Day and night temperature effects on vegetative growth of Erodium Cicutarium

The vegetative growth response of Erodium cicutarium (L.) ?Her. ex Ait. to various day:night temperature regimes was studied under controlled environment conditions. Dry matter production was greatest with day temperatures of 18 to 34^C combined with night temperatures of 12 to 18^C. A high night temperature of 24^C was very detrimental, reducing dry matter production to 15 to 25% of that attained at 12^C. The optimum mean daily temperature for growth of E. cicutarium is predicted to be in the range 17 to 20^C. Little growth is predicted at mean daily temperatures below 5^C and above 30^C. Partitioning of biomass in leaves, stems and roots was markedly affected by day and night temperatures. Stem weight ratio was greatest at day temperatures of 18 to 34^C and night temperatures of 18 to 24^C. Maximum leaf weight ratio occurred at day and night temperatures of 10 to 18^C. Root biomass was little affected by day temperatures, but was greatest at a night temperature of 12^C, declining substantially as night temperature increased from 12 to 24^C. Results are discussed in terms of the potential for E. cicutarium to become an increasingly troublesome weed in crops of the Canadian prairies and in terms of possible management strategies for its control.     

Growth characteristics of spring barley and selected weeds. II. Effect of temperature and irradiance in growth chambers

As a part of a broader study, two experiments were carried out in growth chambers with three day/night temperature regimes (10/7, 20/14 and 30/21^C) studying growth characteristics of individual seedlings over a four-week period. Experiment 1 was performed with spring barley (Hordeum vulgare L.), Galeopsis tetrahit L., and Viola Arvensis Murray. Experiment 2, with three irradiance levels at 20/14^C, and one irradiance level at the other temperatures, was performed with spring barley, V. arvensis, Chenopodium album L., Brassica rapa L. sspoleifera (DC.) Metzger, and Stellaria media (L.) Vill. Leaf area, dry weight, relative growth rate, net assimilation rate, and net photosynthetic rate generally showed an optimum at 20/14^C. Increasing irradiance resulted in a decreased specific leaf area. Expressed as fraction of shoot dry weight, green leaves decreased and stems, flowers, and yellow leaves increased with increased time, irradiance, and temperature. At all temperatures, barley, B. rapa and G. tetrahit had the largest dry weights, but at 20/14^C. C album and S. media and at 30/21^C C. album also had large values. Differences in dry weight between species correlated more to morphological features than to assimilation rate.     

Resistance to paraquat in Hordeum glaucum is temperature dependent and not associated with enhanced apoplasmic binding

Response to paraquat was investigated in two Hordeum glaucum Steud. (wall barley) biotypes grown at warm (30^C) and cool (15^C) temperatures. Paraquat-resistant (R) plants were nearly seven-fold more tolerant when grown at 15^C than when grown at 3CPC. In contrast, there was a tendency for susceptible (S) plants to be more tolerant when grown at the higher temperature. The difference in response between the two biotypes grown at 30^ and 15^C increased from 3- to >40-fold. Forty-eight hours after foliar application, 62% less radiolabelled paraquat had translocated basipetally in the R compared with the S biotype. In addition, 26% more herbicide was retained within the treated zone of R compared with S plants. Thus, paraquat movement was restricted in the R biotype. It has been postulated that reduced mobility of the herbicide in the R plants is due to enhanced apoplasmic binding. In this study, paraquat binding to the cell walls and its release into the external solution was investigated in roots of R and S biotypes of H. glaucum grown under warm or cool conditions. No significant differences between the two biotypes were measured at either growth temperature. We propose that the mechanism of resistance to paraquat may involve a temperature-dependent alteration in symplasmic transport of the herbicide.     

Effect of salt stress on the structure and carbon flow mechanism in a noxious weed Parthenium hysterophorus L.

Effect of salt stress on structural changes, ion uptake, rate of photosynthesis and path of carbon in the exotic weed Parthenium hysterophorus have been investigated. Photosynthetic leaf area, chlorophyll and carbon assimilation rates were adversely affected by salt stress. Increased Na⁺ uptake caused decrease in K⁺ and Ca²⁺ absorption. Originally a C₃ plant, P. hysterophorus appears to form aspartate as a primary product of photosynthesis when exposed to NaCl. The stimulation of PEP carboxylase activity also occurred due to salt stress. Excessive accumulation of malate during steady state of photosynthesis was possibly due to inhibition of malic enzyme. It appears that although the plant switches over to an ‘aspartate producer’ when exposed to salt, further utilization of photosynthetically assimilated carbon is through malate. Being a weed, the plant appears to be highly adaptive to stress conditions.     

Crop–weed competition rather than temperature limits the population establishment of two annual C4 weeds at the edge of their northern range

Climate change is predicted to affect range expansion of harmful C₄ weeds into the boreal region, given that they are able to successfully colonise both C₃ and C₄ crops. We studied the impact of a 3°C elevation in temperature on the establishment and maintenance of populations of two annual C₄ weeds (Amaranthus retroflexus and Echinochloa crus‐galli) with and without a competing C₃ (barley) or C₄ (maize) crop. Data obtained from field and glasshouse experiments were modelled using a periodic matrix population model. Competition of a weed with a crop appeared to be a more important factor for limiting the maintenance of weed populations than elevation in temperature, as neither of the weed species was able to maintain populations in competition with crops. Even an increase in the frequency of warm years did not result in viable weed populations establishing. However, A. retroflexus was able to form persistent populations in competition with maize when released from competition every fifth year. Simulations parameterised from glasshouse data predicted that both weed species would persist without competition in the current climate, whereas simulations parameterised from field data suggested only A. retroflexus to be able to persist. These results demonstrate that competition affects the range expansion of arable weed species more than elevation in temperature, necessitating the inclusion of crop–weed interactions in models of range shifts as a consequence of climate change.     

The effect of temperature on sprouting and early establishment of Cynodon dactylon

Bud-sprouting dynamics, sprouting base temperature and reserve mobilization of rhizomes and stolons of Cynodon dactylon (L.) Pers. were characterized in a laboratory experiment under dark conditions. In addition, the dynamics of sprout emergence were determined during 2 years under field conditions. In the laboratory experiment, buds from the vegetative structures did not sprout at temperatures below 7^C. The rate of sprouting increased with temperature within the range 11–33^C, and a base temperature of 7.71^C was determined for bud sprouting of rhizome and stolons of the weed. An exponential model is proposed relating the percentage of sprout emergence in the field to accumulated thermal units, calculated as the sum of the daily mean air temperature above the base temperature of bud sprouting. This model satisfactorily predicted the dynamics of C. dactylon sprout emergence in sunflower (Helianthus annuus L.) crop fields. The efficiency of carbohydrate reserve use during sprout growth was highly dependent on temperature and type of vegetative structure The efficiency was maximum at 20^C and was higher for rhizomes than for stolons. The main factors influencing bud sprouting and early weed establishment are discussed.     

Evaluation of three empirical models depicting Ambrosia artemisiifolia competition in white bean

The performance of three empirical models describing white bean yield loss (Y_L) from common ragweed competition was compared using field experiments from Staffa and Woodstock, both in Ontario, Canada, in 1991 and 1992. One model was based upon both weed density and relative time of emergence. The other two models described yield loss as a function of weed leaf area relative to the crop. The model based on both weed density and relative time of emergence best described the data sets. The predicted maximum yield loss (A) and the parameter for relative time of weed emergence (C) varied across locations and years whereas the yield loss at low weed density (I) was relatively more consistent across locations and years. Use of thermal time (base temperature=10^oC) rather than calendar days did not change the overall fit of the model, but reduced the value of the parameter for the relative time of weed emergence (C). The two parameter leaf area model accounting for maximum yield loss (m) gave a better fit to the data compared with the one parameter model. The relative damage coefficient (q) varied with time of leaf area assessment, location and year. Values of q calculated from relative leaf area growth rates of the crop and weed were similar to observed values. The relationship between q and accumulated thermal time was linear but varied with location and year. As management tools, models based upon relative leaf area have advantages over models based on density and relative time of emergence since the level of weed infestation needs only to be assessed once, whereas density and emergence time require frequent observations. The ability to assess accurately and quickly both the crop and weed leaf area, however, may limit the practical application of models based on leaf area. The inability of empirical models to account for year–to–year variation in environmental conditions was observed.     

Ecophysiological factors contributing to the invasion of Panicum maximum into native Miscanthus sinensis grassland in Taiwan

Panicum maximum (guinea grass), a native grass of Africa, has invaded and displaced the native Miscanthus sinensis grassland at Dadu terrace in central Taiwan. The Dadu terrace has distinct wet and dry seasons and is prone to fire during the dry seasons. We compared photosynthesis and growth, as well as the growth response to two water treatments, between P. maximum and M. sinensis plants to understand ecophysiological factors contributing to the successful invasion of the grass. In comparison with M. sinensis, P. maximum had a significantly higher photosynthetic rate, larger specific leaf area and a higher leaf area/total biomass ratio, and thus grew faster and higher, and accumulated more biomass under well‐watered conditions. The growth of P. maximum was more susceptible than M. sinensis to drought stress. Faster growth of seedlings and more biomass accumulation of mature plants would give P. maximum a highly competitive advantage over M. sinensis for resource acquisition in the Dadu terrace during the wet season, which might contribute to the successful invasion of P. maximum into the grassland of M. sinensis.     

The influence of temperature and photoperiod on growth and development of Parthenium hysterophorus L.

Germination, growth and flowering were investigated in Parthenium hysterophoms (Asteraceae), a species introduced to Australia and at present occurring as a weed in central Queensland. Combinations of day/night temperature regimes from 15/4 to 36/31 and day length of 10, 13 and 16 h in controlled conditions were examined to find the effects of any environmental restraints to growth and development. Results showed that individuals are able to germinate, grow and flower over a wide range of temperatures and photoperiods and established plants can survive at least one mild frost of — 2. We conclude that the potential distribution of P. hyslerophorus in Australia is much wider than at present. Future distribution of the species may be limited seasonally by the inability of seed to germinate in soils of low water potential and by the inability of seedlings to establish and grow at low light intensities.     

Vertical distribution, size and composition of the weed seedbank under various tillage and herbicide treatments in a sequence of industrial crops

Investigations were conducted during the 2003, 2004 and 2005 growing seasons in northern Greece to evaluate effects of tillage regime (mouldboard plough, chisel plough and rotary tiller), cropping sequence (continuous cotton, cotton–sugar beet rotation and continuous tobacco) and herbicide treatment on weed seedbank dynamics. Amaranthus spp. and Portulaca oleracea were the most abundant species, ranging from 76% to 89% of total weed seeds found in 0–15 and 15–30 cm soil depths during the 3 years. With the mouldboard plough, 48% and 52% of the weed seedbank was found in the 0–15 and 15–30 cm soil horizons, while approximately 60% was concentrated in the upper 15 cm soil horizon for chisel plough and rotary tillage. Mouldboard ploughing significantly buried more Echinochloa crus‐galli seeds in the 15–30 cm soil horizon compared with the other tillage regimes. Total seedbank (0–30 cm) of P. oleracea was significantly reduced in cotton–sugar beet rotation compared with cotton and tobacco monocultures, while the opposite occurred for E. crus‐galli. Total seed densities of most annual broad‐leaved weed species (Amaranthus spp., P. oleracea, Solanum nigrum) and E. crus‐galli were lower in herbicide treated than in untreated plots. The results suggest that in light textured soils, conventional tillage with herbicide use gradually reduces seed density of small seeded weed species in the top 15 cm over several years. In contrast, crop rotation with the early established sugar beet favours spring‐germinating grass weed species, but also prevents establishment of summer‐germinating weed species by the early developing crop canopy.     

Spray treatments combined with climate modification for the management of Leveillula taurica in sweet pepper

The effects of several spray and climate treatments on Leveillula taurica were tested under controlled and commercial greenhouse conditions either alone or combined with a climate treatment. Ampelomyces quisqualis AQ10 inhibited the germination of conidia on leaves, but not on glass. Trichoderma harzianum T39 inhibited germination on both surfaces. Neither the examined biological control agents (BCAs) nor the two tested mineral oils (AddQ and JMS Stylet-Oil) affected the viability of conidia. Sulphur drastically limited the germination and viability of L. taurica. In experiments at 15–25°C, AQ10 alone reduced hyphal leaf colonisation at 25°C. T. harzianum T39 significantly reduced leaf colonisation at all temperatures but significantly reduced disease only at 20–25°C. The oils significantly reduced leaf colonisation and sulphur reduced both leaf colonisation and disease at all temperatures. Results were confirmed in an experimental greenhouse. In a field experiment, azoxystrobin, polyoxin AL, neem extract, and T39 were effective; sulphur was superior to them. Under severe epidemic conditions the disease had a negative impact on yield; late fungicide treatments at spring-time were found unnecessary. Chemical sprays applied in alternation was compared with the ‘friendly’ spray regime (alternation of Heliosoufre, T. harzianum T39 + JMS Stylet oil, A. quisqualis AQ10+AddQ oil and Neemgard) in two climates i.e. (i.) day warm climate and (ii.) regular (cool) day climate regimes. In the warm climate, there was no significant difference in the performance of the ‘friendly’ spray regime and the chemical spray regime. However, in the cooler climate, the ‘friendly’ spray programme was not as effective as the chemical spray programme. It was concluded that a change in the greenhouse climate may affect the development of powdery mildew and, at the same time, promote the activity of BCAs and render a pathogen more vulnerable to these control agents, allowing for better disease suppression.     

Germination behaviour in seeds of Diplotaxis erucoides and D. virgata

The seed germination behaviour of four populations each of Diplotaxis erucoides (L.) DC. and D. virgata (Cav.) DC, two weedy Brassicaceae species widely distributed in the Mediterranean region, was studied under controlled light, temperature and moisture conditions. Germination rates in D. virgata were generally higher at alternating (25/15^C) and low (15^C) temperatures, whereas in D. erucoides optimal germination rates were achieved at higher temperatures (25^C). No correlation between seed weight and germination was found in either species. In D. virgata, the geographic origin of the seed had an important effect on germination percentage. Great germination variability was found among the populations and even among seeds belonging to the same population. In this species, the application of gibberellic acid stimulated germination, especially in the populations with higher dormancy levels. Dormancy was found in mature D. virgata seeds but not in those of D. erucoides. In both species, germination percentages decreased after a certain period of storage at low temperatures. This period varied depending on the species and the population considered.     

Effects of phosphorus and light intensity on the growth and competition of the two weed species,Veronica persica and Chorispora tenella

Veronica persica Poir. (Persian speedwell) is an invasive alien weed species in the upland soils throughout China. Its dominance in weed flora could be alleviated by Chorispora tenella (Pall.) (tender chorispora) in P‐poor soils and in an intense light environment. Here, three experiments in growth chambers were carried out in order to explore the effect of P and light intensity on the growth and competition of V. persica and C. tenella, the pH value in their rhizospheres, and the kinetic parameters (K_m and V_max) of the H₂PO₄^‐ uptake by the two weed species. The ANOVA results showed that the light intensity and P level in the soil obviously influenced the growth of the two weed species. However, the effect of the P level in the soil was greater for V. persica and the effect of the light intensity was greater for C. tenella. The restriction of the growth of V. persica by a low P level in the soil was much more than that of C. tenella, but it was reversed in the two species in relation to a low light intensity. In addition, the pH was lower in the rhizosphere of C. tenella after the P‐deficient treatment and there was a lower K_m in the uptake of H₂PO₄^‐ than for V. persica, suggesting that C. tenella could adapt to a low‐P environment more easily. In conclusion, C. tenella growing together with V. persica had a competitive advantage under high‐light‐intensity and low‐P‐level conditions, but it lost its advantage with an increase in P fertilization and a decrease in light intensity.     

Weed suppressiveness of paving joint filling materials under diverging water regimes

Since 2015, chemical weed control on public pavements in Flanders has been banned. This necessitates alternative weed control strategies. In this study, growth chamber experiments evaluated the weed suppressive ability of different joint filling materials under various water regimes. The tested materials comprised five unbound standard fillers (white quartz sand, sea sand, limestone 0/2 mm, limestone 2/6.3 mm and porphyry 2/6.3 mm) and two innovative materials (Dansand^® and Eco Fugensand^®). Their weed suppressiveness was tested in pure and organically polluted states. Germination and biomass accumulation of two weed species that are abundantly found on public pavements (Lolium perenne and Taraxacum officinale) were investigated. Germination and biomass accumulation were lowest in both innovative materials, irrespective of organic contamination level, plant species and water regime. Weed growth in the standard materials was affected by plant species and water regime. Monthly biomass accumulation increased with increasing monthly water supply and number of irrigation days. Furthermore, the materials best capable of reducing weed growth, under all water regimes, even when organically polluted, were the innovative materials and sea sand. The results of this study show that the implemented water regime can influence weed suppressiveness (absolute as well as relative) of a joint filler. Hence, to fully assess weed suppressive ability, commercially launched joint fillers should be tested under diverging water regimes.     

Using a selectivity index to evaluate logarithmic spraying in grass seed crops

BACKGROUND: Grass seed crops are minor crops that cannot support the development of selective herbicides for grass weed control in grass seed crops. An option is to screen for selective herbicides with the use of logarithmic spraying technology. The aim of this paper is to assess selectivity of various herbicides in grass seed crops by using dose–response curves. RESULTS: Six grass species were subjected to logarithmic spraying with 11 herbicides and with Poa pratensis L. as a weed. The ratio between the doses that caused 10% of damage to the crop and 90% of damage to the weed was used as a selectivity index. Compounds with selectivity indices above 2 can be safely used in a crop. The two ACCase herbicides clodinafop‐propargyl and fenoxaprop‐P‐ethyl and a mixture of the two ALS herbicides mesosulfuron and iodosulfuron could be used selectively to control P. pratensis in Festuca rubra L., although the selectivity indices in no instances were greater than the desired 2.0. CONCLUSION: The logarithmic sprayer can be a rapid screening tool for identifying compounds with favourable selectivity indices. Good experimental design is needed to alleviate rates being systematically distributed and confounded with growth rate and soil fertility gradients. Copyright © 2009 Society of Chemical Industry     

Differential translocation of paraquat in paraquat-resistant populations of Hordeum leporinum

Two populations of Hordeum leporinum have evolved resistance to paraquat within a small area in central Tasmania, Australia. One population (THL1) was more than 80-fold resistant to paraquat when treated in winter, compared with a susceptible population (THL4) collected nearby, whereas the other population (THL2) was only 19-fold resistant. Translocation of paraquat was examined in all three populations at warm and cool temperature regimes. Herbicide was applied to a basal section of the second leaf of plants kept in the dark and translocation measured after 16 h of dark and during a subsequent light period. Paraquat absorption into the treated leaf was uniformly high in susceptible and resistant populations, with >93% of the applied herbicide absorbed within 16 h in the dark at both temperatures. Translocation of paraquat out of the treated leaf was low in the dark, with <4% of the herbicide translocated to the remainder of the plant. More herbicide was translocated out of the treated leaves in susceptible plants in the dark, compared with resistant plants at both temperature regimes and more paraquat was translocated at warmer temperatures. Extensive basipetal translocation of paraquat to the rest of the plant occurred in susceptible plants following exposure of the treated plants to light. However, basipetal translocation was much reduced in resistant plants in the light and corresponded to the degree of resistance. Resistance to paraquat in H. leporinum is the result of reduced translocation of paraquat out of the treated leaves.     

Reducing tillage intensity affects the cumulative emergence dynamics of annual grass weeds in winter cereals

Annual grass weeds such as Apera spica‐venti and Vulpia myuros are promoted in non‐inversion tillage systems and winter cereal‐based crop rotations. Unsatisfactory weed control in these conditions is often associated with a poor understanding of the emergence pattern of these weed species. The aim of this study was to investigate, understand and model the cumulative emergence patterns of A. spica‐venti, V. myuros and Poa annua in winter cereals grown in three primary tillage regimes: (i) mouldboard ploughing, (ii) pre‐sowing tine cultivation to 8–10 cm soil depth and (iii) direct drilling. Direct drilling delayed the cumulative emergence of A. spica‐venti and V. myuros (counted together) in contrast with ploughing, while the emergence pattern of P. annua was unaffected by the type of tillage system. The total density of emerged weed seedlings varied between the tillage systems and years with a higher total emergence seen under direct drilling, followed by pre‐sowing tine cultivation and ploughing. The emergence patterns of all species were differently influenced by the tillage systems, suggesting that under direct drilling, in which these species occur simultaneously, management interventions should first and foremost consider that A. spica‐venti and V. myuros emerge over a longer period to avoid control failures.     

Weed control in wheat with pyroxasulfone and its combinations with other herbicides

Field and pot investigations were conducted to determine the effectiveness of pyroxasulfone alone and its combinations with other herbicides against diverse weed flora of wheat (Triticum aestivum L.) including multiple herbicide-resistant (MHR) littleseed canarygrass (Phalaris minor Retz.). Applications of pyroxasulfone 100–127.5 g/ha as pre-emergence (PE) or early post-emergence (EPOE) @ 63.75 g/ha at 21–23 days after sowing (1 day before irrigation) were highly effective for control of grass weeds namely P. minor and wild oat (Avena ludoviciana Dur.). It was poor for control of broad-leaved weeds (Medicago denticulata Willd. and Rumex dentatus L.). However, pyroxasulfone in tank-mix combination with metsulfuron 4 g/ha, triasulfuron 20 g/ha, and pyroxsulam 18 g/ha effectively controlled (96.5%–99.8%) the diverse weed flora and improved the wheat grain yield (69.5%–285.9%) over untreated weedy control. Also, the pre-mix of pyroxasulfone + pendimethalin applied as PE was superior to either of these applied alone for weed control and grain yield. Pyroxasulfone 100–127.5 g/ha had yield gain of 119.6%–125.4% and 10.1%–26% over untreated control and pendimethalin 800–1250 g/ha, respectively. In pot studies, straw burnt ash drastically reduced the pyroxasulfone efficacy against P. minor and A. ludoviciana. Pyroxasulfone was also effective in pot studies for control of MHR P. minor having resistance against acetyl-coA carboxylase (ACCase), acetolactate synthase (ALS), and photosynthesis at the photosystem-II site-A (PS-II) inhibitor herbicides (clodinafop, sulfosulfuron, and isoproturon, respectively). The studies indicate that pyroxasulfone as PE or EPOE can be an alternative grass weed control herbicide in wheat in particular for the control of MHR P. minor.     

Modelling Chloris virgata germination and emergence under different temperature and light quality conditions

Chloris virgata is a problematic weed around the world. Prediction of weed germination rates could be a useful strategy to optimise timing of weed control actions. We studied the germination and emergence of C. virgata collected seeds under different after-ripening treatments and different exhumation dates after seed dispersal, to estimate seed dormancy level and predict weed emergence dynamics under field conditions. Three experiments were conducted under controlled conditions to determine base, optimum and maximum germination temperatures (T_b, T_o and T_m respectively) and comprised: (a) exposure of seeds to gradually increasing and decreasing temperatures between 5 and 35°C; (b) exposure of seeds to different constant temperatures; and (c) exposure of seeds to different light quality conditions (red – far red ratio) and temperature regimes (constant and alternating temperatures). To explore genuine environmental conditions, a field experiment was performed to determine weed emergence under different shading levels. Finally, with the data obtained, a thermal time model for dormancy release was used to predict C. virgata seedling emergence in the Argentine Pampas region. Seeds after-ripened in cold and wet conditions and constant 25°C showed the highest germination percentages. The values of T_b (7°C), T_o (28°C) and T_m (40°C) remained constant at all exhumation dates. Neither light quality nor thermal regime modified the final germination percentages. However, shading delayed seedling emergence under field conditions, even when it was adjusted by thermal time. These results may allow predicting C. virgata emergence in temperate regions and help to improve weed control in integrated weed management strategies.     

Vulpia myuros,an increasing threat for agriculture

Vulpia myuros is an annual grass species of Mediterranean origin, which has achieved a global distribution. It is a fast‐growing species, with high colonisation and competitive abilities. This species is considered an invasive weed in most countries where it has been introduced, with highly negative economic impact where it now dominates. It is increasingly found to be a problematic weed in winter cereals, especially in no‐till and reduced tillage systems, across Europe, United States and Australia. Seeds of V. myuros have reduced germination potential when buried. However, where tillage interventions are reduced, ideal conditions for V. myuros are created. Minimum and no tillage practices are increasing worldwide, with a concomitant increase in the spread and abundance of V. myuros. Effectiveness of herbicides is mostly suboptimal, in particular for well‐established populations forming dense swards, even though no herbicide resistance has yet been identified. An integrated management approach, increasing crop diversification combined with management adaptations, possibly including herbicides is suggested as an effective control strategy. Despite increasing research on V. myuros, more information is needed to optimise the management of this weed. Based on the species’ Mediterranean origins and adaptation to warm and dry environments, an increase of its global importance may be expected with climate changes. It is thus paramount to increase the awareness around this species, improve its identification in the field and monitor its spread before it becomes a concern of similar magnitude to grass weeds like Alopecurus myosuroides or Lolium rigidum.