View Rensis Branches Differently to C

122 Plant Protection Quarterly Vol.22(4) 2007 Conyza sumatrensis can grow up to 2 m high. It is often confused with C. bonariensis because of the similar size of the fl ower head (Wilson et al. 1995). Conyza sumat- Review rensis branches differently to C. bonariensis, with lateral branches near the top and not overtopping the central stem, forming a pyramidal infl orescence (Everett 1992, Wilson et al. 1995). It also differs from C. bonariensis in that there are no long hairs The biology of Australian weeds near the apex (Auld and Medd 1987). Leaves of C. sumatrensis are usually wider 49. Conyza bonariensis (L.) Cronquist (5–20 mm) than those of C. bonariensis (6 mm) (Sida 2003). Hanwen Wu, E.H. Graham Centre for Agricultural Innovation, Wagga Wagga Agricultural Institute, Wagga Wagga, New South Wales 2650, Australia. History Conyza bonariensis is generally believed to be native to South America (Michael 1977, Everett 1992, Wilson et al. 1995, Prieur- Richard et al. 2000). It was fi rst described Name mm diam. Ray fl orets 50–200 or more per from Argentina (Michael 1977). Conyza Conyza bonariensis (L.) Cronquist is a spe- head; involucre urceolate, bracts in 3 or 4 bonariensis could have been introduced cies of the Asteraceae family. Synonyms series, linear, acute, hirsute, subequal or to eastern and southeast Asia and to Aus- include C. albida Willd. ex Spreng., C. outer ones shorter, inner bracts 3–4 mm tralia and New Zealand from both Europe ambigua DC, C. bonariensis var. leiotheca long, outer bracts ca. 2 mm long. Outer and America. A number of specimens of (S.F.Black) Cuatrec., C. bonariensis var. mi- fl orets numerous, in 6–7 marginal rows, C. bonariensis collected in Australia were crocephala (Cabrera) Cabrera, C. fl oribunda corolla white, fi liform-tubular, 2–2.2 mm dated back in the 1840s (Michael 1977). Co- Kunth, Conyzella linifolia Willd., Conyza long, ligule minute, obscure; style ca. 2.5 nyza bonariensis may have been introduced linifolia Willd., Erigeron albidus (Willd. ex mm long, slightly longer than pappus. accidentally to South Australia (Burry and Spreng.) A.Gray, Erigeron ambiguus (DC.) Central disc fl orets 12–20, corolla 3–3.5 Kloot 1982). It was widespread in the Ad- Sch.Bip. E. bonariensis L., Erigeron bonarien- mm long; upper part narrowly cylindric, elaide area and around other settlements sis var. leiothecus S.F.Black, E. bonariensis longer than lower fi liform part, 5-lobed, at the time of the fi rst botanical collections var. microcephalus Cabrera, E. crispus Pour- yellowish. Achenes oblong, pubescent, ca. in 1847. ret, E. fl oribundus (Kunth) Sch.Bip., E. lini- 0.5–1 mm long, 0.2–0.3 mm thick, com- folius Willd., Leptilon bonariensis (L.) Small, pressed, ribbed on both side, pale umber; Distribution Leptilon linifolium (Willd.) Small, Marsea pappus 1-seriate, united at base, barbel- Conyza bonariensis is a cosmopolitan weed. bonariensis (L.) V.M.Babillo (Cronquist late, white to pink bristles c. 3 mm long. It infests arable land, orchard, vineyard, 1943, Danin 1976, Michael 1977, Wagner Flowers throughout year (Cunningham forest, roadsides, abandoned fi elds, as well et al. 1999, Maia 2002, Randall 2002, Sida et al. 1981, Everett 1992, Peng et al. 1998, as industrial sites (Burry and Kloot 1982, 2003, Pruski 2006). Wagner et al. 1999). Prieur-Richard et al. 2000, Heap 2007). It is Common names include hairy fl eabane, Conyza bonariensis is a hexaploid spe- naturalized in warm areas throughout the fl ax-leaf fl eabane, fl eabane, wavy-leaved cies (allopolyploid), with a chromosome world, in Europe mainly in the Mediterra- fl eabane, asthma weed and Argentiinan- number of 2n = 54 (Razaq et al. 1994, Ur- nean Basin (Terzioğlu and Anşin 2001, Sida koiransilmä (Roy et al. 1998, Randall 2002). dampilleta et al. 2005). In Australia, there 2003). It is more thermophilous than its It is commonly known in Brazil as acatóia, are six other Conyza species, C. leucantha, close relative C. sumatrensis. In temperate arnicão, buva, capetiçoba, capiçoba, cati- C. primulifolia (previously named C. chilen- Europe, e.g. in the British Isles, it persists çoba, ervalanceta, lagarteira, margaridin- sis), C. sumatrensis (previously named C. only in big cities and is absent from rural ha-do-campo, rabo-de-foguete, rabo-de- albida), C. canadensis var. canadensis, C. par- areas due to their colder climate (Wurzell raposa, rabo-de-rojão, salpeixinho, and va, and C. bilbaoana (Everett 1992, Randall 1994). Conyza bonariensis is rarely found voadeira (Maia 2002, Barbosa et al. 2005). 2002). C. bonariensis is the most widespread in Central Europe, and occurs there only introduced species in Australia, followed temporarily (Sida 2003). Description (Taxonomy) by C. canadensis and C. sumatrensis (Burry It is widespread across all States in Aus- Annual or biennial herb to 1 m high, ro- and Kloot 1982, Lazarides et al. 1997, Rich- tralia (Michael 1977, Cunningham et al. bust, erect, grey-hispid; stems usually ardson et al. 2006). 1981, Everett 1992). The current distribu- unbranched below inflorescences, of- There has been confusion amongst the tion of C. bonariensis in Australia is shown ten branched near base, lateral branches three most widely distributed Conyza spe- in Figure 1. regularly overtopping main axis, dense- cies. Both C. canadensis and C. sumatrensis Conyza bonariensis is widely distributed ly hirsute with spreading septate hairs. are annuals. The former has a chromosome in the northern grains region of Australia, Leaves hispid with short antrorse hairs number of 2n = 18, while the latter has 2n infesting both winter and summer crops and with longer spreading septate hairs; = 54 (Thebaud and Abbott 1995). Conyza such as wheat, chickpea, cotton and sor- leaves densely arranged, usually greyish- bonariensis has the narrowest leaves at the ghum (Wu and Walker 2004). It is one of green, basal leaves linear, oblong, or nar- rosette stage when compared to other Co- the most diffi cult weeds to control in mini- row-oblanceolate, 4–9 cm long, 5–15 mm nyza species (Thebaud and Abbott 1995). mum tillage farming systems (Somervaille wide, margins toothed, sometimes teeth Conyza bonariensis has a more compact stat- and McLennan 2003). It is a common weed obscure; leaves becoming progressively ure, with many short branches and bear- of horticulture in Perth and also common smaller, 3–6 cm long and 5–10 mm wide, ing large capitula, while C. canadensis is es- on disturbed sites, such as roadsides, from oblong to linear, entire. Infl orescence a sentially a single-stemmed taxon with few Perth to Esperance. It has also been found pyramidal or corymbiform panicle; head long branches and with small and elongat- near Kununurra (Hussey et al. 1997). many, hemispherical, 5–6 mm long, 8–12 ed capitula (Thebaud and Abbott 1995). Plant Protection Quarterly Vol.22(4) 2007 123 Habitat Climatic requirements Conyza bonariensis is distributed widely throughout the warmer regions of the world (Terzioğlu and Anşin 2001, Sida 2003). The broad geographical distribution of C. bonariensis in Australia suggests that there is no specifi c climatic requirement. It is a pantropical weed, spreading into warm-temperate regions (GRIN 2007).

Substratum Conyza bonariensis can occur in most soil types and plant communities, particularly in areas of disturbed soil and in and around gardens (Cunningham et al. 1981). It is more common on lighter soils, although it can sometimes be found on heavy textured soils (Wu et al. 2007). It is also commonly found in irrigation channels. Seed burial studies demonstrated Figure 1. Geographical distribution based no C. bonariensis emergence in pots con- on the 684 records deposited in Australia’s taining a heavy textured soil (vertosol) Virtual Herbarium (AVH 2007). under fi eld conditions in south-eastern Queensland. In laboratory studies, C. bonariensis seeds readily germinated within compared with the conven- two days at 20°C in continuous light, tional tillage systems. (a) suggesting that in a fi eld situation, C. bonariensis seeds would germinate after an Growth and development adequate rainfall event in either autumn Morphology or spring. Similarly, Davies (1999) report- The morphological developed that seedling emergence occurred three ment of C. bonariensis has been days after sowing. However, seeds germi- described in great detail by Fi- nating on the heavy vertosol soil in south- not et al. (1996). The expanded eastern Queensland could encounter a dis- cotyledons are oblong to oval- ruption of moisture supply from deeper elliptical, 7 mm in length and in the soil profi le due to the self-mulching 4 mm in width. The fi rst pair (surface cracking) characteristics of this of expanded leaves is 1.4–1.5 soil type, resulting in a failure of further cm long and 0.7–0.8 cm wide, emergence (Wu et al. 2007). The impact of whole margin, rounded in the soil types on C. bonariensis emergence re- apex and obtuse in the base. quires further investigation. The second to fi fth leaves are of oval/egg shape, 4.3–5 cm in (b) Plant associations length by 1–1.2 cm in width. Conyza bonariensis occurs in most habitats Conyza bonariensis seedlings are throughout Australia and is common in shown in Figure 2. urban areas (Auld and Medd 1987). It is Conyza bonariensis produces a weed of disturbed areas and wasteland basal rosettes prior to bolting (Everett 1992). It is widespread and often and fl owering (Thebaud and a common component of pasture, particu- Abbott 1995). Seedling emer- larly in areas which are neglected or where gence was observed three days ground cover is poor (Cunningham et al. after sowing. After 30 days, 1981). Conyza bonariensis is an opportunis- plants showed four true leaves tic invader of subhumid, subtropical pas- in rosette disposition (Davies tures of improved fertility status resulting 1999). Conyza bonariensis seed- from legume establishment (Tothill and ling growth is very slow, and Berry 1981). Prieur-Richard et al. (2000) the rosette stage relatively pro- Figure 2. Young Conyza bonariensis seedlings reported that a high concentration of soil longed, even under the opti- at cotyledon (a) and rosette stages (b). nitrate associated with legumes is a key mal thermoperiods of 27/22°C factor for the increased vegetative growth (Zinzolker et al. 1985). Active and reproductive effort of C. bonariensis. growth commences in spring or early Abbott 1995). At the fl owering stage, C. The abundance of C. bonariensis is in- summer with plants producing, over a bonariensis plants have an average dry creasing in no-till farming systems, possi- long period, a mass of light fl uffy seeds weight of 90.3 g per plant. The ratio of bly due to a better environment for germi- which are readily dispersed by the wind leaf to stem dry weight at fl owering is 1:1 nation and seedling survival as a result of (Cunningham et al. 1981). (Davies 1999). stubble retention (Wu et al. 2007). Surface It takes 11 weeks for C. bonariensis to Conyza bonariensis has re-sprouting moisture conditions are likely to stay fa- reach the bolting stage. Conyza bonarien- characteristics (Figure 3). There were vourable for germination and emergence sis spends about three weeks at the bolt- about 4–6 buds at the top of the taproot over an extended period under no-till ing stage before fl owering (Thebaud and (near the soil surface) of over-wintered 124 Plant Protection Quarterly Vol.22(4) 2007 C. bonariensis plants (Wu et al. 2007). This times that of the S wild feature enables the plant to regenerate type during most of from its basal buds after top removal. Dav- the vegetative growth ies (1999) reported that 45 days after top phase and a high removal of C. bonariensis by cutting at the level of resistance at fl owering stage, plants regrew and were an age of 10 weeks, able to produce an amount of dry matter where it is 50–100 of 67 g per plant, further confi rming the times more resistant regenerative ability of this weed. to paraquat (Ye and Gressel 2000). Amsel- Perennation lem et al. (1993) also Conyza bonariensis is often reported as an reported that resist- annual and in some cases as a biennial ance of C. bonariensis (Cunningham et al. 1981, Lazarides et al. to paraquat increased 1997, Peng et al. 1998, Wagner et al. 1999). when plants were in- The ability to regrow from its basal buds duced to flower by Figure 3. Re-sprouting of Conyza bonariensis after the might contribute to its biennial nature. long days. Two mechanisms removal of aboveground part. Physiology of paraquat resist- Conyza bonariensis is a quantitative long- ance in C. bonariensis have been proposed: winter, forms a basal rosette stage over day species. It bolts and fl owers earlier sequestration at plasmalemma, and detoxi- winter and produces seeds in the follow- under long-day (16 h) than under short- fi cation of toxic oxygen species generated ing spring or summer. A small fraction of day (8 h) conditions (Zinzolker et al. 1985). by paraquat (Norman and Fuerst 1997). C. bonariensis also germinates in spring and However, plants grown under 10 h light Norman et al. (1994) reported that the lat- bolts without an over-wintering growth period, 50 µE m−2 s−1 at 25°C remain veg- eral movement of 14C paraquat from the stage. On-farm monitoring of fi eld emer- etative. Although bolting occurs, the stalk point of application on the adaxial surface gence over time in a light sandy loam soil does not fl ower before senescence (Amsel- of intact leaves incubated in darkness was showed that 99% emergence occurred in lem et al. 1993). Conyza bonariensis fl ow- signifi cantly restricted in the R biotype late autumn, early and late winter, and 1% ers considerably earlier than other Conyza relative to the S biotype, indicating that emerged in mid spring (Wu et al. 2007). species (Thebaud and Abbott 1995). Of the paraquat resistance in Conyza is correlated Conyza bonariensis fl owers all year round, fi ve species, C. bonariensis is the earliest to with restricted movement (sequestration) although fl owering is promoted by a long fl ower, followed by C. sumatrensis, C. ca- of the herbicide in the R biotype. On the photoperiod, such as a 14 h light period nadensis, along with C. parve and probably other hand, C. bonariensis contains a com- (Zinzolker et al. 1985, Amsellem et al. C. bilbaoana (Michael 1977). plex of enzymes capable of detoxifying the 1993). The light compensation point, light reactive oxygen species generated by the Little information is available on the saturation point and the maximum net photosystem I blocker paraquat, keeping importance of emergence cohorts (autumn photosynthetic rate of C. bonariensis were the plant alive until the paraquat is dissi- or spring) to the population dynamics of estimated at 21.7 µmol m 2 s−1, 1606 µmol pated (Ye et al. 2000, Ye and Gressel 2000). C. bonariensis. Over-wintering C. bonarien- −2 −1 −2 −1 m s and 22.6 µmol CO2 m s , respec- The levels of plastid superoxide dismutase sis plants of the autumn cohort seem to tively, compared to 13.9 µmol m−2 s−1, 2050 and glutathione reductase are generally have certain ecological advantages. Al- −2 −1 −2 −1 µmol m s and 20.7 µmol CO2 m s for higher in resistant compared with suscep- though very limited emergence occurs in C. canadensis (Guo et al. 2004), indicating tible plants during periods of high-level mid-winter, young autumn or early win- that C. bonariensis is less tolerant to shad- paraquat resistance, but they were simi- ter seedlings actively grow during winter ing than C. canadensis. lar during periods of low-level resistance despite cold and dry conditions. Surpris- Other physiological information has (Amsellem et al. 1993). ingly, while there does not appear to be mainly derived from the investigation of These two mechanisms act in a syn- much growth above ground, root growth mechanisms of herbicide resistance in C. chronized manner. Shaaltiel and Gressel progresses extremely well. The tap roots bonariensis. Photosynthetic electron trans- (1987) reported that paraquat is not im- of C. bonariensis can grow more than 35 cm port in the chloroplasts of triazine-resistant mediately sequestered. It rapidly inhibits deep into the soil to absorb available wa- (R) biotypes of C. bonariensis is unaffected the chloroplast function of both S and R ter, thereby surviving the severe drought by atrazine and simazine, as shown by plants. However, the inhibition is transient conditions frequently experienced in fl uorescence induction measurements in (2 h) in the R biotype and irreversible in the winter in south-eastern Queensland. whole leaves (Prado 1989). In Hill reaction the S biotype. The R biotype has the ca- Regehr and Bazzaz (1976) also found that assays, the R biotype shows high level of pability to mobilize the high constitutive over-wintering plants of C. canadensis at resistance to atrazine and simazine, with a levels of the enzymes in the active oxy- the rosette stage were capable of substan- resistance factor in the range of 350–550. gen detoxifi cation pathway to temporar- tial carbon fi xation and energy storage at Extensive research has been conducted ily protect the plant from paraquat dam- low temperatures. The establishment of to understand the resistance of C. bonarien- age while the paraquat is being actively a strong root system over winter months sis to paraquat. As measured by chloro- sequestered. In fact, it has been suggested provides suffi cient food reserves for rapid phyll fl uorescence suppression, paraquat- that only small increases in enzyme levels growth during the following spring. It is resistant (R) C. bonariensis is about 100-fold would be needed for 20-fold resistance, diffi cult to control these over-wintered C. resistant to paraquat compared to the sus- based on the moderate enzyme increases bonariensis plants, although they are small ceptible (S) biotype (Vaughn et al. 1989). correlated with 300-fold resistance (Am- in appearance (Figure 4). In fact these Shaaltiel et al. (1988) reported that one sellem et al. 1993). plants are well developed, thereby requir- dominant gene pleiotropically controlled ing higher management inputs to control the paraquat resistance in C. bonariensis. Phenology them (Wu and Walker 2004). Conyza bonariensis has two periods of resist- Conyza bonariensis often follows a winter ance during vegetative (rosette) growth: a or summer annual life cycle. It predomi- Mycorrhiza low level of resistance with an I50 value 10 nantly emerges in autumn and early Little information is available. One report Plant Protection Quarterly Vol.22(4) 2007 125 shows that there is no vesicular-arbuscular the frequent high intensity summer storms (Michael 1977, Zinzolker et al. 1985, Wu et mycorrhizal association with C. bonariensis experienced in the northern grain region, al. 2007). A 10 minute exposure to light in- plants collected from Heron Island, Aus- through a combination of strong wind duced full germination after the seeds were tralia (Peterson et al. 1985). and surface run-off, and through the wa- soaked in darkness for 1–2 days. However, ter movement in irrigation channels and after 4–6 days of dark incubation, soaked Reproduction waterways. Prolifi c seed production, in seeds became unresponsive to the short Floral biology combination with dispersal by wind and period of light treatment. Exposure to Conyza bonariensis is self-compatible, water, suggests that the spread of C. bon- continuous white light stimulated germi- and apparently not actively pollinated ariensis across an agricultural landscape nation of the unresponsive soaked seeds. by insects, suggesting either autogamy could be very rapid. Pre-chilling also exerted a positive effect or wind-pollination (Thebaud et al. 1996, on germination (Davies 1999). However, Zelaya et al. 2007). Conyza bonariensis pro- Physiology of seeds and germination it was found that pre-chilling of soaked duced large and rounded capitula, with Conyza bonariensis is photoblastic and ger- seeds at 5°C did not replace the light re- capitulum total length of 5.1 mm and base mination is greatly stimulated under light quirement for germination (Zinzolker et width of 3.6 mm, while C. canadensis produced small and elongated capitula, with capitulum total length of 4.0 mm and base width of 2.2 mm. The number of fl orets per capitulum was estimated at 211, which is about three times greater than C. canadensis, and two times greater than C. sumatrensis (Thebaud and Abbott 1995).

Seed production and dispersal Reproductive capacity of C. bonariensis is high relative to total plant biomass (Figure 5). Conyza bonariensis plants are capable of producing up to 357 561 wind-dispersed seeds per plant (Kempen and Graf 1981). Average seed production was estimated at 290 per head and 266 753 per plant from Kern County, California (Kempen and Graf 1981), and at 400 per head and 119 100 per plant from south-eastern Queensland (Wu et al. 2007). Among the mature seeds produced, 80% are viable. The prolifi c seed production of C. bonariensis suggests a capacity of the weed to build up seed banks in a short time. Seed settling velocity is a useful indi- rect measure of dispersal ability, with low settling velocity corresponding to high Figure 4. Over-wintered small seedlings of Conyza bonariensis. dispersal ability (Andersen 1992). The seeds of C. bonariensis plants are enclosed singly in small hard achenes. The achenes are equipped with a tuft of bristles known as the pappus (Figure 6). The pappus en- hances the seed dispersal distance by reducing the rate of gravitational settling. Conyza bonariensis seeds have an average settling velocity of 0.291 m sec−1 (SD = 0.0728) (Andersen 1992), which is lower than 0.323 m sec−1 (SD = 0.0687) reported for a similar Conyza species, C. canadensis (Dauer et al. 2006). There were signifi cant variations in seed settling velocity among plants within C. bonariensis and among infl orescences and seeds within plants. The variability in seed settling velocities within C. bonariensis could be due to differences in the ratio of pappus area to seed mass, or to variations in pappus geometry (An- dersen 1992). These differences may arise through differences in the amount of pappus produced by an individual achene, in the mass of the enclosed seed or both (Augspurger 1986). The small, light seed of C. bonariensis is prone to long distance dissemination by Figure 5. Fecundity of Conyza bonariensis. 126 Plant Protection Quarterly Vol.22(4) 2007

Figure 6. Conyza bonariensis seeds. al. 1985). The cardinal (base, optimum and C. sumatrensis because they frequently oc- compared to crosses with the diploid (2n = maximum) temperatures for germination cur in sympatry, along with the presence 18) C. canadensis (Zelaya et al. 2007). of C. bonariensis are estimated at 4.2, 20 and of morphologically intermediate forms 35°C (Wu et al. 2007). in Europe (Thebaud and Abbott 1995). Population dynamics Conyza bonariensis seed is readily ger- However, detailed morphological stud- Conyza bonariensis is often reported as a minable when it matures and germinates ies and isozyme analyses have confi rmed weed of no-till farming systems (Somer- as long as conditions favour germination. that hybridization does not occur between vaille and McLennan 2003). Compared to Due to the fact that the weed fl owers all these species. The isozyme banding pat- spring emergence, over-wintering C. bon- year round, it has potential to complete terns within each taxon are neither a com- ariensis plants that emerge in autumn have multiple life cycles in a year. The potential bination of those observed in any pair of greater implications for the population dy- for population growth will be very high if the other taxa nor a subset of that of any namics of this weed (Wu et al. 2007). the weed is not controlled. other taxon. Thebaud and Abbott (1995) Prieur-Richard et al. (2000) studied the Conyza bonariensis emergence is very concluded that these three Conyza species invasiveness of C. bonariensis in pre-estab- sensitive to soil burial. Seedlings emerge have diverged genetically prior to their lished plant communities consisting of only from the soil surface or from a depth introduction to Europe and maintained three functional groups (legumes, grasses of 0.5 cm. No emergence occurred below their genetic integrity despite the poten- and Asteraceae) and a range of plant spe- 2 cm of burial depth (Wu et al. 2007). tial for hybridization due to their broad cies within each group. Increasing species Soil burial depths have signifi cant ef- sympatry. They suggest that hybridization richness of the resident communities im- fects on seed persistence. The persistence or gene introgression is rare among these pacted the demographic dynamics of C. pattern shows an initial rapid drop fol- species because of pre- or postzygotic iso- bonariensis through both a loss in biomass lowed by a slow but steady decline over lation, including the possibility of strong and a decreased allocation to reproduc- time. Wu et al. (2007) reported that after selection against hybrids in the introduced tion. The establishment, vegetative growth three years of burial, there were about range. Zelaya et al. (2007) also claimed (fi nal biomass) and net fecundity of C. bon- 7.5%, 9.7% and 1.3% viable seeds at 10, that the scarcity of natural hybridization ariensis reduced signifi cantly with the in- 5, and 0–2 cm soil depths, respectively. in Conyza is probably due to the enclosed creased number of species per functional Although 1.3% viability after three year involucre arrangement in Conyza and the group. Species richness had no effects on burial at 0–2 cm soil depth is a relatively autogamous nature of the genus. C. bonariensis survival. small fraction, its signifi cance should not However, hybrids with unknown fecun- Functional richness (the number of func- be underestimated due to the massive dity, namely Conyza × fl ahaultiana (Thell.) tional groups) had no effect on the vegeta- seed production of the weed. Weed man- Sennen and Conyza × daveauiana Sennen tive, reproductive and establishment pa- agement plans would need to be in place have been reported to have derived from rameters of C. bonariensis. However, the for more than three years in order to con- crosses between C. bonariensis and C. su- functional identity (species composition) trol populations of this weed. matrensis in Spain and France (McClintock played an important role in regulating the Seed persistence is also affected by soil and Marshall 1988, Zelaya et al. 2007). Hy- growth and net fecundity of C. bonariensis type. Conyza bonariensis seeds buried in a brids, Conyza × mixta Fouc. & Neyr are re- (Prieur-Richard et al. 2000). The introduc- light sodosol soil had signifi cantly higher portedly derived from crosses between C. tion of any legume species into the spe- percentage viability than those buried in bonariensis and C. canadensis in Belgium, cies mix increased the biomass and conse- the heavy textured vertosol soil. When France, Britain and Portugal (Zelaya et al. quently the net fecundity of C. bonariensis, exhumed after 24 months of burial, 8% vi- 2007). Sida (2003) also reported a putative resulting in an increased number of seeds able seeds were detected in the light soil, hybrid between C. bonariensis and C. triloba per seedhead. However, the presence of and 2% in the heavy soil (Wu et al. 2007). Decne. in the Czech Republic. grass species tended to decrease vegeta- The European Conyza hybrids are tive growth and reproductive effort. Com- Vegetative reproduction commonly poor in vigour. It has been munities with fewer Asteraceae and grass- Conyza bonariensis reproduces only by speculated that ploidy differences may es were associated with increases in the seeds. be a key barrier limiting hybridization reproductive effort of C. bonariensis, while between Conyza species. More compatible its establishment was inhibited by the Hybrids and vigorous hybrids would be expected presence of grasses. Soil nitrates affected Hybridization has been suspected be- from crosses between the allopolyploids C. bonariensis net fecundity both indirectly tween C. bonariensis, C. canadensis and (2n = 54) C. bonariensis and C. sumatrensis, via its biomass and directly through its Plant Protection Quarterly Vol.22(4) 2007 127 allocation to reproduction (Prieur-Richard 1955). Tomato spotted wilt virus causes g ha−1 caused 60 to 82% biomass reduction et al. 2002a). Soil nitrate concentration was spotted wilt of groundnut in Queensland of C. bonariensis populations collected from negatively correlated with grass biomass (Helms et al. 1961). More recently, the pres- 21 cropping paddocks, compared to the and positively correlated with legume bio- ence of lettuce mosaic virus (LMV) on C. untreated controls, while the biomass re- mass (Prieur-Richard et al. 2000). bonariensis plants in Brazil has been con- duction was 73 to 99% on populations from Conyza bonariensis seedling establish- fi rmed by a range of techniques, including non-cropping areas with little or no sus- ment and survival increased with an electron microscopy, biological, serologi- pected previous exposure to glyphosate. increase in Asteraceae species richness cal and molecular analysis (Chaves et al. (Prieur-Richard et al. 2000). The increased 2003). The occurrence of pests, diseases Benefi cial seedling establishment of C. bonariensis in and viruses in C. bonariensis is signifi cant Conyza bonariensis has been used in popu- the absence of Poaceae or Fabaceae was since this weed may act as a reservoir for lar medicine as an anti-infl ammatory, diu- not due to light competition but to light potential infestation in agricultural crops. retic, vermifuge, and for the treatment of quality. Abundant grass and legume foli- Research on allelopathy has shown that haemorrhoids and diarrhoea (Maia et al. age can modify far red light radiation. The shoot residues of C. bonariensis increase 2002). It is commonly used to treat der- increased survival of C. bonariensis in com- parasite infestation of branched broom- matological disorders (Pereira et al. 2005). munities dominated by Asteraceae spe- rape (Orobanche ramosa L.) on tomato Ground seed is highly aromatic and can be cies was a result of reduced herbivory on plants (Qasem 2002). used as an insect repellent (Cunningham C. bonariensis seedlings when compared Conyza bonariensis is listed as an agricul- et al. 1981). Internally, a 1% infusion of the to communities dominated by grasses tural and environmental weed by Randall whole plant is used as a liver protector (Prieur-Richard et al. 2002b). (2002). It is rated 4 on a scale of 0–5 as a and against stomach ulcers (Lombardo weed affecting natural ecosystems and a 1970, Alonso et al. 1992). Infusions at 3–4% Importance highest rating of 5 in agricultural ecosys- are used as a diuretic in problems of the Detrimental tems (Groves et al. 2003). Conyza bonariensis genital-urinary system. Decoctions of the Conyza bonariensis is innocuous to stock is a weed of pastures and many fi eld crops, whole plant (10%) are used for the elimi- (Andrade and Holzhacker 1959). However, such as maize, soybean, sorghum, cotton, nation of uric acid, a depurative and as an it imparts taint to the milk and depreciates chickpea, wheat, and lucerne (Milne 1991, antirheumatic (Arrillage 1969, Lombardo milk quality (Molfi no 1947, Whittet 1968). Chaudhry et al. 2001, Wu and Walker 2004, 1970). Conyza bonariensis is also used ex- It is rarely eaten by stock unless other for- Heap 2007). It competes signifi cantly for ternally as antiseptic in wounds (Alonso age is not available (Molfi no 1947). The water and nutrients, especially stored soil 1992, Lombardo 1970). Cataplasms made sap of C. bonariensis plants can cause skin moisture in wheat and dryland sorghum with fresh leaves are very popular for their irritation (Cunningham et al. 1981). Conyza crops. Walker and Wu (2006) reported healing properties (Davies 1999). It is pos- bonariensis has also been reported to cause that C. bonariensis causes signifi cant yield sible to cultivate C. bonariensis for a poten- contact dermatitis in South Australia (Bur- reduction in sorghum. Compared to the tial biomass production of 17 444 kg dry ry and Kloot 1982). weed-free treatment achieved by early weight ha−1 (Davies 1999). Conyza bonariensis is a wild host to a pre-plant application of atrazine at 2000 Conyza bonariensis is rich in essential range of pests and diseases. It is a host to g a.i. ha−1, C. bonariensis caused sorghum oils, with 0.1–0.5% oil content found for Nysius graminicola Kolenati and N. cymoides yield loss of 30–31% even in the low-rate the whole plant (Maia et al. 2002, Barbosa Spinola, which cause serious damage to a atrazine treated plots at 1000 g a.i. ha−1. et al. 2005). Concerted efforts have been range of summer vegetable and fruit crops, Conyza bonariensis has doubled fallow made to identify the volatile constituents particularly sorghum, grape, tomato and weed control costs (Thorn 2004). The cost of the essential oils from C. bonariensis peach (Blando and Mineo 2005). It is an is likely to increase substantially due to the (Kong et al. 2001, Maia et al. 2002, Barbosa alternate host for Basidiophora entospora weed’s rapid development of resistance to et al. 2005, Tzakou et al. 2005). The oils of Roze & Cornu, causing downy mildew on herbicides. Biotypes of C. bonariensis have C. bonariensis were rich in limonene, (E)- ornamental crops (asters) (Francis 1998). evolved resistance to a range of herbicides β-ocimene, (E)-β-farnesene, β-caryophyl- Reniform nematode (Rotylenchulus reni- with different modes of action in seven lene, cis-lachnophyllum ester, matricaria formis Linford & Oliveira) is also found on countries (Heap 2007). Populations resist- ester, and germacrene D (Maia et al. 2002, the roots of C. bonariensis in Brazil (Ferraz ant to paraquat have been identifi ed in or- Tzakou et al. 2005, Barbosa et al. 2005). 1985). chards, vineyards and roadsides in Egypt, Tzakou et al. (2005) detected a total of 56 Conyza bonariensis is identifi ed as a host Japan and South Africa (Fuerst et al. 1985, compounds and identifi ed 26 from the of the formicid Dorylus orientalis West- Heap 2007). Triazine resistant populations essential oils. The essential oil profi les of wood, a pest infesting a variety of horti- have been reported in Israel and Spain C. bonariensis differ between collections cultural crops in Hunan, China (Xie and (Prado et al. 1989, Heap 2007). Biotypes of (Maia et al. 2002), growth stages (Tzakou Yao 1989). Dorylus orientalis eggs are laid C. bonariensis have also been confi rmed to et al. 2005), and plant parts (Barbosa et al. 3–5 cm underground on the roots of C. have evolved resistance to chlorsulfuron, 2005). bonariensis plants. Wingless adults feed an acetolactate synthase (ALS) inhibitor, in The essential oils from C. bonariensis on the epidermis of the host’s root sys- industrial sites and forests in Israel. Since have been screened for anti-infl ammatory tem and on the stem up to 3 cm from the the fi rst report of a C. bonariensis popula- activity in the mouse model of pleurisy ground. In addition, C. bonariensis serves tion resistant to glyphosate in South Africa induced by zymosan and lipopolysac- as a wild host to Uroleucon bereticum (E.E. in 2003, glyphosate-resistant populations charide (LPS) (Souza et al. 2003). Oral Blanchard) (Hemiptera: Aphididae) in of C. bonariensis have been identifi ed in administration of the main monoterpene Argentina (Delfi no and Stary 2004). Brazil, Colombia and Spain (Urbano et al. constituent of the essential oil, limonene, Conyza bonariensis has been reported as 2005, Moreira et al. 2007, Heap 2007). was able to inhibit LPS-induced infl am- an alternative host of a number of viruses, Differential responses to glyphosate mation, including cell migration, which such as witches’ broom virus and tomato have also been found among C. bonariensis helped to control the infl ammatory process spotted wilt virus. Witches’ broom virus populations in Australia. Populations col- during some bacterial infections. Kuiate et causes severe infection of tomatoes. New lected from cropping paddocks are more al. (2005) reported that the essential oils of leaves develop chlorotic margins, axil- tolerant than those collected from non-ag- E. fl oribundus (a synonym to C. bonariensis) lary buds and fl ower calyces show hyper- ricultural situations (Walker and Robinson showed broad antifungal activities against trophy; eventually the plants die (Costa 2007). Application of glyphosate at 675 a.e. Trichophyton rubrum (Castelani) Semon, 128 Plant Protection Quarterly Vol.22(4) 2007 Trichophyton mentagrophytes (Robin) Blan- tolerate high levels of glyphosate appli- Spray.Seed®, achieved the most effective chard, Candida albicans (Robin) Berkhout cation, due to leaf structures that protect and consistent control of C. bonariensis at and Cryptococcus neoformans (Sanfelice) against herbicide penetration, such as high various growth stages in fallows (Wu et Vuillemin. The fl ower oil was more active trichome density, high cuticle thickness al. 2006). than the leaf oil. and low stomatal density in the adaxial The use of residual herbicides through The fungicidal activity of C. bonarien- side of the leaf (Procopio et al. 2003). The root uptake is another control strategy sis against Macrophomina phaseolina (Tassi) natural leaf barriers to herbicide penetra- which overcomes the diffi culty of foliar Goid has been assessed (Gautam et al. tion determine the limited success of any uptake arising from the protective leaf bar- 2003). A methanol extract of C. bonarien- single herbicide application. A successful riers of C. bonariensis (Wu et al. 2006, Wu sis at 1000 µg mL−1 caused 17% inhibition herbicide control program depends high- et al. 2007). Residual herbicides are often against M. phaseolina, a soilborne fungus ly on the timing of application, the use of used in mixture with glyphosate to per- causing charcoal rot. In addition, Charu herbicide mixtures, sequential application form dual actions through both foliar and and Kaushik (2003) claimed that a dry as well as the strategic use of residual her- root uptake. Higher rates of atrazine (2000 methanolic extract of C. bonariensis sig- bicides (Kempen 1988, Wu et al. 2007) g a.i. ha−1) or Primextra (atrazine + metol- nifi cantly inhibited three soyabean fun- Timeliness of herbicide application has achlor at 1184 and 928 g a.i. ha−1) provide gal pathogens: Colletotrichum truncatum a signifi cant effect upon control effi cacy. good control of subsequent fl ushes in win- (Schw.) Angdrus and Moore, Fusarium It is critical to apply herbicides when the ter fallows. The effi cacy of pre-emergence oxysporum (Schlet) emend Snyd. & Hans, plant is small and actively growing. Her- herbicide often depends on the timing and and M. phaseolina, which cause pod blight, bicide effi cacy decreases as the plant ma- amount of rainfall. wilt/root rot, and charcoal rot diseases of tures. Young seedlings at the rosette stage For in-crop weed control, it is imperative soyabean, respectively. Methanol extracts (<10 cm across) are easy to control. How- to control emerged weeds prior to sowing. from the leaves of C. bonariensis are in- ever, applying herbicide to very young Application of glyphosate ± 2,4-D amine hibitory to mushroom fungal pathogens, seedlings (from the cotyledon to two-leaf followed by Spray.Seed® or paraquat ef- Mycogone perniciosa Magn. and Verticillium stage) is not successful due to limited leaf fectively controls C. bonariensis at various fungicola (Preuss) Hassebrauk (Charu et al. area for herbicide uptake (Taylor 2007). growth stages (Wu and Walker 2004). 2003). The essential oil from C. bonariensis Control programs should target winter Conyza bonariensis control in wheat re- at 1000 ppm inhibited mycelial growth of fallow, rather than summer fallow, due to quires residual herbicides to manage a Aspergillus fl avus Link ex Gray and at 3000 the predominant emergence in autumn. In number of fl ushes in-crop. Pre-plant ap- ppm was fungitoxic (Singh et al. 1984). As- addition, control effi cacy in the summer plication of Glean (chlorsulfuron at 15 g pergillus fl avus is a fungus that produces declines rapidly due to the fact that weeds a.i. ha−1) provides effective seasonal con- afl atoxins (Mahmoud 1999). are often under severe moisture stress, as trol of C. bonariensis in wheat, which can Alcoholic extracts of C. bonariensis well as unfavourable spraying conditions be followed up by Tordon 242 (MCPA + showed a broad spectrum of antimicro- (high temperature and low relative hu- picloram), or 2,4-D amine to target sur- bial activity (Gautier et al. 1959, Olano et al. midity) at the time of application. vivors. Post-emergent application of Ally 1996). Chaudhry et al. (2001) reported that Effective control of C. bonariensis in fal- (metsulfuron methyl at 4.2 g a.i. ha−1) petroleum ether extracts of the aerial parts low cannot be achieved with any single achieved variable results between years. of C. bonariensis were toxic to brine shrimp, herbicide alone (Wu et al. 2006). Contact Consistent results were obtained with Ally and the methanol extract of C. bonariensis herbicides alone, such as Spray.Seed® either mixed with Tordon 242 (MCPA + displayed signifi cant antifungal activity (paraquat + diquat at 324 and 276 g a.i. picloram), or followed by 2,4-D amine against Cladosporium cucumerinum Ellis & ha−1), or paraquat at 325 g a.i. ha−1, are inef- (Wu et al. 2006). Arth. A methanol extract of C. bonariensis fective, even when they are applied early. In sorghum, control efforts should was found to be inhibitory against xan- Re-growth after 2–3 weeks is common af- be focused on the existing C. bonariensis thine oxidase (Kong et al. 2001), an enzyme ter these treatments (Wu et al. 2006). populations before sowing. In-crop emer- closely related to hyperuricemia and gout Use of appropriate herbicide mixtures gence is expected to be very limited due (Tsutomu et al. 1991, Cos et al. 1998). Fur- is a key to success. The addition of a suit- to temperatures unfavourable for germi- ther study also found that the crude ex- able mixing partner to glyphosate, such nation during summer (Wu et al. 2007). A tracts of C. bonariensis contain inhibitors as Ally (metsulfuron methyl), Amitrole pre-plant application of atrazine at 2000 against butyrylcholinesterase (Khan et al. T (amitrole + ammonium thiocyanate), g a.i. ha−1 is very effective in providing 2006). 2,4-D ester, 2,4-D amine, Tordon 75D (2,4- residual control in sorghum. A sequential Conyza bonariensis is a potential oilseed D amine and picloram), Grazon DS (tri- application of glyphosate at 900 g a.e. ha−1 source of epoxy, crepenynic, erucic and clopyr and picloram), dicamba and Garlon other fatty acids, as well as of seed gum, 600 (triclopyr), improves control effi cacy steroids and pulp (White et al. 1971). to over 90%. Three non-glyphosate mixes, 2,4-D ester + Amitrole T, 2,4-D amine + Legislation Amitrole T, and 2,4-D amine + Ally, also Conyza bonariensis is not currently classi- achieved over 90% control. These mixes fi ed as a noxious weed in Australia. No provide alternative solutions to rotate regulatory legislation is applied. with glyphosate, thereby minimising the risk of evolving glyphosate resistance (Wu Weed management et al. 2006). Herbicides The re-sprouting characteristics of C. Currently only Spray.Seed® and Tordon bonariensis, and prolonged emergence pat- 75-D are registered for C. bonariensis con- terns between autumn and spring suggest trol in Australia. However, in the past dec- that sequential application techniques are ade, a range of pre- and post-emergence important tactics for effective C. bonariensis herbicides have been evaluated in both control. Conyza bonariensis plants of differ- fallow and in-crop situations. ent growth stages often co-exist in the fi eld Figure 7. Co-existence of Conyza Conyza bonariensis plants, especially at (Figure 7). A double-knock technique, i.e. bonariensis plants at different a mature growth stage, seem to naturally glyphosate followed several days later by growth stages. Plant Protection Quarterly Vol.22(4) 2007 129 mixed with 2,4-D amine at 900 g a.e. ha−1 Natural enemies Garg, G.K. (2003). Fungicidal poten- or dicamba at 500 g a.e. ha−1 , followed by There is no information available on the tial of Kumaon and Tarai region plants at-planting atrazine at 1000 or 2000 g a.i. natural enemies of this weed. against mushroom fungal pathogens. ha−1 also provides effective control. Allelopathy Journal 11, 63-70. In lucerne, Milne (1991) reported that Acknowledgments Chaudhry, B.A., Janbaz, K.H., Uzair, M. hexazinone at 750 or 1000 g a.i. ha−1 + Cal- Mr Andrew Storrie of NSW Department of and Ejaz, A.S. (2001). Biological studies tex Summer Oil (1%) achieved 94–99% Primary Industries and Dr Rex Stanton of of Conyza and Euphorbia species. Journal control of C. bonariensis. Metribuzin at E.H. Graham Centre are kindly acknowl- of Research (Science) 12, 85-8. 0.48 kg ha−1 gave excellent control of C. edged for their constructive and critical Chaves, A.L.R., Braun, M.R., Eiras, M., bonariensis in an established ley system of comments on this manuscript. Colariccio, A. and Galleti, S.R. (2003). lucerne/white clover/Dactylis glomerata Erigeron bonariensis, an alternative host L./Bromus inermis Leyss, producing the References of lettuce mosaic virus in Brazil. Fitopa- highest fodder dry matter yield (Perez and Alonso, E., Bassagoda, M.J. and Fereira, F. tologia Brasileira 28, 307-11. Duarte 1991). (1992). Yuyos; Uso Racional de las Plan- Cos, P., Ying, L., Calomme, M., Hu, J.P., Fallow treatment with Flame (imaza- tas Medicinales. Editorial Fin de Diglo, Cimanga, K., Van Poel, B., Pieters, L., pic) and in-crop treatment with Balance Montevideo, pp. 156. Vlietinck, A.J. and Berghe, V.D. (1998). (isoxafl utole) + simazine are thought to be Amsellem, Z., Jansen, M., Driesenaar, A. Structure activity relationship and clas- reasonable options for C. bonariensis con- and Gressel, J. (1993). Developmental sifi cation of fl avonoide as inhibitors of trol in chickpea. In cotton, combinations variability of photooxidative stress tol- xanthine oxidase and superoxide scav- of diuron, fl uometuron and prometryn erance in paraquat-resistant Conyza. engers. Journal of Natural Products 61, followed by inter-row cultivation or chip- Plant Physiology 103, 1097-106. 71-6. ping have been suggested (Wu and Walker Andersen, M. (1992). An analysis of vari- Costa, A.S. (1955). Witches’ broom of 2004). ability in seed settling velocities of sev- Erigeron bonariensis. Bragantia 14, iii-v. eral wind-dispersed Asteraceae. Ameri- Cronquist, A. (1943). The separation of Other treatments can Journal of Botany 79, 1087-91. Erigeron from Conyza. Bulletin of the Tor- Conyza bonariensis is a poor competitor. Its Andrade, S.O. and Holzhacker, E.L. (1959). rey Botanical Club 70, 629-32. growth (biomass) signifi cantly decreased Investigations on toxic plants in Sao Cunningham, G.H., Mulham, W.E., with increasing species richness in a di- Paulo State. Arquivos do Instituto biológ- Milthorpe, P.L. and Leigh, J.H. (1981). verse plant community (Prieur-Richard et ico de São Paulo 26, 55-88. ‘Plants of western New South Wales’. p. al. 2000). Ward and Hamilton (2004) found Arrillage, B. (1969). Plantas Medicinales. 662. (N.S.W. Government Printing Of- that C. bonariensis grew well in wide-row Editorial Nuestra Tierra, Montevideo. fi ce, Soil Conservation Service of NSW, crops such as chickpea and sorghum and Nuestra Tierra No 31, pp. 60. Sydney). in areas of poor crop establishment irre- Augspurger, C.K. (1986). Morphology and Danin, A. (1976). On three adventive spe- spective of the time of year and crop type. dispersal potential of wind-dispersed cies of Conyza (Compositae) in Greece. Growing more competitive winter cereals diaspores of neotropical trees. American Candollea 31, 107-9. and avoiding wide row spacing should Journal of Botany 70, 1031-7. Dauer, J.T., Mortensen D.A. and Hum- achieve better control (Wu and Walker Auld, B.A. and Medd, R.W. (1987). ‘Weeds ston, R. (2006). Controlled experiments 2004). – an illustrated botanical guide to the to predict horseweed (Conyza canaden- There is also potential for the stra- weeds of Australia’, p. 96. (Inkata Press, sis) dispersal distance. Weed Science 54, tegic use of tillage to control this weed. Melbourne). 484-9. Wu et al. (2007) reported that C. bonarien- AVH. (2007). Australia’s Virtual Herbar- Davies, P. (1999). Propagation of “Yerba sis is very sensitive to seed burial, with ium. Distribution map of Conyza bon- carnicera” (Conyza bonariensis (L.) no emergence occurred below 2 cm soil ariensis. http://www.rbg.vic.gov.au/ Cronq. var. bonariensis, Compositae). depth. Conyza bonariensis is highly re- cgi-bin/avhpublic/avh.cgi. Accessed Acta Horticulturae 502, 121-4. sponsive to cultivation. Werth and Walker on the 26 June, 2007. Delfi no, M.A. and Stary, P. (2004). Uroleu- (2007) showed that chisel and disc plough Barbosa, L.C.A., Paula, V,F., Azevedo, A.S., con bereticum (E.E. Blanchard) (Hemi- were effective in suppressing C. bonarien- Silva, E.A.M. and Nascimento, E.A. ptera, Aphididae) and its new endemic sis emergence. Limited emergence with (2005). Essential oil composition from parasitoid species (Hymenoptera, Braco- cultivation is probably due to the burial some plant parts of Conyza bonariensis nidae, Aphidiinae) in Argentina. Neotrop- effect and changing soil surface dynam- (L.) Cronquist. Flavour and Fragrance ical Entomology. Sociedade Entomologica ics. Similarly, Brown and Whitwell (1988) Journal 20, 39-41. do Brasil (SEB) 33, 577-81. found that even minimum tillage (discing) Blando, S. and Mineo, G. (2005). Tritrophic Everett, J. (1992). Conyza. In ‘Flora of New in spring or autumn effectively control- interrelations of two economically in- South Wales’, ed. G.J. Harden, Volume led C. canadensis. Inter-row cultivation and teresting ligaeid pests (Heteroptera). Bol- 3, pp 197-200. (New South Wales Uni- chipping are available options to control lettino di Zoologia Agraria e di Bachicol- versity Press, Sydney). mature and stressed weeds in wide-row tura 37, 211-23. Ferraz, L.C.C.B. (1985). Susceptibility of crops such as cotton and sorghum (Wu Brown, S.M. and Whitwell, T. (1988). In- various common weeds in Sao Paulo and Walker 2004). fl uence of tillage on horseweed, Conyza State to Rotylenchulus reniformis. Nema- Mowing is not an effective control op- canadensis. Weed Technology 2, 269-70. tologia Brasileira 9, 143-52. tion. It encourages lateral branching from Burry, J.N. and Kloot, P.M. (1982). The Finot, S.V.L., Urbina, P.A., Minoletti, the base of the plants, hardening them off. spread of Composite (Compositae) O.M.L., Wilckens, E.R., Figueroa, R.M. Mowing has also resulted in reducing the weeds in Australia. Contact Dermatitis and Riquelme, C.M. (1996). Achene leaf area for herbicide coverage (Milne 8, 410-3. and seedling morphology of Asteraceae 1991), making control with post-emergent Charu, A. and Kaushik, R.D. (2003). Fun- weed species from south-central Chile. herbicides ineffective. Conyza bonariensis is gicidal activity of plants extracts from I. Agro-Ciencia 12, 15-29. not controlled by solarization under plas- Uttaranchal hills against soybean fun- Fuerst, E.P., Nakatani, H.Y., Dodge, A.D., tic sheets (Silveira et al. 1988). gal pathogens. Allelopathy Journal 11, Penner, D. and Arntzen, C.J. (1985). 217-28. Paraquat resistance in Conyza. Plant Charu, A., Kaushik, R.D., Kumar, A. and Physiology 77, 984-9. 130 Plant Protection Quarterly Vol.22(4) 2007 Francis, S.M. (1998). Basidiophora entospora. from Conyza bonariensis. Phytochemistry Soubes, M., Vazquez, A., Vero, S. and IMI Descriptions of Fungi and Bacteria. 58, 645-51. Bassagoda, M.J. (1996). Screening of CAB International, Wallingford, UK, Kuiate, J.R., Tsona, A.A., Foko, J., Bessiere, Uruguayan medicinal plants for anti- 69, Sheet 681. J.M., Menut, C. and Amvam-Zollo, P.H. microbial activity. Part II. Journal of Eth- Gautam, K., Rao, P.B. and Chauhan, S.V.S. (2005). Chemical composition and in nopharmacology 53, 111-5. (2003). Antifungal potency of some spe- vitro antifungal properties of essential Peng, C.I., Chung, K.F. and Li, H.L. (1998). cies of family Asteraceae (Compositae) oils from leaves and fl owers of Erigeron Compositae. In ‘Flora of Taiwan’, eds. against Macrophomina phaseolina (Tassi) fl oribundus (H.B. et K.) Sch.Bip. from D.E. Boufford, C.F. Hsieh, P.P. Lowry, Goid. Journal of Mycology and Plant Pa- Cameroon. Journal of Essential Oil Re- H. Ohashi and C.I. Peng, 2nd edition, thology 33, 294-95. search 17, 261-4. Vol. 4, pp. 807–1101. (National Taiwan Gautier, E. and Gerber, F. (1959). Investi- Lazarides, M., Cowley, K. and Hohnen, P. University, Taipei). gación de la actividad antibacteriana de (1997). ‘CSIRO handbook of Australian Pereira, C.O., Lima, E.O., Oliveira, R.A.G., plantas de Córdoba. Boletín de la Socie- weeds’, pp. 47-48. (CSIRO Publishing, Toledo, M.S., Azevedo, A.K.A., Guerra, dad Argentina de Botánica 8, 1-8. Melbourne). M.F. and Pereira, R.C. (2005). Ethnobo- GRIN (Germplasm Resources Informa- Lombardo, A. (1970). ‘Planta Medicinales tanic study of medicinal plants used in tion Network) (2007). http,//www.ars- de la Flora Indígena’, pp. 99-109. (Al- dermatological disorders in Joao Pes- grin.gov/cgi-bin/npgs/html/taxon. manaque del Banco de Seguros del Es- soa-Paraiba, Brazil. Revista Brasileira de pl?104170#dist. GRIN Taxonomy for tado, Montevideo). Plantas Medicinais 7, 9-17. Plants, USDA-ARS. Accessed on 25 Mahmoud, A.L.E. (1999). Inhibition of Perez, M. and Duarte, G. (1991). Weed June 2007. growth and afl atoxin biosynthesis of control in leys. Revista de los CREA 146, Groves, R.H. (Convenor), Hosking, J.R., Aspergillus fl avus by extracts of some 58-64. Batianoff, G.N., Cooke, D.A., Cowie, Egyptian plants. Letters in Applied Peterson, R.L., Ashford, A.E. and Allaway, I.D., Johnson, R.W., Keighery, G.J., Lep- Microbiology 29, 334-6. W.G. (1985). Vesicular-arbuscular myc- schi, B.J., Mitchell, A.A., Moerkerk, M., Maia, J.G.S., da Silva, M.H.L., Zoghbi, orrhizal associations of vascular plants Randall, R.P., Rozefelds, A.C., Walsh M.G.B. and Andrade, E.H.A. (2002). on Heron Island, a Great Barrier Reef N.G. and Waterhouse, B.M. (2003). Composition of the essential oil of Co- Coral Cay. Australian Journal of Botany Weed categories for natural and agri- nyza bonariensis (L.) Cronquist. Journal 33, 669-76. cultural ecosystem management. (Bu- of Essential Oil Research 14, 325-6. Prado, R. de, Dominguez, C. and Tena, M. reau of Rural Sciences, Canberra). McClintock, D. and Marshall, J.B. (1988). (1989). Characterization of triazine-re- Guo, S.L., Fang, F., Huang, H. and Qiang, On Conyza sumatrensis (Retz) E.Walker sistant biotypes of common lambsquar- S. (2004). Studies on the reproduction and certain hybrids in the genus. Watso- ters (Chenopodium album), hairy fl eabane and photosynthetic ecophysiology of nia 17, 172-3. (Conyza bonariensis), and yellow foxtail the exotic invasive plant, Plantago virgi- Michael, P.W. (1977). Some weedy species (Setaria glauca) found in Spain. Weed Sci- nica. Acta Phytoecologica Sinica 28, 787- of Amaranthus (amaranths) and Conyza/ ence 37, 1-4. 93. Erigeron (fl eabanes) naturalised in the Prieur-Richard, A.H., Lavorel, S., Grigulis, Heap, I. (2007). The International Survey Asian-Pacifi c region. Proceedings of the K. and Dos Santos, A. (2000). Plant com- of Herbicide Resistant Weeds. Online. 6th Asian-Pacifi c Weed Science Society munity diversity and invasibility by July 05, 2007. Available www.weed- Conference, (Jakarta, Indonesia, 11-17 exotics, invasion of Mediterranean old science.com. July 1977). Asian-Pacifi c Weed Science fi elds by Conyza bonariensis and Conyza Helms, K., Grylls, N.E. and Purss, G.S. Society, Jakarta, Indonesia, 1, 87-95. canadensis. Ecology Letters 3, 412-22. (1961). Peanut plants in Queensland Milne, B.R. (1991). Flax-leaf fl eabane (Co- Prieur-Richard, A.H., Lavorel, S., Dos San- infected with tomato spotted wilt vi- nyza bonariensis) control in lucerne. In tos, A. and Grigulis, K. (2002a). Mecha- rus. Australian Journal of Agricultural ‘Result 1991’, pp. 51-2. (Weed Research nisms of resistance of Mediterranean Research 12, 239-46. and Demonstration Unit, Agricultural annual communities to invasion by Co- Hussey, B.M.J., Keighery, G.J., Cousens, Research and Veterinary Centre, Or- nyza bonariensis, effects of native func- R.D., Dodd, J. and Llloyd, S.G. (1997). ange, Australia). tional composition. Oikos 99, 338-46. ‘Western weeds’, p. 94. (Plant Protec- Molfino, R.H. (1947). Argentine plants Prieur-Richard, A.H., Lavorel, S., Linhart, tion Society of Western Australia, West- which produce changes in the char- Y.B. and Dos Santos, A. (2002b). Plant ern Australia). acters and properties of milk and its diversity, herbivory and resistance of a Kempen, H.M. (1988). Horseweed (mare- derivatives. Comunicacion del Instituto plant community to invasion in Medi- stail) and fl ax-leaf fl eabane, their identi- Agrario Argentino (Argentinian Agrar- terranean annual communities. Oecolo- fi cation and control. Proceedings of the ian Institute Report) 7, 23-34. gia 130, 96-104. California weed conference. 1988. (40), Moreira, M.S., Nicolai, M., Carvalho, S.J.P. Procopio, S.O., Ferreira, E.A., Silva, E.A.M., p. 179-81. Paper presented at a confer- and Christoffoleti, P.J. (2007). Glypho- Silva, A.A., Rufi no, R.J.N. and Santos, ence on ‘Education and communica- sate-resistance in Conyza canadensis and J.B. (2003). Leaf anatomical studies in tion–the keys to the future’, January 18- C. bonariensis. Planta Daninha 25, 157- weed species widely common in Bra- 21, 1988, Sacramento, California. 64. zil. III – Galinsoga parvifl ora, Crotalaria Kempen, H.M. and Graf, J. (1981). Weed Norman, M.A. and Fuerst, E.P. (1997). In- incana, Conyza bonariensis and Ipomoea seed production. Proceedings of the West- teractions of cations with paraquat in cairica. Planta Daninha 21, 1-9. ern Society of Weed Science 34, 78-81. leaf sections of resistant and sensitive Pruski, J.F. (2006). Conyza sumatrensis var. Khan, R.A., Bukhari, I.A., Nawaz, S.A. biotypes of Conyza bonariensis. Pesticide leiotheca (Compositae: Asteraceae), a and Choudhary, M.I. (2006). Acetylcho- Biochemistry and Physiology 57, 181-91. new combination for a common neo- linesterase and butyrylcholinesterase Norman, M.A., Smeda, R.J., Vaughn, K.C. tropical weed. NOVON 16, 96–101. inhibitory potential of some Pakistani and Fuerst, E.P. (1994). Differential Qasem, J.R. (2002). Plants as sources of medicinal plants. Journal of Basic and movement of paraquat in resistant and natural herbicides against branched Applied Sciences 2, 7-10. sensitive biotypes of Conyza. Pesticide broomrape (Orobanche ramosa L.). In Kong, L.D., Abliz, Z., Zhou, C.X., Li, L.J., Biochemistry and Physiology 50, 31-42. ‘Allelopathy, from molecules to ecosys- Cheng, C.H.K. and Tan, R.X. (2001). Gly- Olano, I., Alonso Paz, E., Cerdeiras, M.P., tems’. pp. 153-82. (Science Publishers, cosides and xanthine oxidase inhibitors Fernandez, J., Ferreira, F., Moyna, P., Inc., Enfi eld, USA). Plant Protection Quarterly Vol.22(4) 2007 131 Randall, R.P. (2002). ‘A global compendi- Thebaud, C., Finzi, A., Affre, L., Debussche, in the Roma region. Proceedings of a um of weeds’. p. 187. (RG and FJ Rich- M. and Escarre, J. (1996). Assessing why national workshop on fl eabane held at ardson, Melbourne). two introduced Conyza differ in their Queensland Department of Primary In- Razaq, Z.A., Vahidy, A.A. and Ali, S.I. ability to invade Mediterranean old dustries and Fisheries in Toowoomba (1994). Chromosome numbers in Com- fi elds. Ecology 77, 791- 804. on 25th February 2004, p. 27. positae from Pakistan. Annals of the Mis- Thorn, S. (2004). Fleabane – implications Werth, J. and Walker, S. (2007). Tillage ef- souri Botanical Garden 81, 800-8. for current farming systems in Goondi- fects on fl eabane emergence Proceed- Regehr, D.L. and Bazzaz F.A. (1976). Low windi region. Proceedings of a national ings of a fl eabane workshop held at temperature photosynthesis in suc- workshop on fl eabane. 25th February Queensland Department of Primary cessional winter annuals. Ecology 57, 2004, DPI&F, Toowoomba, Queensland. Industries and Fisheries in Toowoomba 1297–303. pp. 25-26. on 7th February 2007, pp. 22-23. Richardson, F.J., Richardson, R.G. and Tothill, J.C. and Berry, J. (1981). Cool season White, G.A., Willingham, B.C., Skrdla, Shepherd, R.C.H. (2006). ‘Weeds of the weed invasion of improved subtropi- W.H., Massey, J.H., Higgins, J.J., Cal- south-east, an identifi cation guide for cal pastures. Proceedings of the Sixth houn, W., Davis, A.M., Dolan, D.D. and Australia’. (R.G. and F.J. Richardson, Australian Weeds Conference, Volume Earle, F.R. (1971). Agronomic evalua- Melbourne). 1, eds. B.J. Wilson and J.T Swarbrick, tion of prospective new crop species. Roy, B., Popay, I., Champion, P., James, T. pp. 29-33. (Queensland Weed Society, Economic Botany 25, 22-43. and Rahman, A. (1998). ‘An illustrated Toowoomba, Australia). Whittet, J.N. (1968). ‘Weeds’, 2nd edition. guide to common weeds of New Zea- Tsutomu, H., Taeko, Y., Rieko, Y., Yukihiko, (Government Printing, Sydney). land’, p. 62. (New Zealand Plant Protec- I., Muneto, M., Kazufumi, Y., Isao, A., Wilson, B.J., Hawton, D. and Duff, A.A. tion Society, Canterbury, NZ). Sansei, N., Tadaka, N., Masao, Y. and (1995). ‘Crop weeds of northern Aus- Shaaltiel, Y., Chua, N.H., Gepstein, S. and Takuo, O. (1991). Inhibitory effects of tralia’. p. 61. (Department of Primary Gressel, J. (1988). Dominant pleiotropy galloylated fl avonoids on xanthine oxi- Industries, Queensland). controls enzymes co-segregating with dase. Planta Medica 57, 83-4. Wu, H. and Walker, S. (2004). Flaxleaf fl ea- paraquat resistance in Conyza bonarien- Tzakou, O., Vagias, C., Gani, A. and Yan- bane, a diffi cult-to-control weed in dry- sis. Theoretical and Applied Genetics 75, nitsaros, A. (2005). Volatile constituents land cropping systems associated with 850-56. of essential oils isolated at different zero-tillage. Australian Grain, northern Shaaltiel, Y. and Gressel, J. (1987). Kinetic growth stages from three Conyza spe- focus iii-v, November-December 2004. analysis of resistance to paraquat in cies growing in Greece. Flavour and Fra- Wu, H., Walker, S., Rollin, M.J., Tan, D.K.Y. Conyza – evidence that paraquat tran- grance Journal 20, 425-8. and Werth, J. (2007). Germination, per- siently inhibits leaf chloroplast reac- Urbano, J.M., Borrego, A., Torres, V., Jimen- sistence and emergence of fl axleaf fl ea- tions in resistant plants. Plant Physiology ez, C., Leon, J.M. and Barnes, J. (2005). bane (Conyza bonariensis (L.) Cronq.). 85, 869-71. Glyphosate-resistant hairy fleabane Weed Biology and Management 7, 192-9. Sida, O. (2003). Conyza triloba, new to Eu- (Conyza bonariensis) in Spain. Proceed- Wu, H., Walker, S.S., Taylor, I.N. and Rob- rope, and Conyza bonariensis, new to the ings of Weed Science Society of America inson, G. (2006). Biology and manage- Czech Republic. Preslia 75, 249-54. 45, 394. ment of fl axleaf fl eabane (Conyza bon- Silveira, H.L., Caixinhas, M.L., Leitao, A. Urdampilleta, J.D., Amat, A.G. and Bidau, ariensis L. Cronq.). Proceeding of the and Gomes, R. (1988). Evolution of ac- C.J. (2005). Karyotypic studies and mor- 15th Australian Weeds Conference, eds tual and potential weed fl ora after soil phological analysis of some reproduc- C. Preston, J.H. Watts and N.D. Cross- solarisation. VIIIe Colloque International tive features in fi ve species of Conyza man, pp. 137-40. (Weed Management sur la Biologie, l’Ecologie et la Systema- (Astereae, Asteraceae) from northeast- Society of South Australia, Adelaide). tique des Mauvaises Herbes 1, 59-69. ern Argentina. Contenido del Volumen Wurzell, B. (1994). A history of Conyza in Singh, S., Dube, N.K., Tripathi, S.C. and 40, 91-9. London. BSBI News, London, 65, 34–8. Singh, S.K. (1984). Fungitoxicity of Vaughn, K.C., Vaughan, M.A. and Camill- Xie, F.Y. and Yao, L.X. (1989). A study on some essential oils against Aspergillus eri, P. (1989). Lack of cross-resistance of Dorylus orientalis Westwood. Insect fl avus. Indian Perfumer 28, 164-6. paraquat-resistant hairy fl eabane (Co- Knowledge 26, 291-3. Souza, M.C., Siani, A.C., Ramos, M.F.S., nyza bonariensis) to other toxic oxygen Ye, B., Faltin, Z., Ben-Hayyim, G., Eshdat, Menezes-de-Lima Junior, O. and Hen- generators indicates enzymatic protec- Y. and Gressel, J. (2000). Correlation of riques, M.G.M.O. (2003). Evaluation of tion is not the resistance mechanism. glutathione peroxidase to paraquat/ anti-infl ammatory activity of essential Weed Science 37, 5-11. oxidative stress resistance in Conyza oils from two Asteraceae species. Phar- Wagner, W.L., Herbst, D.R. and Sohmer, determined by direct fl uorometric as- mazie 58, 582-6. S.H. (1999). Manual of the fl owering say. Pesticide Biochemistry and Physiology Somervaille A. and McLennan B. (2003). plants of Hawaii. Revised edition, (two 66, 182-94. ‘The 2nd fallow weed management volumes). Bernice P. Bishop Museum Ye, B. and Gressel, J. (2000). Transient, guide’. (Conservation Farmers Inc., special publication. p. 288. (University oxidant-induced antioxidant transcript Toowoomba). of Hawaii Press/Bishop Museum Press, and enzyme levels correlate with greater Taylor, F. (2007). Nufarm research with Honolulu) oxidant-resistance in paraquat-resistant fl eabane control options. Proceedings Walker, S. and Robinson, R. (2007). Nation- Conyza bonariensis. Planta 211, 50-61. of a fl eabane workshop held at DPI&F al screening for glyphosate resistance Zelaya, I.A, Owen, M.D.K. and Van Ges- in Toowoomba, 7 February 2007, p. 47. in fl eabane. Proceedings of a fl eabane sel, M.J. (2007). Transfer of glyphosate Terzioğlu, S. and Anşin, R. (2001). A choro- workshop held at Queensland Depart- resistance: evidence of hybridisation in logical study on the taxa naturalized in ment of Primary Industries and Fish- Conyza (Asteraceae). American Journal of the eastern black sea region. Turkish Jour- eries in Toowoomba on 7th February Botany 94, 660-73. nal of Agriculture and Forestry 25, 305-9. 2007, pp. 32-33. Zinzolker, A., Kigel, J. and Rubin, B. (1985). Thebaud, C. and Abbott, R. (1995). Char- Walker, S. and Wu, H. (2006). Knocking out Effects of environmental factors on the acterization of invasive Conyza species fl axleaf fl eabane. Australian grain, north- germination and fl owering of Conyza (Astereae) in Europe, quantitative trait ern focus i-iii. (July-August 2006). albida, C. bonariensis and C. canadensis. and isozyme analysis. American Journal Ward, L. and Hamilton, R. (2004). Flea- Phytoparasitica 13, 229-30. of Botany 82, 360-8. bane – a declining problem on ‘Callitris’