Accepted manuscripts
Review
How are weeds named: A committee review of the WSSA composite list of names
- Theresa Reinhardt Piskáčková, Karla L Gage, Eugene P Law, Lauren M Schwartz-Lazaro, Joan M Campbell, Christine Taliga
-
- Published online by Cambridge University Press:
- 04 June 2024, pp. 1-31
-
- Article
- Export citation
-
Plant names carry a significant amount of information without providing a lengthy description. This is an efficient shorthand for scientists and stakeholders to communicate about a plant, but only when the name is based on a common understanding. It is standard to think of each plant having just two names, a common name and a scientific name, yet both names can be a source of confusion. There are often many common names that refer to the same plant, or a single common name that refers to multiple different species, and some plants are without a common name at all. Scientific names are based upon international standards; however, when there is not agreement in the taxonomy, two scientific names may be used to describe the same species. Weed scientists and practitioners can easily memorize multiple plant names and know that they refer to the same species, but when we consider global communication and far-reaching databases, it becomes very relevant to consider two sides of this shift: 1) A need for greater standardization (due to database management and risk of lost data from dropped cross-referencing) and 2) the loss of local heritage which provides useful meaning through various common names. In addition, weed scientists can be resistant to changing names that they learned or frequently use. The developments in online databases and reclassification of plant taxonomy by phylogenetic relationships have changed the accessibility and role of the list of standardized plant names compiled by the Weed Science Society of America (WSSA). As part of an attempt to reconcile WSSA and USDA common names for weedy plants, the WSSA Standardized Plant Names Committee recently concluded an extensive review of the Composite List of Weeds common names and had small changes approved to about 10% of the list of over 2800 distinct species.
Research Article
Impact of burial depth and root segment length on vegetative propagation of common milkweed (Asclepias syriaca)
- Rebecca S. Stup, Anna S. Westbrook, Antonio DiTommaso
-
- Published online by Cambridge University Press:
- 04 June 2024, pp. 1-15
-
- Article
- Export citation
-
Common milkweed (Asclepias syriaca L.) is widely planted as part of monarch butterfly (Danaus plexippus) conservation efforts. Vegetative propagation is an alternative to planting A. syriaca from seed, which offers advantages such as high emergence rates. The aim of this study was to determine the ideal planting depth and initial root segment length to vegetatively propagate A. syriaca. In a greenhouse trial with two runs, A. syriaca was grown from seed and then 3, 8 and 15-cm segments were harvested. These segments were then planted at depths of either 3, 8, or 15 cm. Planting depth did not impact A. syriaca growth, but an initial root segment length of 15 cm was associated with greater above- and belowground biomass and height in both runs of the experiment. Emergence rates were not impacted by either factor. Overall, A. syriaca was likely to establish regardless of the initial root segment length or planting depth, but plants grown from root segments of 15 cm were more vigorous than plants grown from shorter segments.
Effects of Bed Width and Crop Row Spacing on Barnyardgrass (Echinochloa crus-galli) Emergence and Seed Production in Furrow-Irrigated Rice
- Noah H. Reed, Thomas R. Butts, Jason K. Norsworthy, Jarrod T. Hardke, L. Tom Barber, Nick R. Bateman, Aurelie M. Poncet, Koffi B.J. Kouame
-
- Published online by Cambridge University Press:
- 20 May 2024, pp. 1-18
-
- Article
- Export citation
-
Furrow-irrigated rice (Oryza sativa L.) has become a popular option for rice production in Arkansas. Highly troublesome weeds like barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] are a major problem for producers in all rice production systems. Cultural tactics should become a priority to enhance crop growth and competitiveness. This research aimed to determine the effects of bed width (irrigation furrow spacing) and crop row spacing manipulation on E. crus-galli emergence and seed production in a furrow-irrigated rice system. Three bed widths (76-, 97-, and 152-cm) (whole plot factor) were used, and plots were drill-seeded in four crop row spacings (subplot factor) (13-, 19-, 25-, and 38-cm). The widest width of 152-cm had a slight increase in E. crus-galli density in the early rice life cycle but, by the end of the season, did not differ from the narrower bed widths. Conversely, a decrease in E. crus-galli seed production was observed as the bed width increased. Similar rice canopy coverage and yields occurred between all three bed widths. As for crop row spacing, as the width increased, E. crus-galli density also increased. The 13-cm crop row spacing had the lowest preflood E. crus-galli density, preharvest panicle count, and seed production. No effect of crop row spacing was observed on rice canopy coverage; however, the 13-cm crop row spacing produced the greatest rice yield. The 13-cm crop row spacing paired with the 152-cm bed width may be the optimum combination of ecological strategies in furrow-irrigated rice to reduce E. crus-galli seed production while maintaining rice growth and yield.
Investigating sexual and asexual modes of reproduction in Palmer Amaranth (Amaranthus palmeri)
- Hayley L. Brackenridge, Nikita Konstantinov, Lisa H. Han, Sarah B. Yakimowski
-
- Published online by Cambridge University Press:
- 20 May 2024, pp. 1-32
-
- Article
- Export citation
-
Palmer amaranth (Amaranthus palmeri S. Watson), a dioecious wind-pollinated plant, is one of the most troublesome crop weeds in the United States and is spreading northwards. The prodigious production of seed contributes to establishment of populations and spread across the landscape. Sexual reproduction via outcrossing is likely the primary mode of seed production for this dioecious plant. However, A. palmeri may also be capable of autonomous asexual seed production (apomixis), which could be beneficial during colonization. We conducted two studies of female isolation from pollen to investigate the propensity for autonomous seed production in 19 populations across eastern North America. In the first we observed low frequency seed production on many isolated females. Using flow cytometry of seed samples (FCSS) we primarily found patterns of ploidy consistent with sexual reproduction; no significant differences in ploidy between seeds produced on isolated females (putative apomicts) and non-isolated females (putatively sexual) were detected. We also investigated patterns of DNA content and found no evidence for polyploidy in 153 samples, which is often observed in apomictic species. The second female isolation trial utilized sex-specific molecular markers to identify and remove males prior to flowering, and we observed zero seed production. Overall, we did not detect evidence in support of apomixis in these populations of A. palmeri, suggesting that apomixis is unlikely to have played a role in the northward advance of this species in eastern North America. We also investigated whether there is variation between females and males in size and secondary reproductive traits. We found evidence for sexual dimorphism in three of six traits investigated: females are taller at senescence, produce longer secondary branches, and more axillary flowers than males. Differences in cost of reproduction and strategies for pollen release vs. pollen capture are likely factors shaping the evolution of sexual dimorphism in this wind-pollinated dioecious plant.
Review
Known and potential benefits of applying herbicides with glutathione S-transferase inhibitors and inducers – a review
- Pâmela Carvalho-Moore, Jason K. Norsworthy, Tristen H. Avent, Dean E. Riechers
-
- Published online by Cambridge University Press:
- 20 May 2024, pp. 1-43
-
- Article
- Export citation
-
Weed resistance to herbicides has increased exponentially during the past 30 to 40 years, consequently reducing the number of effective products available to control certain species and populations. Future efforts should target not only the discovery of new protein binding sites and the development of new molecules, but also the revival of old molecules with reduced efficacy due to widespread herbicide resistance. The addition of herbicide synergists that inhibit metabolic pathways or enhance intrinsic plant stress is a possible solution to ameliorate the negative effects caused by the lack of new herbicide chemistries. Glutathione S-transferase (GST) enzymes are involved with numerous herbicide detoxification reactions and plant stress responses. This review approaches the potential use of natural and synthetic GST-inhibitors to enhance herbicidal activity or induce crop safety to provide effective, sustainable weed management strategies in the future.
Research Article
Endothall and 2,4-D Activity in Milfoil Hybrid (Myriophyllum spicatum × M. sibiricum) when Applied Alone and in Combination
- Mirella F. Ortiz, Scott J. Nissen, Franck E. Dayan
-
- Published online by Cambridge University Press:
- 08 May 2024, pp. 1-16
-
- Article
- Export citation
-
Eurasian watermilfoil (Myriophyllum spicatum L.) is an invasive aquatic plant that can hybridize with the native Northern watermilfoil (Myriophyllum sibiricum Kom.). These milfoil hybrids (M. spicatum × M. sibiricum) are becoming more prevalent in many lakes where the invasive and the native milfoil co-occur. Hybrid plants are more vigorous than either parent with a faster growth rate and lower sensitivity to some herbicides. The aquatic herbicides, endothall and 2,4-D, provide two effective modes of action (MOA) for management of the hybrids. For more than a decade, these two herbicides have been used in combination as an effective control option and a resistance management strategy. How this combination impacts herbicide movement and efficacy is unknown. Therefore, the objective of this research was to determine the activity of endothall and 2,4-D combined compared to activity applied alone. Absorption and translocation of endothall, 2,4-D and the combination was determined in hybrid plants over a 96-h time course. Endothall bioaccumulation was not impacted when these herbicides were applied in combination; however, 2,4-D accumulation increased by 80%, relative to when 2,4-D was applied alone. Endothall translocation from shoots to roots decreased by almost 50% when applied in combination with 2,4-D (alone = 16.7% ± 2.6; combination = 9.2% ± 1.2). Shoot-to-root translocation of 2,4-D also decreased when the two herbicides were applied in combination (24.8% ± 2.6 when applied alone to only 3.93% ± 0.4 when in the presence of endothall). This research demonstrates that combining herbicides can significantly impact herbicide activity in plants. Future research is needed to determine if this reduced translocation negatively impacts operational effectiveness when these herbicides applied in combination.