Shannon-Weiner's diversity (H′), richness, and evenness were determined. ESB increased in H′ (36%), richness (29%), and total number of weed seeds (40%) for sod-based compared with conventional rotation, whereas GSB increased 32% in H′, 27% in richness, and 177% in total number of weed seedlings. Crop phase was a determinant factor in the differences between crop rotations. The first year of bahiagrass (B1) exhibited increases in weed seed and seedling number, H′, and richness and had the highest values observed in the sod-based rotation. These increases were transient, and in the second year of bahiagrass (B2), weed numbers and H′ decreased and reached levels equivalent to those in the conventional peanut–cotton rotation. The B1 phase increased the germinable fraction of the seed bank, compared with the other crop phases, but not the total number of weed seeds as determined by ESB. The increases in H′ and richness in bahiagrass phases were mainly due to grass weed species. However, these grass weed species were not associated with peanut and cotton phases of the sod-based rotation. The results of the present study demonstrated that including bahiagrass as a third crop in a peanut–cotton rotation could increase weed community diversity, mainly by favoring increases in richness and diversity, but the structure and characteristics of the rotation would prevent continuous increases in the weed seed bank that could affect the peanut and cotton phases.

scholarly journals Weed seed survival in experimental mini-silos of corn and alfalfa

2016 ◽  
Vol 96 (3) ◽  
pp. 448-454 ◽  
Author(s):  
Marie-Josée Simard ◽  
Camille Lambert-Beaudet
Keyword(s):  
Seed Dispersal ◽  
Seed Coat ◽  
Storage Time ◽  
Weed Seed ◽  
Weed Species ◽  
Water Imbibition ◽  
Nylon Mesh ◽  
Silage Fermentation ◽  
Weed Seeds ◽  
Mesh Bags

Weed seeds present in harvested silage have to survive silage fermentation and rumen digestion before they are dispersed as a contaminant of manure. Therefore, producing crops that are ensiled could lower the seed dispersal of weed escapes. This study is aimed at evaluating the viability of seven weed species after storage in experimental mini-silos filled with corn or alfalfa. Nylon mesh bags, each containing one hundred seeds of a weed species, were inserted at random locations in mini-silos filled with silage corn or alfalfa and stored for one, three or six months. The experiment included five mini-silos per storage time as well as untreated seeds. Water imbibition by intact seeds was also evaluated to determine if it could be related with survival in silage. After three and six months of storage few seeds were viable in any treatment (<0.1% of all seeds tested). Differences between weed species and silage type were observable after one month of storage and could not be related to seed coat permeability as measured by water imbibition. Ensiling for three to six months, or more, could be used to kill harvested weed seeds. Further evaluations in commercial farm silos could be done to support results.

scholarly journals Targeting Weed Seeds In-Crop: A New Weed Control Paradigm for Global Agriculture

2013 ◽  
Vol 27 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Michael Walsh ◽  
Peter Newman ◽  
Stephen Powles
Keyword(s):  
Weed Control ◽  
Control Strategies ◽  
Weed Seed ◽  
Weed Species ◽  
New Paradigm ◽  
Control Paradigm ◽  
Weed Seeds ◽  
Global Agriculture ◽  
Annual Weeds ◽  
Herbicide Use

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting Australian cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest. Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided Australian grain cropping and their potential utility in global agriculture.

scholarly journals Pest and weed seed predation in field defects within oilseed rape crops

2019 ◽  
Vol 2 ◽  
Author(s):  
Ezequiel González ◽  
Miroslav Seidl ◽  
Martin Štrobl ◽  
Tomáš Kadlec ◽  
Marco Ferrante ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Seed Predation ◽  
Weather Conditions ◽  
Ground Beetles ◽  
Agricultural Landscapes ◽  
Feeding Guilds ◽  
Weed Seed ◽  
Weed Species ◽  
Activity Density ◽  
Field Defects

Non-crop habitats can act as refuge for insects in agricultural landscapes and increase ecosystem services (ESs) in neighboring arable fields. Among the different types of non-crop habitats, field defects are temporary patches where sown plants are poorly developed and other plant species emerge. These defects can be common and large in years with extreme weather conditions. However, their relevance as habitat for beneficial insects and ESs provision is unknown. Here, we quantified two ESs (pest and weed seed predation) in field defects within oilseed rape crops and related ESs levels with the activity-density of ground beetles and temperature. In 10 fields, we used artificial caterpillars made of plasticine and seed cards of two weed species (Taraxacum sp. and Stellaria sp.) to quantify ESs in two sampling periods (spring and summer) and in three habitat types: field defects, standardly grown crop (field interiors) and crop-defect boundaries. Ground beetles were sampled using pitfall traps and classified into feeding guilds and body size classes. Insects and mammals were the main pest predators and predation increased in summer, but did not differ among habitats. Seed predation rates for both species were significantly higher in summer. Predation of Taraxacum seeds was higher at field interiors, whereas predation of Stellaria was significantly higher at field interiors and defects, compared to crop-defect boundaries. Insect predation increased with the activity-density of medium and large carnivorous carabids, whereas seed predation for both weed species was positively related to the activity-density of medium-sized herbivorous carabids. Finally, temperature was negatively linked to predation of artificial caterpillars and seeds of Taraxacum.

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