Convolvulus arvensis
(bindweed)

C. arvensis, commonly known as bindweed, is a climbing herbaceous perennial native to Eurasia. This species is present in most parts of the world where it has been accidentally introduced as a contaminant of both agricultural and horticultural seed. C. arvensis produces a long lived root system and up to 500 seeds per plant. This species can grow very rapidly where it competes with native vegetation and agricultural and horticultural crops for nutrients, moisture, light and space. As a result, neighbouring plants may become smothered leading to a decrease in biodiversity and a reduction in crop yield. Control of this species is difficult due to the longevity of seeds in the soil bank (up to 20 years) and the ability of small fragments of rhizome to produce new shoots.

C. arvensis is native to Eurasia and is widely distributed in temperate and tropical regions throughout the world. C. arvensis may be found between 60°N and 45°S (Discover Life, 2016). It should be noted that its non-appearance in the accompanying "Distribution Table" is not a firm indication of its absence in a country. Rather, it is an indication that the literature that has been surveyed for this Compendium has not revealed a record of its presence.

C. arvensis is generally present all over the world, but it is not a major weed in most of these areas (Holm et al., 1977). C. arvensis produced a large number of seed which can remain viable for up to 20 years. These seeds are dispersed locally by water but they may also accidentally be introduced with the movement of seedstocks in commerce, and by clinging to mud on farm vehicles. As such, it is likely that the distribution of this species is likely to increase.

C. arvensis occupies disturbed and cleared ground. It is a major weed of field crops, (e.g. in wheat, barley, maize, legumes and sugar beet), of pastures and of horticulture (in vegetables, vineyards, and tree crops).

Annual crops such as cereals and grain legumes are particularly susceptible, and it is also widely reported as a troublesome weed in vineyards. Holm et al. (1977) also list C. arvensis as a weed of sugarbeet, cotton, tobacco, tea, potato, orchards, pineapples, vegetables, flax and lucerne.

Genetics

C. arvensis has been reported as having a chromosome number of 2n=24, 48, 50, 78 (IPCN Chromosome Reports, 2015).

Reproductive Biology

C. arvensis reproduces by producing seeds which may remain dormant in the soil for longer periods of time (20 years or more) (Holm et al., 1977; Americanos, 1994). It has been suggested that one plant may produce up to 500 seeds (Texas Invasives, 2016). Plants can also spread vegetatively from underground rhizome. It has been reported that a single plant may spread outward more than three meters in one growing season (National Parks Service, 2016). It is possible for root fragments as small as 5 cm to regenerate and produce new shoots (Texas Invasives, 2016).

Physiology and Phenology

Seeds germinate throughout the year if moisture is adequate but there are peaks of germination in spring, early summer and autumn. Plants grow rapidly as the weather becomes warmer, developing 15-20 leaves in the first month and an extensive root system (to a depth of 2 m) within about 7 months, which enables plants to persist despite cultivation and moisture stress. Plants may not flower in the first year but develop numerous lateral roots. Aerial growth dies off in autumn with the onset of cold weather and new growth from roots and crowns occurs in spring, with plants flowering from late spring through summer and sometimes into autumn. Seed set is variable and favoured by dry, sunny conditions; in cool weather or on waterlogged soil flowering is restricted and fruit often contain no viable seed (Parsons and Cuthbertson, 1992). C. arvensis has 'hard' seeds which, when fresh, require scarification and later require alternating temperatures. A large proportion of seeds will remain dormant in the soil seed bank (Texas Invasives, 2016).

C. arvensis produces a deep perennial root system with the ability to compete vigorously with crops for moisture and nutrients.

Environmental Requirements

C. arvensis has been reported to grow best in areas with moderate to good rainfall, with well drained soils, however, it can also tolerate periods of drought (Texas Invasives, 2016).

A considerable range of species are hosted by C. arvensis, many of them highly polyphagous (Mohyuddin, 1969a; Mohyuddin, 1969b; Baloch, 1974). This range of natural enemies must have some effect on control of the weed species within the original range of C. arvensis but their effect in controlling the competitiveness of the species does not appear to be well documented. There are several lists of European natural enemies of C. arvensis and evaluations of their potential as biological control agents (Rosenthal, 1980; Rosenthal and Buckingham, 1982; Wang and Kok, 1985). Toth and Cagan (2005) established an extensive list of organisms associated with the family Convolvulaceae worldwide and their potential as biological control agents. The List of Natural Enemies comprises species specialized on Convolvulaceae, but is not exhaustive.

Human food and beverage

• Leaves (for beverage)

Materials

• Dyestuffs

Medicinal, pharmaceutical

• Traditional/folklore

C. arvensis is similar in appearance to a number of species within the same genus. However, they can be distinguished from them fairly easily. For example, Convolvulus siculus has flower petals which are white or tinged bluish-lilac, about 6 mm long, C. farinosus has shorter petals 11-16 mm long, white in colour and tinged pinkish purple (the petals of C. arvensis grow to 20 mm) whilst C. sagittatus has much shorter petals 9mm long, white in colour to pink with purple centre (Bio-EAFRINET, 2016).

In the USA, Polygonum convolvulus may also be mistaken for C. arvensis however, its leaves are more pointed (National Park Service, 2016).

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.

Prevention

SPS Measures

C. arvensis is the subject of legislative control in several countries, which can include prohibitions on movement of the plant or produce contaminated by propagules of the plant (Genn, 1987). Parsons and Cuthbertson (1992) report that C. arvensis is declared as a proclaimed weed under legislation in several states in Australia. Depending on the legislation and category of declaration, the weed is subject to prohibition of sale and of movement of propagules (either on its own or as a contaminant of agricultural produce). It is also a weed banned from importation into Australia under national legislation. C. arvensis is considered a noxious weed in most of US states where it is prohibited in some of them (USDA-NRCS, 2016). It is also reported as a noxious weed in Kenya, Tanzania and Uganda (BioNET-EAFRINET, 2016).

Control

Cultural Control

Sheep and cattle (Sa'ad, 1967) readily graze C. arvensis. The weed does not generally appear to be a problem in areas frequently grazed by ruminants. If animals constantly remove the foliage, and thus the source of photosynthates for the perennial root system, it follows that the weed will be controlled in the longer term. However, there are reports that feeding on C. arvensis can adversely affect the health of stock (Parsons and Cuthbertson, 1992) but these appear to be very sporadic.

Cultivation / Mechanical Control

Phillips and Timmons (1954) carried out research which showed that C. arvensis could be eliminated within two seasons with careful cultivation practices, provided all aerial shoots were cut completely within 12 days of emergence. The weed could be eliminated with an average of 16 cultivations. Timmons and Bruns (1951) showed no practical advantage in cultivating deeper than 7.5-10 cm, but that the interval between cultivations could be lengthened to three weeks with deeper compared to shallow cultivation. Again, excellent control was obtained after two seasons (Holm et al., 1977). Shallow cultivation implements using normal cropping practices (one to two cultivations in autumn) do little but spread C. arvensis and increase the density of shoots emerging in spring (Schweitzer et al., 1988). Fragments of roots as small as 5 cm can regenerate (Swan and Chancellor, 1976). Therefore, if cultivation is to be used to successfully control the weed, it has to be frequent, thorough and persistent during the time that stems emerge. A minimum of two seasons appear to be necessary for a satisfactory outcome.

Biological Control

Rosenthal and Buckingham (1982) state that a European survey indicates that 140 species of insects, three mites and three fungi are associated with C. arvensis.

The pathogen Phomopsis convolvulus has been found to have some potential as a mycoherbicide for control of C. arvensis (Ormeno-Nunez et al., 1988; Vogelsgang et al., 1998; Morin et al., 1989).

In the 1970s, the US Department of Agriculture (USDA) initiated a programme for the biological control of field bindweed; two biological control agents have been released in North America so far. The gall mite Aceria malherbae (Acari: Eriophyidae) was released in Texas in 1989 and has been redistributed since in several US states and in Canada (Boldt and Sobhian, 1993; McClay et al., 1999). In heavily infested plants, the shoots are distorted and growth is severely stunted. However, establishment and impact under field conditions are variable and appear to depend on moisture levels. Effective control of C. arvensis with A. malherbae also requires additional management such as regular mowing and redistribution of mites. The bindweed moth Tyta luctuosa (Lep.: Noctuidae) was released in 1987. Establishment was reported from Colorado, Oregon, Utah and Washington (McClay and De Clerck-Floate, 2013; Pacific Northwest Moths, 2015) and reports from Oregon suggest that it has had a low impact (Andreas et al., 2015).

In 2008 a new programme was initiated and additional potential agents were selected for screening at CABI in Switzerland. Experiment found the flea beetle Longitarsus rubiginosus (Col.: Chrysomelidae) and Longitarsus pellucidus not suitable as a biocontrol agents and the agromyzid fly Melanagromyza albocilia (Dipt.: Agromyzidae) proved difficult to rear in the lab (open-field tests are necessary to further assess the host specificity of this fly). The defoliating moth Emmelia trabealis (Lep.: Noctuidae) and the tortoise beetle Hypocassida subferruginea (Col.: Chrysomelidae) were selected for preliminary open-field tests. However, results were of such study were inconclusive and need to be repeated and additional tests in the lab with critical test species (e.g. sweet potato) would be necessary. Given the presence of other defoliating herbivores on C. arvensis in North America, investigations on natural enemies that attack other parts of the plant would be more fruitful. Attacking the root system will be critical to the successful control of the plant.

Chemical Control

Control of seedling C. arvensis and shoots emerged from perennial rootstock is quite effective using a number of widely available herbicides at normal rates. For example picloram, 2,4-D, MCPA, dicamba and glyphosate (Wiese and Lavake, 1985; Westra et al., 1992; Matic and Black, 1994; USDA-FS, 2016). Trifluralin at relatively high rates also gives short-term control (Warner et al., 1974). Longer-term control of the perennial root system is much more difficult and only appears possible with high rates of herbicides such as glyphosate (Wiese and Lavake, 1985), imazapyr (Schoenhals et al., 1990; Heering and Peeper, 1991; Matic and Black, 1994) and picloram plus 2,4-D (Humburg et al., 1981; Alcock and Dickinson, 1974). Application of the latter two chemicals results in persistent soil residues over a considerable period, which restricts cropping. Personal communications and literature references indicate that programmes based on persistent use of 2,4-D or MCPA for at least 5 years also appears to have controlled the perennial root system. Herbicide efficacy appears to vary from region to region and may be due to differences in the relative susceptibility of clones of C. arvensis (Whitworth and Muzik, 1967; DeGennaro and Weller, 1984) or variations in climate between regions (Meyer, 1978; Sherrick et al., 1986). It also varies according to the timing of application of the herbicide (Davison and Bailey, 1974).

19/12/2016 Updated by:

Ghislaine Cortat, CABI-CH, Switzerland