Variation in postdispersal weed seed predation in a crop field

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 148-155 ◽  
Author(s):  
Helen Spafford Jacob ◽  
David M. Minkey ◽  
Robert S. Gallagher ◽  
Catherine P. Borger

Postdispersal weed seed predation by animals during the summer fallow period may lead to a reduction in the number of weeds that grow in the following winter cropping season. In this study, we investigated the patterns of weed seed removal, the influence of crop residue cover on seed removal, the types of granivores present and their seed preferences in a 16-ha postharvest cropping field in Western Australia during the summer months over 2 yr. Seed removal from caches was extremely variable (from 0 to 100%). Removal rates were generally highest along the edges of the field near bordering vegetation and lowest in the center of the field and within the bordering vegetation. However, there were many deviations from this general pattern. There was no change in rates of predation with different levels of residue cover. Ants or other small invertebrates were found to remove the most seeds. However, seed removal by other animals, such as rodents, was also evident. Annual ryegrass seeds were preferred over wild oat seeds, followed by wild radish pod segments. Seed harvesting was lowest in late January, peaked in February, and decreased in March. Results from this study suggest seed harvesters could reduce the number of surface seeds in the field, reducing the weed seed bank. Management options that increase the activity of the seed harvesters may lead to less variability in seed predation and could, therefore, be incorporated into an integrated weed management program.

Weed Science ◽  
2005 ◽  
Vol 53 (4) ◽  
pp. 465-470 ◽  
Author(s):  
Steven J. Shirtliffe ◽  
Martin H. Entz

Combine harvesters have the potential to disperse weed seeds great distances. Reducing this dispersal may be important in an integrated weed management system. The objectives of this study were to determine the distance that wild oat seeds are dispersed by a combine harvester and the effect of chaff collection on combine harvester seed dispersal. This was measured by sampling wild oat seeds at varying distances behind a combine equipped with a removable chaff collection system after it passed through a wild oat patch. Chaff collection consistently reduced the amount and distance that wild oat seeds were dispersed. This occurred because more than 74% of the total wild oat seed that were ejected from the combine were in the chaff. Because most of the chaff falls in a row directly behind the combine, chaff collection only affected dispersal in this area. In 1996, chaff collection reduced wild oat seed dispersal past the wild oat patch to less than 10 seeds m−2at 45 m, whereas without chaff collection, there was greater than 10 seeds m−2up to 145 m. At distances beyond 145 m, chaff collection had no significant effect on seed dispersal. Chaff collection may be an important tool in an integrated weed management program because it may slow weed invasions and reduce the expansion of weed patches.


Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 876
Author(s):  
Iñigo Loureiro ◽  
Inés Santin-Montanyá ◽  
María-Concepción Escorial ◽  
Esteban García-Ruiz ◽  
Guillermo Cobos ◽  
...  

A farm-scale investigation was conducted to evaluate the potential impact of integrating glyphosate into different weed management programs when cultivating herbicide-tolerant maize in central Spain from 2012 to 2014. The weed management programs were (1) a conventional weed management with pre- and post-emergent herbicide applications, (2) a weed management program in which the number and total amount of conventional herbicides applied were reduced, and (3) three weed management programs that comprised either two post-emergent applications of the herbicide glyphosate, or only one glyphosate application combined with pre- and/or post-emergent herbicides. Weed density throughout each cropping season was greater in those weed management programs that did not include a pre-emergence application of herbicides than those that did. Moreover, none of the weed management programs affected the richness and species diversity of the weeds or reduced yields. Although the impact of the different programs was similar in terms of weed species diversity, the composition of the weed community differed and this effect must be considered when providing agroecosystem services. Our results indicate that glyphosate-tolerant maize provides an additional tool that allows integrated weed control of the weed populations without reducing yields.


Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 355-376 ◽  
Author(s):  
Sharavari S. Kulkarni ◽  
Lloyd M. Dosdall ◽  
Christian J. Willenborg

Weed management is a challenge in all agroecosystems. Given the negative consequences associated with herbicide-based weed management, it is important to consider integrated weed management options with emphasis on strategies such as biological control. Postdispersal weed seed predation by granivorous and omnivorous carabid beetles results in substantial natural suppression of weed populations. Although the role of ground beetles as “generalist predators” in various agroecosystems is known, their contribution to weed management is not well recognized. In this context, this review presents an account of carabids and their granivorous nature, the importance of a seed diet in the life histories of different carabid groups, factors affecting granivory, and their potential role in weed seed management. Below, we discuss the interrelationships among various factors influencing weed seed consumption by carabids, its consequences for weed management, and the need for future research.


Weed Science ◽  
2016 ◽  
Vol 64 (2) ◽  
pp. 294-302 ◽  
Author(s):  
Sharavari S. Kulkarni ◽  
Lloyd M. Dosdall ◽  
John R. Spence ◽  
Christian J. Willenborg

We used laboratory and field feeding trials to investigate adult carabid beetle preferences for three brassicaceous weed species (rapeseed, wild mustard, and field pennycress) that are pests in canola. All carabid species preferred seeds of rapeseed most and those of field pennycress least and showed intermediate preference for wild mustard seeds. Beetles highly preferred imbibed seeds of all three weed species. Activity–density of carabids and mean weed seed removal were highly correlated in field plots of canola, with activity–density accounting for 67% of the observed variation in seed removal. Our study indicates that seed consumption among carabids is influenced by several factors, including weed species, physiological state of seeds, and carabid activity–density. Carabid seed predation is significant in canola agroecosystems; therefore, understanding these influences has implications for ecological weed management.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1565
Author(s):  
María Belén D’Amico ◽  
Guillermo R. Chantre ◽  
Guillermo L. Calandrini ◽  
José L. González-Andújar

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.


Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 683-694 ◽  
Author(s):  
Alberto Collavo ◽  
Silvia Panozzo ◽  
Antonio Allegri ◽  
Maurizio Sattin

Italian ryegrass populations investigated in this study were harvested in an alfalfa-based cropping system. In that system, the agronomic practices and chemical weed management, based on the use of aryloxyphenoxy-propionates herbicides (i.e., quizalofop ethyl ester), were optimized to obtain a dual seed–forage production. Five of seven populations tested were confirmed resistant to quizalofop ethyl ester with resistance indexes ranging from 4.5 to >209. Both target- and nontarget-site resistance mechanisms were most likely involved. Three allelic variants were detected (Ile-1781–Leu, Trp-2027–Cys, and Ile-2041–Asn) in four resistant populations, whereas no known mutations were found in one resistant population. The herbicide treatment on Italian ryegrass plants at different phenological stages suggested that to control regrowth, it is necessary to use two to fives times the herbicide dose suitable for younger plants. This situation is encountered in fields when Italian ryegrass plants need to be controlled to maximize the alfalfa seed production, and it is comparable to using a sublethal herbicide dose, leading to the selection of herbicide-resistant biotypes. In such a situation, the cropping system is not sustainable, and integrated weed management should be implemented to deplete the soil weed seed bank and prevent new weed seed production.


2004 ◽  
Vol 18 (3) ◽  
pp. 648-657 ◽  
Author(s):  
Hilary A. Sandler ◽  
Joanne Mason ◽  
Wesley R. Autio ◽  
Thomas A. Bewick

To address grower concerns that repeated use of dichlobenil could negatively affect cranberry productivity, field studies were conducted at two commercial farms in either high weed density (HW) or low weed density (LW) areas. Data from 4 yr of repeat annual applications of 0, 1.8, and 4.5 kg ai/ha dichlobenil indicated minimal negative impact on cranberry vines. Herbicide application did not affect upright productivity, leaf biomass production, percent fruit set, or other yield parameters adversely; in addition, no improvement in these parameters was noted. Although the interaction of herbicide application with weed density on cranberry root length varied with sampling date, no consistent trend (adverse or positive) was seen. The presence of weeds, rather than herbicide application, was the important determinant of yield. Vines in LW areas produced more marketable fruit and had higher percentage of fruit set than vines growing in HW areas. Repeat annual applications of dichlobenil on commercial cranberry beds may be considered as part of a viable integrated weed management program with no adverse effect on crop growth or yield.


2015 ◽  
Vol 29 (3) ◽  
pp. 509-518 ◽  
Author(s):  
William S. Curran ◽  
John M. Wallace ◽  
Steven Mirsky ◽  
Benjamin Crockett

A field experiment was conducted in 2009–2010 at Pennsylvania and Maryland locations, and repeated it in 2010–2011 to test the effectiveness of POST-applied herbicides at fall and spring timings on seeded hairy vetch in winter wheat. A total of 16 herbicide treatment combinations was tested that included synthetic auxins, acetolactate synthase (ALS) inhibitors, and a protoporphyrinogen oxidase inhibitor. Spring applications tended to be more effective than fall applications. Among synthetic auxins, clopyralid (105 g ae ha−1) and treatments containing dicamba (140 g ae ha−1) were effective at both timings, resulting in greater than 90% hairy vetch control at wheat harvest. Pyroxsulam and prosulfuron applied at 18 g ai ha−1 provided the most effective hairy vetch control (> 90%) at both application timings among ALS inhibitors. Spring applications of several herbicides provided moderate (> 80%) to high (> 90%) levels of hairy vetch control, including: 2,4-D amine (140 g ae ha−1), mesosulfuron-methyl (15 g ai ha−1), tribenuron-methyl (13 g ai ha−1), and thifensulfuron/tribenuron-methyl treatments (16 and 32 g ai ha−1). Winter wheat injury was evaluated, but symptoms were negligible for most treatments. Winter wheat yields declined with increasing hairy vetch biomass. Fall herbicides may be prioritized to reduce hairy vetch competition during the fall and early spring growing season. Our research has established that several synthetic auxin and ALS-inhibiting herbicides, applied POST in fall or spring, can be safely used in winter wheat to control hairy vetch in an integrated weed management program.


2016 ◽  
Vol 44 (2) ◽  
pp. 111
Author(s):  
Usman , ◽  
Bambang Sapta Purwoko ◽  
Muhamad Syukur ◽  
Dan Dwi Guntoro

<em>ABSTRACT<br /><br />Barnyard grass (Echinochloa crus-galli (L.) P. Beauv.) is a major weed competitor to rice production in Indonesia. In order to develop integrated weed management program, a research to select competitive rice lines to E. crus-galli was conducted in a green house of Indonesian Centre of Agricultural Biotechnology and Genetic Resource Research and Development Bogor. The research design was split plot with four replications, E. crus-galli was designed as the main plot (rice without E. crus-galli compared  rice with four E. crus-galli per pot), and the sub-plots were 25 genotypes (23 lines, 1 tolerant variety and 1 sensitive variety). Level of tolerance was determined by the reduction percentage of grains weight, the number of productive tillers and dry matter weight. The results showed that rice competition with E. crus-galli reduced plant height, productive tiller numbers, filled spikelet numbers per panicle, dry matter weight and dry grain weight. Three lines, i.e., IR10L-155, IR10L-133 and BIO-R84-1 were classified as tolerant, 19 lines were moderate and 3 lines were sensitive to E. crus-galli competition.<br /><br />Keywords: Barnyard grass, competition, sensitive line, yield reduction </em>


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 292
Author(s):  
Prashant Sharma ◽  
Manoj Kumar Singh ◽  
Kamlesh Verma ◽  
Saroj Kumar Prasad

The rice–wheat cropping system in the Indo-Gangetic Plains is the backbone of food security in India. In the 1990s, due to the scarcity of resources, the traditional Crop Establishment (CE) method shifted from Conventional Till Puddle Transplanted Rice (CTPTR) to CT Direct Seeded Rice (CTDSR) and Zero-Till DSR (ZTDSR) in paddy; and in wheat, from Conventional Till Wheat (CTW) to Zero Till Wheat (ZTW), with residue retention in rice (RRR) or in both rice and wheat (RRRW). Shift in CE methods led to change in Weed Seed Bank (WSB) dynamics and ultimately affected the weed management program. After five years of field trials, soil samples were drawn as per 2-factors factorial randomized block design. Factor-I comprised 4-CE methods, whereas factor-II consisted of 3-soil depths (0–10, 10–20 and 20–30 cm). Results showed CTPTR-CTW and ZTDSR-ZTW (RRRW) record the highest seed bank (SB) of grasses, sedges and BLWs as total weeds, in general; and predominant weeds like Echinochloa spp., Ammania baccifera, Commelina benghalensis and Digitaria sanguinalis, in particular. It also showed the higher species richness (DMg) and Shannon–Weaver (H’) indices. CTDSR-CTW and CTDSR-ZTW (RRR) show the lowest WSB and at par with Shannon–Weaver (H’) index; further, lowest species richness (DMg) under CTDSR-CTW. Species Evenness (J’) and Simpson index (λ) vary non-significantly with CE methods. Furthermore, 0–10 cm soil depth showed the highest SB of different category of total weed, predominant weeds as well as higher values of DMg, H’, and λ; whereas reverse trend was observed in Whittaker Statistic (βW). Interaction between CE methods and soil depth revealed most of WSB lying on the top layer in case of ZTDSR-ZTW (RRRW) and CTDSR-ZTW (RRR); while CTPTR-CTW showed almost uniform WSB distribution, and in case of CTDSR-CTW, a gradual decrease in WSB with soil depth.


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