Fallopia convolvulus
(black bindweed)

F. convolvulus is a weedy species of gardens, cultivated fields, open habitats, orchards, non-crop areas, waste areas, and disturbed sites. It is well-adapted to a wide range of climatic conditions and soils. This species is a prolific seed producer and has the potential to produce up to 30,000 seeds/plant. Seeds can be dispersed by farm machinery, and water. It is also a common contaminant of wheat and other cereal crops.

F. convolvulus is often a serious weed in cereals, vegetables and horticultural crops (FAO, 2015). Currently, it is listed as invasive in the Dominican Republic, Cuba, Australia, New Caledonia, and New Zealand (Webb et al., 1988; MacKee, 1994; Wilson, 2008; Acevedo-Rodriguez and Strong, 2012), but it is also ranked as a serious weed in 20 crops in more than 41 countries around the world (Holm et al., 1991).

F. convolvulus is native to Eurasia, although due to its plasticity it occurs in most regions of the world. In Europe and North America it grows everywhere that crops are cultivated, but is less frequent in the south (Franzini, 1982). In Canada, it is reported as one of the most abundant weeds, occurring in 60-80% of all fields in the provinces of Alberta, Manitoba, Saskatchewan and Prince Edward Island (Hume et al., 1983). It is found throughout South America. In Africa it occurs in North Africa, on the east coast and in South Africa. In Asia, its geographical distribution ranges from Japan to Iran, down to India and into Indonesia. F. convolvulus can also be found in Australia and New Zealand. It is not common in the humid tropics, and in warm areas, it is more often found at high altitudes or in cooler valleys (Holm et al., 1991).

F. convolvulus is most common on arable land, but it can also be found on waste ground, in thickets, on roadsides, along fences, and occasionally in pastures and on river banks (Hume et al., 1993). Because of its deep root system, it is rather unaffected by drought or low nitrogen levels. Nevertheless, high nutrient levels promote the growth and abundance of F. convolvulus (Bazdyrev et al., 1984; Mahn, 1984; Pulcher-Häussling and Hurle, 1986; Borowiec and Kutyna, 1988; Bräutigam, 1995). According to Karczmarczyk et al. (1983), who investigated the influence of irrigation on potato, sugar-beet and the weeds associated with these crops, F. convolvulus predominates on non-irrigated field plots. Haas and Streibig (1982) and Haman and Peeper (1983) reported that growth of F. convolvulus is stimulated by shading.

While in northern areas it is found in warm and well-drained locations, in hotter countries it is present on moist shady sites and at high altitudes. In China, F. convolvulus is found in thickets in valleys and along stream banks, at 100-3600 m (Flora of China Editorial Committee, 2015). In Pakistan, as well as being a weed on cultivated land, it is recorded in crevices in moist, shady places and at 1500-3500 m altitude (Flora of Pakistan Editorial Committee, 2013). 

A list of crops in which F. convolvulus is, or could be, a problem weed includes almost every crop of the temperate zone. Worldwide, F. convolvulus is most troublesome in cereals, but it may also cause yield losses in potatoes, sugarbeet and vegetables, as well as vineyards and orchards. According to Holm et al. (1991), it is a weed of 25 crops in 41 countries and in 20 crops of these countries it is ranked as a serious weed.

Genetics

F. convolvulus is polyploid and has a chromosome count of 2n = 40 (Mulligan, 1957, 1960; Clapham et al., 1962).

Reproductive Biology

Flowers of F. convolvulus are bisexual and self-compatible (Mulligan and Findlay, 1970). Each flower produces a single achene. In Asia, this species has been recorded flowering from July to September (FAO, 2015). In Europe, flowering plants can be found throughout the summer till mid-autumn (Hanf, 1982). As a result of the indeterminate flowering habit of F. convolvulus, flowers, immature seed and mature seed may be found at the same time on a single plant.

Longevity

F. convolvulus is a fast-growing herb that behaves as annual and perennial herb. It has a large, fibrous root system which may reach down as far as 80 cm in the soil (Kutschera, 1960), enabling it to evade dry conditions.

Physiology and Phenology

According to Hanf (1982), a single plant of F. convolvulus produces 100 to 1000 seeds. Grown without competition, Stevens (1932) reported fecundity of 11,900 seeds per plant, and Forsberg and Best (1964) obtained up to 30,000 seeds from plants that emerged early in the growing season. The seeds possess a deep primary dormancy for several months when mature (Zwerger, 1987, 1993) due mostly to the hard pericarp, which limits gas and water exchange, and acts as a barrier to germination (Ransom, 1935; Timson, 1966). Under field conditions, most seeds germinate in their first year (Chepil, 1946), but they may remain viable in the soil for several years (Holm et al., 1991). Chippendale and Milton (1934) found viable seeds of F. convolvulus after approximately 22 years in the soil under pasture.

Seedlings emerge throughout the growing season. They normally germinate at depths in the soil between 6 and 51 mm, although research has shown that seeds buried as deep as 19 cm can germinate (Forsberg and Best 1964). Light is not required for germination. Seeds germinate at temperatures between 2°C and 30°C, with maximum germination rates occurring between 5°C and 15°C.

Environmental Requirements

F. convolvulus occurs on a wide range of soil types (Hume et al., 1983), but according to Paatela and Erviö (1971) it is less common on peaty soils. In field observations in Finland, F. convolvulus was more abundant in clay than in coarse mineral or organic soil (Erviö et al., 1994). Higher rates of F. convolvulus emergence are recorded on soils with a high clay content. In field experiments in Poland, F. convolvulus predominated on plots fertilized with nitrogen plus calcium (Borowiec et al., 1995). However, Zwerger (1990) could only find a positive effect of nitrogen fertilization on seed production at low densities of this weed.

At higher weed densities, the effect of intraspecific competition became more important than nitrogen supply. Sirbu and Slonovschi (1989) found that nutrient reserves of F. convolvulus seeds increased with increasing phosphate fertilization. In a study concerning the distribution of several common weeds in Denmark, decreasing potassium content in the soil appeared to favour the occurrence of F. convolvulus (Andreasen and Streibig, 1990; Andreasen et al., 1991). According to Hanf (1982), it is one of the most frequent weeds on soils with a low pH.

Shade usually suppresses the growth of black bindweed (Haman and Peeper 1983), but in hotter countries it can be found in moist shady places and crevices (Flora of Pakistan Editorial Committee, 2013).

Insects that have been cited as using F. convolvulus as a host are Gastrophysa polygoni (Forsberg, 1955; Kjaer and Elmegaard, 1996), Coleophora therinella and C. peribenanderi (van der Wolf, 1992). F. convolvulus may serve as a habitat for a number of viruses, insects (Mamestra (Noctuidae) and Pegomyia (Anthomyiidae)), nematodes (species of Heterodera and Meloidogyne) and fungi (species of Ustilago, Puccinia and Peronospora). A review of arthropod natural enemies in Canada and Europe was presented by Hume (1983). 

In a study on the internal and surface-dwelling pathogenic fungi of seeds of the 30 most widespread weed species in Lithuania, Grigaliunaite and Kacergius (1995) found that F. convolvulus seeds were the least damaged of all weeds investigated.

Prior to flowering, F. convolvulus may be mistaken for Convolvulus arvensis, as both have twining greenish stems and leaves of similar shape. In contrast to F. convolvulus, C. arvensis is a deep-rooted perennial with extensive creeping white roots and rhizomes, blunt-tipped leaves and large funnel-shaped pink or white flowers. It has no ochrea or sheathing stipules as in F. convolvulus.

Two further Fallopia species which could be confused with F. convolvulus in Canada (Hume et al. (1983): Fallopia cilinode and F. scandens. Both are perennials.  Fallopia cilinode has bristles at the base of the sheath, leaves with narrower spacing between the basal lobes and achenes that are shiny and smooth. The flowers of F. scandens are long-stalked. It has a strong, winged calyx and smooth, shiny achenes.

F. convolvulus is also closely related to Fallopia dumetorum and F. dentate-alata, but in both these species the pedicel is much longer (up to 10 mm long) and articulated above the middle (Flora of Pakistan Editorial Committee, 2013).

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Cultural Control

According to Holm et al. (1991), tillage implements and rotations have only limited success in controlling F. convolvulus because of its large seedbank, the ability of seeds to emerge from great depth, the persistent emergence of new seedlings throughout the growing season and the large quantities of seeds produced by the plants.

Nevertheless, there are several methods suggested which could be used to reduce possible yield losses caused by this weed. Koch (1964) observed a stimulation in emergence of F. convolvulus by harrowing, which could be taken advantage of in the control of this weed in cereal cultivation. Gruenhagen and Nalewaja (1969) and Messersmith and Nalewaja (1969) stated that higher seeding rates of the crop result in a reduction of relative yield losses through competition of F. convolvulus in wheat or flax. Moreover, Smith (1980) found out that a significant reduction of F. convolvulus could be attained by discing after barley harvest.

Different results have been published regarding the effects of tillage techniques as a means for weed control. Thompson et al. (1984) and Dessaint et al. (1993) concluded that no-tillage cultivation or reduced tillage resulted in increasing densities of F. convolvulus in comparison to conventional tillage, whereas Hoffman-Kakol et al. (1982) observed a reduction in the relative abundance of F. convolvulus in directly drilled maize after rye. Nielsen and Pinnerup (1982) also reported a decline in F. convolvulus populations caused by reduced cultivation in spring barley.

Although effective for the control of other weeds, harrowing in the dark showed no significant influence on emergence of F. convolvulus seedlings in comparison to daylight harrowing in Swedish field trials (Ascard, 1992).

According to Rajczyova (1978), monocultures of winter wheat and spring barley lead to an increase in F. convolvulus incidence.

Biological Control

Adkins and Sowerby (1996) revealed that the weed Parthenium hysterophorus has allelopathic potential against P. covolvulus. They used leachate from the leaves of P. hysterophorus to depress germination and seedling growth of F. convolvulus and several other weeds.

In a search for potential biological control agents for weeds, species of Botrytis were isolated from seedlings of F. convolvulus infected with pathogenic fungi in Canada (Mortensen and Molloy, 1993). In Argentina, the fungus Puccinia polygoni-amphibii was found to cause sufficient damage to warrant investigation as a biocontrol agent against F. convolvulus (Dal-Bello and Carranza, 1995).

Chemical Control

A considerable number of selective herbicides sprayed alone, in mixtures either pre- or post-emergence have been used to control F. convolvulus: aclonifen, atrazine, aziprotryne, benfluralin, benazolin, bentazone, bifenox, bromoxynil, chloramben, chlorbromuron, chloridazon, chlorsulfuron, chlorthal-dimethyl, clopyralid, cyanazine, cycloate, 2,4-D, desmedipham, dicamba, dichlorprop, dinitramine, diphenamid, ethalfluralin, ethofumesate, fluorochloridone, fluroxypyr, glufosinate-ammonium, haloxyfop, ioxynil, isopropalin, linuron, lenacil, MCPA, MCPB, mecoprop, metamitron, metolachlor, metobromuron, metsulfuron, metribuzin, napropamide, oryzalin, oxadiazon, oxyfluorfen, pendimethalin, phenmedipham, picloram, prometryn, propachlor, propyzamide, pyridate, sethoxydim, thifensulfuron, triasulfuron, tribenuron, trifluralin and triflusulfuron (Haas and Streibig 1982; Anderson et al., 1996; Fain, 1986; Nohl-Weiler and Hindersmann, 1986; Pimpini et al., 1986; Shalna and Melamed, 1986; Drazic et al., 1987; Kapros et al., 1988; Prochazka et al., 1988; Klingaman and Peeper, 1989; Milusher et al., 1989; Rapparini et al., 1989; Arends and Pegg, 1990; Lalova and Bogdanovske, 1990; Labza et al., 1990; Drazic and Glusac, 1991; Sysmans et al., 1991; Muller, 1992; Gvozdenovic-Varga et al., 1992; Meinlschmidt and Karch, 1992; Hallgren, 1993; Mitchell and Abernethy, 1993; Andersson, 1994; Rapparini, 1995, 1996; Bouma et al., 1996; Fields et al., 1996; Campagna and Rapparini, 1997; Toth and Peter, 1997).

Herbicide resistence has been reported for the following active ingredients: chlorsulfuron in Australia (Adkins et al., 1997); 2,4-D in Lithuania, Hungary and China (Aleksinas, 1984; Nemeth, 1985; Tu, 1989), 2,4-TB in Czechoslovakia (Bojas, 1987); MCPA in the former USSR and Hungary (Ryzhaya et al. 1984; Nemeth, 1985); metolachlor in the former USSR (Zuza, 1983; Veselovskii and Saulyak, 1984); metribuzin in Poland (Sawicka and Skalski, 1996); quinmerac in the UK (Boatman, 1991); simazine (Stryckers and van Himme, 1974); terbacil in Hungary (Nagy et al., 1978); and triazines in Czechoslovakia, Germany and the Netherlands (Valkova, 1975; Kees, 1988; van Oorschot, 1989).

Skorobogatova and Mirchinik (1985) revealed that the microbial metabolite citrin applied in wheat fields could decrease F. convolvulus incidence markedly, with negligible effects on wheat growth and yield. Gleason and Case (1986) showed that the algicide cyanobacterin inhibited the growth of F. convolvulus when sprayed onto the leaves of 1- to 2-week-old plants. Bryan et al. (1995) reported that a monic acid derivative of pseudomonic acid (derived from compounds produced by Pseudomonas fluorescens) was active against a range of broadleaved weeds, including F. convolvulus, in field trials performed in Canada. Barley was not affected by the monic acid derivative, although unacceptable damage to wheat did occur.

03/06/15 Updated by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA