Key weeds

Polygonum spp, Galeopsis spp., Poa annua, Elymus repens, Lamium spp., Chenopodium album, Stellaria media, Capsella bursa-pastoris, Veronica spp., Thlaspi arvense, Tripleurospermum inodorum, Senecio vulgaris, Urtica urens, Fumaria officinalis, Aethusa cynapium, Euphorbia helioscopia, Cirsium spp.

Increasing weed problems

None specific, mainly because of the access to linuron.

Approved herbicides:

Pendimethalin, linuron, glyphosate, fluazifob-p-butyl, cycloxydim, aclonifen,.

New herbicides under registration:

Tepraloxydim

Weed management systems

Conventional growers

Most growers use the following spraying strategy:

• pendimethalin 1200 g a.i. ha^-1 at seeding or false seedbed followed by glyphosate 540 g a.i. ha^-1 pre-emergence

• linuron 450 g a.i. ha^-1 + Sunoil 0.7 l ha^-1 post-emergence, weeds at the cotyledon stage

• linuron 450 g a.i. ha^-1 + Sunoil 0.7 l ha^-1 post-emergence, weeds at the cotyledon stage but before the two-true leave stage of carrots

• 3 passes of inter-row hoeing.

IP-growers

The IP concept for carrots is rather vague in Denmark and rely mostly on the grower's own conscience about pesticide use. However, the IP-growers try to save as much pesticide as possible, and some want to change their cropping system to single rows with 50 cm spacing to facilitate the use of band-application in the rows and hoeing between the rows.

Organic growers

All growers use a false seed bed techniques prior to sowing in mid May followed by pre-emergence flaming (50-80 kg gas ha^-1). Inter-row hoeing as close to the row as possible is also included and often 5 to 8 passes are conducted through the growing season. Weeds surviving physical weed control are removed by hand and that normally requires 100-300 hours ha^-1 of hand weeding. Weed beds for 8-12 persons are normally used for that purpose.

Relevant cultural practices:

• sowing time: early production from April 1st to May 15th; carrot for storage from May 1st to May 31st
• harvest time: early production from late June to the end of August; carrot for storage from the beginning of September to the end of October
• row distance: 30-70 cm (narrow distance for early production and when drilled on flat field surface; wide distance for storage carrot and when drilled ridges
• maybe 70-80 % of carrot area is sown on 20-30 cm high ridges, and rows are normally band rows (3-5 cm wide)
• plant density 30-110 plants/row-metre depending on the row distance, variety and the purpose of use of the yield

The most important weeds

• Chenopodium album, Stellaria media and Elymus repens because of their high frequency

• Viola arvensis, Matricaria matricariodes, M. inodora, Galeopsis spp. and Poa annua because of their tolerance to some herbicides

• Polygonum aviculare, Fallopia convolvulus and Galium spurium because of their high competitiveness, their harmful at harvest and their tolerance to some herbicides

• Sonchus arvensis in some fields

Key weeds

• Chenopodium album, Viola arvensis, Polygonum aviculare, Elymus repens

Weeds becoming important

• Rorippa sylvestris (spread originally from nurseries to fruit and berry cultivation, now spreading also to vegetables and other row crops)

• Cirsium arvense (becoming more common as well as Sonchus arvensis because the sulfonylureas used in cereals do not control them as effectively as the phenoxy acids before)

• also Galeopsis spp. is probably becoming more common than before because aclonifen does not control it.

Authorised herbicides

pre-emergence:

• glufosinate-ammonium (Basta)

• diquat (Reglone)

selective herbicides against dicot weeds:

• linuron (Afalon-neste)

• aclonifen (Fenix)

•  metribuzin (Senkor)

selective herbicides against Elymus repens and other grasses:

• fluazifop-p-butyl (Fusilade 2000)

• propaquizafop (Agil 100 EC)

• quizalofop-p-ethyl (Targa Super 5 EC)

Herbicides under registration

• pendimethalin (Stomp)

• clethodim (Select) (for the control of Poa annua)

Main programmes of weed management

Conventional (carrot for storage)

• mineral soil:

1. pre-emergence application with linuron or aclonifen (often this application is NOT made)

2. application with a low dose of linuron or aclonifen at ½ true leaf stage of carrot

3. application with linuron or aclonifen+metribuzin at 2 true leaf stage of carrot

4. if needed, application with linuron or aclonifen+metribuzin at 3-4 true leaf stage of carrot

5. if needed, control of Elymus repens with fluazifop-p-butyl, propaquizafop or quizalofop-p-ethyl

6. tractor harrowing (and moving soil on the carrot root bases) in July-August

• organic soil:

1. pre-emergence application with glufosinate-ammonium, diquat, linuron or aclonifen (often this application is NOT made)

2. application with a low dose of linuron or aclonifen at ½ true leaf stage of carrot

3. application with linuron or aclonifen+metribuzin at 2 true leaf stage of carrot

4. application with linuron or aclonifen+metribuzin at 3-4 true leaf stage of carrot

5. if needed, control of Elymus repens with fluazifop-p-butyl, propaquizafop or quizalofop-p-ethyl

6. tractor harrowing (and moving soil on the carrot root bases) in July-August

Organic

1. preparing the field for sowing at least some days before sowing

2. flaming the weeds just before the emergence of carrot (on organic soil this is not possible because the soil burns!)

3. tractor harrowing from 3 to 5 times during season

4. hand weeding

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France (by Francois Villeneuve)

  Acreage: 17 000ha of carrots with 4 mean areas of production ( 98% treated with herbicides). Actually, we have an increase of acreage for organic carrot.

Growing system

For early fresh carrot
Sowing in November et December with harvest in May and June
Sowing in February for harvesting in July and August

Generally, fumigation with dichloropropene is used to control nematodes but the association dichloropropene with metam sodium is become more and more used.

For season carrot
Sowing in April and May for harvesting September to December
For Normandy and Brittany, fumigation with dichloropropene

For winter carrot
For Normandy, sowing in May and June for harvesting January to the end of March with straw for froze protection Fumigation with dichloropropene

For Aquitaine, sowing dates June and July for harvesting January to the beginning of March . Froze protection : ridging carrots and turning over

Weeds

West of France
The most important weeds are : Polygonum persicaria, Polygonum aviculare, Anagallis arvensis, Solanum nigrum, Senecio vulgaris,Fumaria officinalis, Matricaria spp., Stellaria media, Atriplex patula, Poa annua and Digitaria spp.

Key weeds: Polygonum spp., Stellaria media and Fumaria spp.

Aquitaine
Early carrots
The most important weeds are : Stellaria media and Poa annua

Season and winter carrots
The most important weeds are : Solanum nigrum, Chenopodium albun, Amaranthus spp;, and Digitaria spp.

Key weeds: Stellaria media and Solanum nigrum

For West of France
Postsowing - pre-emergence : linuron at the rate of 700g ia/ha
Post-emergence at the stage "3-leaves" metoxuron And if it is necessary selective grass killers.

For Aquitaine
The situation is more difficult. Generally, total herbicides are used in autumn.

Early carrot
For a sowing in November or December, at sowing metoxuron with linuron at a reduced rate (200 to 300g ia/ha) and in March metoxuron with linuron (200 to 300 ia/ha) and selective grass killers if it is necessary.

Season an winter caarot
For sowing in May, in post emergence metoxuron with linuron (200 to 300 ia/ha) For sowing in June and July, 1 or 2 applications of metoxuron at a reduced rate - 500 / 600 g ia/ha with linuron (200 to 300 ia/ha) at very young stage of weed. It is also necessary to make applications of cycloxydime or Fluazifop-p-butyl for grass-weed control.

The situation for organic farmers is not very clear, all use mechanical row-crop cultivation and also flame weeding pre-emergence.

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Germany (by Arnd Verschwele)

Crop surface: 9375 ha in 2000
Treated area (herbicide use): about 96 %
Relevant cultural practices (sowing and harvest time, row distance, plant density):
bank growing in 45-75 cm distance, mainly 50 cm, 1-2 cm distance within the row
sowing time: February to May (June for fresh consumption)
sowing depth: 3 cm
plant density is depending on purposes (fresh or industrial consumption): 100-250 plants/m₂
harvest time: end of May/June for bunches, October for storage carrots
growing period of early carrots: 12 to 15 weeks
growing period of summer carrots: 15 to 20 weeks
growing period of late carrots: 23 to 28 weeks

Most important weeds:
Monocots: ALOMY, AVEFA,APESV, POAAN
Dicots: CHEAL, URTUR, STEME, VERSS, SENVU

Key weeds, weeds are becoming important: no information available

Authorised herbicides: fluazifop-P-butyl, pendimethalin, glufosinate

Herbicides under registration: aclonifen, metribuzin

Main programmes of weed management both in conventional and organic farming systems: mechanical and thermal weed control measures are be used effectively as carrots emerge after a long time. Additionally carrots show a high competitiveness during the later growth stages. However, as mentioned above weeds are normally controlled by herbicides on almost the complete area.

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Greece (by Garifalia Economou)  

Authorized Herbicides for carrots

Dactal 75 WP (chrorthal dimethyl 75% WP)
Afalon WP (linuron 47.5% WP )
Gramoxone SL (paraquat 20% SL )
Herboxone 20 SL (paraquat 20% SL )
Paraquero 20 SL (paraquat 20% SL )
Parazone SL (paraquat 20% SL )
Quatrol SL (paraquat 20% SL )
Stomp 330 E (pendimethalin 33% EC)
Otilan EC (trifluralin 48% EC)
Treflan 48 EC (trifluralin 48% EC)
Triflluralin- Agan 48 EC (trifluralin 48% EC)
Trifluralin - Cyanamid 48 EC (trifluralin 48% EC)
Trifluralin- Veteerin 48 EC (trifluralin 48% EC)
Trifulex 48 EC (trifluralin 48% EC)
Triplen 48 EC (trifluralin 48% EC)
Targa 5 EC (quizalofop-P- ethyl 5% EC)
Sencor WG (metribuzin 70)

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Hungary (by Maria Torma)

Crop surface: 4500 ha (about 100% treated with herbicides)

Cropping system:
Sowing time: March
Harvesting time: 5-15 June (short vegetation period); 20-30 October (long vegetation period)
Row distance: 25-45 cm

The most important weeds: Echinochloa crus-galli, Setaria pumila, S. viridis, Amaranthus retroflexus, A. blitoides, Chenopodium album, C. hybridum, Hibiscus trionum, Fumaria schleicheri, Datura stramonium,Reseda lutea, Convolvulus arvensis

Authorised herbicides: trifluralin(ppi), linuron (pre, post), clorbromuron (pre, post), pendimethalin (pre), prometrin (pre, post), s-metholaclor (pre), fluorcloridon (pre), glifosinate-ammonium (pre)

Herbicide under registration: cletodim

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Italy (by Francesco Tei)

Acreage:13'000 ha

Weeds
The most important species are:
Daucus carota, Bifora radians, Convolvulus arvensis, Artemisia spp., Torilis spp., Scandix pecten-veneris, Chenopodium spp., Polygonum spp., Amaranthus spp., Portulaca oleracea and Ammi majus.
In some cropping areas the following weeds are becoming important: Cirsium arvense, Cuscuta europea, Rumex spp.

Reference: Montemurro & Tei, 1998.

Morocco (by Si Bennasseur Rzozi)

Crop surface in 1999-2000
The official total carrots acreage in Morocco is around 10 180 ha, 4 215 ha are produced in areas with large scale irrigation, and 5 965 ha are scattered around the country and are produced in areas with small scale irrigation. However, we believe that acreages are more than the number mentioned above, because of the difficulty for official regional agricultural administrations to take into account all carrot fields grown in different regions, and especially those situated in many remote areas of the country.
The total production for the 1999-2000 year was 209.510 tons; 108.770 tons in areas with large scale irrigation, and 100.740 tons in areas with small scale irrigation. Some 70 tons were exported during 1999-2000, among which 8 tons were certified organic.

Treated area
Official information on treated areas for carrots are lacking, and are difficult to obtain. Therefore we made a survey, which consisted on asking different Moroccan companies who sell herbicides for weed control in carrots, on the quantities sold during last year. According to this survey, which consisted on adding all quantities of herbicides sold during 2000-2001, the acreages of carrots treated with herbicides were more than 15 000 ha. This corroborates our comment regarding the underestimated official carrots acreages declared by the Ministry of Agriculture, Rural development and Forestry of Morocco.

Relevant cultural practices
Carrots are cultivated in all regions of Morocco. Carrots can be planted year around in Morocco, except during the cold period of December-January in regions situated far away from the cost to avoid undesirable seed production through bolting.
The crop is planted in a row spacing of 20 cm, the space between plants within the row is around 5-6 cm. Planting densities for carrots are always higher for the production oriented for processing, compared to those for carrots that will be consumed as a fresh legume. Farmers use direct drilling instead of transplanting to avoid the formation of forked carrots. Varieties used by most farmers in Morocco are mainly Nantes, Recelido, Racedalbar, Nandor, Favor and Ivor. Recently, farmers are starting to use hybrids such as Avenger, Caropak, Legend, Navajo, Flame, and Neptune.
Fields are usually irrigated prior to planting. However, excessive irrigation is avoided after planting to prevent the development of diseases that can cause seed rot. Carrot fields usually receive between 20 and 40 tons/ha of manure. However, additional fertilizers are applied by farmers at planting, at 4-5 leaf stage, and at the beginning of tuber formation.

The most important weeds
In Morocco, as in the other Mediterranean countries, the weed flora accompanying carrots is very rich in species (both grasses and broad-leaved weeds), but their composition is dependant on many factors. The main factors influencing weed composition in carrots are soil type, the climate of each growing season, the sowing period, and the cropping system. The key weeds belong to Apiaceae and Convolvulaceae families. The most important weeds accompanying carrots in Morocco are different depending on predominating soil type (Table 1). Cuscuta sp. is gaining more ground because of free movement of carrot seeds between different agricultural regions, and because many farmers still buy non certified seeds in the absence of law enforcement regarding seed quality and the presence of dangerous weed seeds in seed lots.

Table 1. The main weed species in carrot crop in Morocco in the dominant soil types. 

Other species can be found in carrot fields, but at lower densities, compared to those mentioned in Table 1. These are : Polygonum aviculare L., Polygonum persicaria L., Digitaria sanguinalis (L.) Scop., Setaria spp., Amaranthus spp., Chenopodium album L., Convolvulus arvensis L., Euphorbia spp., Solanum nigrum L., Polygonum aviculare L., Capsella bursa-pastoris, Poa annua, Urtica urens...

Authorized herbicides

There are few herbicides registered in Morocco (Table 2), and none are actually under registration.

Table 2. Authorized herbicides for carrots in the Morocco (2001)

Main programmes of weed management in Morocco
Carrot is slow-growing crop that suffers severe yield loss from weed interference. Therefore, most Moroccan farmers use the herbicides mentioned in Table 2. However, an integrated weed management program is always essential for carrots because all registered herbicides mentioned above do not control all weeds present ion carrot fields. The majority of farmers follow herbicide application by one, two or three inter-row hoeing. The number of hoeing depends on the soil type, the period of carrots growth, the cropping system practiced in the field, and on how much efficacy was obtained using the herbicide.
We also sensitise farmers not to plant carrots in fields heavily infested with weeds, especially perennials that are difficult to control.

 

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Poland (by Adam Dobrzanski )

Acreage: ca 30 000 ha, about 80% treated with herbicides (estimated)

1. early carrots (roots with leaves) sowing: April - harvest: June - July;
2. early harvest of roots: sowing: April - harvest: 15 July -15 August;
3. summer harvest for fresh market: sowing: 20-30 April - harvest: 15 August - 15 September;
4. late harvest for processing, fresh market and storage: sowing: 15 - 31 May , some cultivars even on the beginning of April - harvest: October.

• equal row spacing of 0.30 - 0.45 m between all rows;
• "flat beds" 1.35 m wide with 4 rows apart 0.27 -0. 30 m on beds;
• cultivation on "ridges" 0.45 or 0.675 m between ridges; on ridges 0.45 m one row of carrots is sown, and on ridges 0.675 cm - 2-3 rows.

The most important weeds
Broad-leaved weeds: Chenopodium album, Galinsoga parviflora, Capsella bursa-pastoris, Amaranthus retroflexus, Stellaria media, Lamium amplexicaule, Sinapis arvensis, Urtica urens, Polygonum persicaria, Fallopia convolvulus, Matricaria maritima sp. inodora, Chamomilla recutita (Matricaria chamomilla), Senecio vulgaris, Viola arvensis, Solanum nigrum, Galium aparine, Euphorbia helioscopia.
Grass weeds: Echinochloa crus-galli, Poa annua, Agropyron repens (Elymus repens).

Key weeds: Chenopodium album, Galinsoga parviflora, Fallopia convolvulus, Capsella bursa-pastoris, Echinochloa crus-galli, Amaranthus retroflexus.

Species are becoming an increasing problem: Galium aparine, Matricaria and Anthemis spp. (especially in "secondary infestation" - during second part of growing period), Rorippa sylvestris.

Damages and treshold density
It was found, that during 49 days after sowing fresh biomass of weeds could rich 18.1 t ha^-1 (mean over 12 years of observation). Weeds are the most competitive at the beginning of growing period. Namely, when carrots are cultivated without herbicides a delay of the first weeding for 15 days decreases the yield up to 26% (6-year mean) that is ca. 1.7% per each day of weed competition.
When the weeds are in the competition from emergence up to harvesting about 90% of losses is expected.

Critical period of weed competition
Carrots should be free of weeds at least 1/3 - 1/2 of vegetation period.
More research are necessary on this subject, because CP probably depends on cultivars, time of sowing and cultivation methods.

Graminicides for grass weed control (Echinochloa cruss-galli, Agropyron repens) as post-emergence application.

On the base of registered herbicides different weed control programmes are involved (e.g. before sowing trifluraline + post-emergence linuron or prometryne; pre-emergence glyphosate or diquat + post-emergence linuron; pre-emergence pendimethaline + post-emergence prometryne). It was found that it is possible to apply reduced rates of pre-emergence herbicides followed by single or split application of reduced rates of linuron. It is possible to increase post-emergence activity of prometryne and linuron with adjuvants (Atpol - parafin oil with emulsifier).
Pre-harvest interval: prometryne: 42 days; linuron: 70 days; propaqizafop: 28 days; fluazifop-P-buthyl, cycloxydim, quizalofop-P-tefuryl, quizalifop-P-ethyl: 30 days; diclofop-methyl, fenoxaprop-P-ethyl: 42 days; sethoxydim: 35 days; haloxfop-P, clethodim: 60 days.

Integrated weed menagement
The protection of carrots from weeds combines herbicides and agronomic techniques, mechanical interrow cultivation and some times suplemental hand weeding.
Flaming is not applied in Poland, because of lack of equipment. Herbicides play the most important role, particularly on large plantations.
Carrots for "baby food" is produced without herbicides.
In early carrots, grown under covers with perforated foil or non woven polipropylene herbicides are applied immediately after sowing only.
The experiments were conducted (1994-1996) in order to determine the effect of harrowing at night and in day light on weed infestation and herbicides efficacy in carrots. The effect of timing of seedbed preparation was very short and temporary. In general, the efficacy of herbicides was not influenced by day/night tillage. Our results show that timing of seedbed preparation could not be an alternative to other methods of weed control in carrots, especially herbicide treatment. However, it could help dimnish weed infestation, particularly at the beginning of growing period.

References

Anyszka Z., Dobrzanski A., Palczynski J. 1996. Weed control in carrots under non-woven polypropylene. Second Int.Weed Control Congress, Copenhagen,:1049-1052.

Anyszka Z., Dobrzanski A., Palczynski J. 1997. Carrots and weed response to reduced rates and split application of herbicides. 10^th EWRS Symposium, Poznan:151.

Anyszka Z., Dobrzanski A. 1998. Influence of reduced rates and split application of herbicides on weed control and on yield in carrots (Daucus carota L.) Vegetable Crops Research Bulletin, 49:49-61

Dobrzanski A.,1975. [ Chemical weed control in carrots plantation]. Biul. Warz., 18:91-112 (Polish with English summary).

Dobrzanski A., Anyszka Z. 1994. [Reaction of weeds and carrot (Daucus carota L.) on linuron and prometryne with adjuvant Atpol]. Biul. Warz. 42:65-75. (Polish with English summary).

Palczynski J., Dobrzanski A., Anyszka Z. 1996. The influence of seedbed preparation at night on weed infestation and herbicide efficacy in carrots. Second Int. Weed Control Congress, Copenhagen:1267-1272.

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Portugal (by Fatima Rocha)

Crop surface: 2500 ha to 4500 ha, depending on the climatic conditions of the year.

Treated area: In general all carrot crop produced is treated with herbicides. In some situations, herbicides are complemented with mechanical control.

Relevant practices: Carrot is directed seeded after a good preparation of the soil. Several ploughs are made before sowing in order to prepare a fine seed bed for seeds. This is particularly important for varieties with long roots. Then, after sowing the soil surface layer is slightly compacted. The interval between rows is if of 25 cm. The distance between plants is 7-15 cm. In general, to sow one hectare, 4-5 kg of seeds are needed, depending on the varieties. (1g contains 700-900 seeds). Germination is good at 20ºC. However, when seeds are soaked in water for a period of 24-48h, germination occurs in only a few days. Sowing occurs from February till September, depending on the geographical areas. Cold springs and hot summers do not favour this crop. So in the North, sowings occur in March, May and September; in the central regions, sowing takes place from February till November; in South, from August till February. Harvest is also different according to the regions: on North, harvest takes place from September till April; in the Central region, from June till April; in South, it takes place all over the year. Normally, after sowing, some plants are taken out when they reach 3cm high to prevent high densities. Acid soils are not adequate to this crop. Yield varies between 33-35 ton ha_-1.

The Most important weeds: (see Table 1).

Key weeds: (see Table 1).

Authorised herbicides: The registered herbicides in Portugal (until 26 October 2001) and the conditions of application are presented on Table 2.

Main programmes of weed management in conventional systems: Herbicides or herbicides together with mechanical control.

Main programmes of weed management in organic farming systems: mechanical control (irrelevant areas).

Selected references of the last 2-3 years:
ROCHA, F., CALHA, I. & GRAÇA, G. (1998). Boa Prática Fitossanitária no Combate a Infestantes de Culturas Hortícolas Herbáceas (GPP on Horticulture crops) . DGPC. 240pp. 7000 exs.
ROCHA, F., MACHADO, C., CALHA, I. & AFONSO, J. (2001). Uso de herbicidas en cultivos herbaceos de Primavera. In: Herbicidas. Bioquímica, Fisiologia y Usos.
De Prado, R., Jorrin, J. & Garcia-Torres, L. (eds). Kluver, Dordrecht (in publication). 

Susceptibility to the registered herbicides 

Cicloxydim
Susceptibility (S):

Scientific name	Portuguese name
Agrostis spp.	agrostis
Avena spp.	balancos
Digitaria sanguinalis	milhã-digitada
Echinochloa crus-galli	milhã-pé-de-galo
Hordeum spp.	cevadas
Lolium spp.	azevéns
Phalaris spp.	alpistas
Setaria verticillata	pega-saias
Setaria viridis	milhã-verde

Resistance (R): All dicotyledons species and:

Scientific name	Portuguese name
Cyperus spp.	junças
Poa annua	cabelo-de-cão
Cynodon dactylon *	grama
Paspalum paspalodes *	graminhão
Panicum repens	escalracho

- MS (moderate) 

Fluazifop-P-butyl
Susceptibility (S):

grasses (annual and vivaces)

Resistant (R): Dicotyledons, Cyperus spp. and Poa annua.

Setoxydim
Susceptibility (S):

Scientific name	Portuguese name
Alopecurus myosuroides	rabo-de-raposa
Avena spp.	balancos
Digitaria sanguinalis	milhã-digitada
Echinochloa crus-galli	milhã-pé-de-galo
Hordeum spp.	cevadas
Lolium spp.	azevéns
Phalaris minor	erva-cabeçinha
Setaria spp.	setárias
Cynodon dactylon	grama
Elymus repens	grama-francesa
Panicum repens	escalracho
Paspalum spp.
Pennisetum spp.
Phalaris arundinacea	caniço-malhado

 

Resistant (R): Dicotyledons and Poa annua

Prometrine
Susceptibility (S): Poa annua and:

Scientific name	Portuguese name
Amaranthus spp.	bredos
Chamaemelum spp.	margaças
Chenopodium spp.	quenopódios
Datura stramonium	figueira-do-inferno
Fumaria officinalis	erva-moleirinha
Ornithopus compressus	serradela-brava
Papaver rhoeas	papoila-das-searas
Poa annua	cabelo-de-cão
Polygonum persicaria	erva-pessegueira
Portulaca oleracea	beldroega
Solanum nigrum	erva-moira
Spergula arvensis	esparguta
Stellaria media	morugem-branca
Urtica dioica	urtiga-maior
Veronica spp.	verónicas

Resistant (R):

Scientific name	Portuguese name
Avena spp.	balancos
Bilderdykia convolvulus	corriola-bastarda
Cirsium arvense	cardo-das-vinhas
Convolvulus arvensis	corriola
Cynodon dactylon	grama
Cyperus esculentus	junçinha
Cyperus rotundus	junça
Digitaria sanguinalis	milhã-digitada
Echinochloa crus-galli	milhã-pé-de-galo
Galium aparine	amor-de-hortelão
Raphanus raphanistrum	saramago
Setaria spp.	setárias
Sinapis arvensis	mostarda-dos-campos
Torilis spp.	salseiras

Linuron
Susceptibility (S): Gramínean and annual dicot.

Scientific name	Portuguese name
Amaranthus spp.	bredos
Anagallis arvensis	morrião
Capsella rubella	bolsa-do-pastor
Chamaemelum mixtum	margaça
Chamomilla recutita	margaça-das-boticas
Chenopodium album	catassol
Chrysanthemum segetum	pampilho-das-searas
Coleostephus myconis	pampilho-de-micão
Digitaria sanguinalis(*)	milhã-digitada
Echinochloa crus-galli(*)	milhã-pé-de-galo
Lolium multiflorum	azevém
Lolium rigidum	erva-febra
Papaver rhoeas	papoila-das searas
Poa annua	cabelo-de-cão
Polygonum aviculare(*)	sempre-noiva
Portulaca oleracea	beldroega
Raphanus raphanistrum	saramago
Senecio vulgaris	tasneirinha
Setaria pumila(*)	milhã-amarelada
Sinapis arvensis	mostarda-dos-campos
Sonchus oleraceus	serralha-macia
Spergula arvensis	esparguta
Stellaria media	morugem-branca
Urtica urens	urtiga-menor

(*) -MS

Resistant (R)

Scientific name	Portuguese name
Agrostis stolonifera	erva-fina
Avena sterilis	balanco-maior
Convolvulus arvensis	corriola
Cynodon dactylon	grama
Cyperus esculentus	junçinha
Cyperus rotundus	junça
Datura stramonium	figueira-do-inferno
Elymus repens	grama-francesa
Fumaria officinalis	erva-moleirinha
Galium aparine	amor-de-hortelão
Paspalum paspalodes	graminhão
Polygonum lapathifolia	mal-casada
Ranunculus arvensis	patalôco
Rumex angiocarpus	língua-de-andorinha
Rumex conglomeratus	labaça-ordinária
Solanum nigrum	erva-moira
Vicia sativa	ervilhaca-vulgar

Pendimethalin
Susceptibility (S): gramínean and dico (annuals)

Scientific name	Portuguese name
Amaranthus blitoides	bredo
Amaranthus retroflexus	moncos-de-perú
Bilderdykia convolvulus	corriola-bastarda
Chenopodium album	catassol
Chenopodium opulifolium	couve-maltesa
Digitaria sanguinalis	milhã-digitaria
Echinochloa crus-galli	milhã-pé-de-galo
Fumaria officinalis	erva-moleirinha
Heliotropium europaeum	erva-das-verrugas
Mercurialis annua	urtiga-morta
Polygonum aviculare	sempre-noiva
Polygonum lapathifolium	mal-casada
Portulaca oleracea	beldroega
Setaria spp.	setárias
Solanum nigrum	erva-moira
Urtica urens	urtiga-menor

Resistant (R):

Scientific name	Portuguese name
Convolvulus arvensis	corriola
Cynodon dactylon	grama
Cyperus esculentus	junçinha
Cyperus rotundus	junça
Datura stramonium	figueira-do-inferno
Euphorbia exigua	ésula-menor
Euphorbia helioscopia	maleiteira
Paspalum paspalodes	graminhão
Raphanus raphanistrum	saramago
Sinapis arvensis	mostarda-dos campos
Compositae and cruciferae species

Table 1. Most important weeds on carrot crop

Scientific name	Portuguese name
Agrostis stolonifera	erva-fina
Alopecurus myosuroides	rabo-de-raposa
Amaranthus blitoides(*)	bredo
Amaranthus retroflexus(*)	moncos-de-perú
Amaranthus spp.	bredos
Anagallis arvensis	morrião
Avena sterilis	balanco-maior
Bilderdykia convolvulus	corriola-bastarda
Capsella rubella	bolsa-do-pastor
Chamaemelum mixtum	margaça
Chamaemelum spp.	margaças
Chamomilla recutita	margaça-das-boticas
Chenopodium album	catassol
Chenopodium opulifolium	couve-maltesa
Chenopodium spp.	quenopódios
Chrysanthemum segetum	pampilho-das-searas
Cirsium arvense	cardo-das-vinhas
Coleostephus myconis	pampilho-de-micão
Convolvulus arvensis	corriola
Cynodon dactylon	grama
Cyperus esculentus(*)	junçinha
Cyperus rotundus(*)	junça
Datura stramonium	figueira-do-inferno
Digitaria sanguinalis	milhã-digitada
Echinochloa crus-galli	milhã-pé-de-galo
Elymus repens	grama-francesa
Euphorbia exigua	ésula-menor
Euphorbia helioscopia	maleiteira
Fumaria officinalis	erva-moleirinha
Galium aparine	amor-de-hortelão
Heliotropium europaeum	erva-das-verrugas
Lolium multiflorum	azevém
Lolium rigidum	erva-febra
Mercurialis annua	urtiga-morta
Ornithopus compressus	serradela-brava
Panicum repens	escalracho
Papaver rhoeas(*)	papoila-das-searas
Paspalum paspalodes	graminhão
Paspalum spp.	graminhão
Phalaris arundinacea	caniço-malhado
Phalaris minor	erva-cabeçinha
Poa annua(*)	cabelo-de-cão
Polygonum aviculare(*)	sempre-noiva
Polygonum lapathifolium(*)	mal-casada
Polygonum persicaria(*)	erva-pessegueira
Portulaca oleracea	beldroega
Portulaca oleracea	beldroega
Ranunculus arvensis	patalôco
Raphanus raphanistrum(*)	saramago
Rumex angiocarpus	língua-de-andorinha
Rumex conglomeratus	labaça-ordinária
Senecio vulgaris	tasneirinha
Setaria pumila	milhã-amarelada
Setaria verticillata	pega-saias
Setaria viridis	milhã-verde
Sinapis arvensis	mostarda-dos-campos
Solanum nigrum(*)	erva-moira
Sonchus oleraceus	serralha-macia
Spergula arvensis	esparguta
Stellaria media	morugem-branca
Urtica dioica	urtiga-maior
Urtica urens	urtiga-menor
Veronica spp.	verónicas
Vicia sativa	ervilhaca-vulgar

(*)Key Weeds

Table 2. Registered herbicides (until 26^th October 2001)

Weeds	Active ingredient	Dose gha-1	Conditions of application
Grasses	cicloxidim	200	Post-emergence of crop and weeds.
Grasses	fluazifop-P- butyl	250	Post-emergence of crop and weeds.
Grasses	setoxydim	190-1120	Post-emergence of crop and weeds.
Dicots	prometrine	1000-1500	Pre or post-emergence.
Grasses and dicots	linuron	500-1000	Pre or post-emergence.
Grasses and dicots	paraquat	300-1100	Before sowing as a technique for preparation the seed bed. Only to control annual species)
Grasses and dicots	pendimethalin	1320	Pre-emergence.

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Slovenia (by Andrej Simoncic )

Acreage: about 400 (1998)

Planting system
Carrots is grown as a main crop.
The main production is the storage and processing carrots which is sown in February and March (depending on location) and machine harvested in June-September. Some carrots is sown also as an undercrop into cereals in January and February.

Weeds
The weed communities are commonly very rich in species (both grasses and broad-leaved weeds) and their composition is highly variable. It depends mostly on sowing period and the climate of growing area as well as on crop rotation.

Integrated Weed Management in carrots in Slovenia
1. Early seed bed preparation and control of emerged weeds by glyphosate, gluphosinate ammonium or diquat;
2. Pre-emergence treatment
3. Post-emergence treatment using linuron for broad-leaved weeds and split low-doses of grass herbicides.
4. Mechanical row crop cultivation commonly integrates chemical weed control even if causes troubles due to plant fragility and row distance.

 

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Spain (by Carlos Zaragoza)

MAIN WEEDS:

1. Northern Spain: 1800 ha (Segovia and Valladolid provinces): Chenopodium album, Sinapsis arvensis, Convolvulus arvensis, Cuscuta europaea, Amaranthus spp., Cirsium arvense, Tribulus terrestris.
2. Southern Spain: 2000 ha (Cadiz province): Cyperus rotundus, Convolvulus aravensis, Portulaca oleracea, Urtica dioica, Chenopodium album, Solanum nigrum (patches), Sorghum halapense (patches), Malva spp (increasing by metilbromide tolerance)

The most used is linuron pre and post-emergence (not allowed). Metoxuron was used until 2002 but is not registered anymore. In the South metilbromide is still used to control nematodes but is changing to DD + plastic (it provides certain weed control).
The registered and commercialized herbicides in 2002 are trifluraline (PPI, 0.57-1.15 kg m.a./ha), diquat (PRE, 0.3-0.8), linuron (PRE, 0.45-0.9), prometrine (PRE, 0.5-1), setoxidim (POST, 0.2-0.4).

OTHER CHARACTERISTICS:

Crop is always in sandy soils. In the South there are two main sowing times: September to harvest in January, and January to harvest in April (as in the North). But crop is found all year long on the field (except July - August). Irrigation is mainly by sprinklers. Plantation density: 330000 pl/ha. Tillage: subsoiling or mouldboard, harrowing, roto-tilling, table maker. Fertilization through irrigation. In the South most of the harvest is exported to UK. Level of production: 50 Tm/ha. Integrated production (including herbicides) rules are under study. Crop rotation: Usually cereal, potato, sunflower. Recomended: tomato, onion.

REFERENCE:

PARDO IGLESIAS A., 2001:Zanahoria. En F.NUEZ and G.LLACER. La Horticultura Española. Soc.Esp. de Ciencias Hortícolas. Mundiprensa libros S.A. Madrid. 247-250.

 

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Sweden (by Fredrik Fogelberg)

Crop surface (1999)
1 755 ha in total (canning, organic, conventional)
of which 128 ha organic
and 1627 ha conventional

Herbicide treated area: 1627 ha

Relevant cultural practices

- sowing in late March (southern Sweden) to early June

- plant density 50-80 plants per row metre

- single row often used in organic production

- in conventional production seeds often spread in a 65 mm band in the row; row distance 48 or 50 cm most common, some farmers use 70-75 cm row spacing when seeding on ridges

- harvest generally in September to November for storage carrots, but carrots are harvested as early as late June to early July. These are then sold in the shops with their green leaves as "bunched carrots"

- some specialised farmers cover the carrots in late October with straw and harvest during wintertime too (southern Sweden)

- 84 300 metric tonnes produced carrots in Sweden in 1999

Herbicides (authorised for use in carrots in Sweden 2001)
Fenix - aclonifen
Basta - glufosinate
Sencor - metribuzin
Expand Plus - setoxidim (control of Elymus repens, [Agropyron repens])
Focus Ultra - cycloxidim (control of Elymus repens, [Agropyron repens])

Herbicides under registration: "Raft" from Aventis

Main programme for weed control

Conventional farming

- On sandy soils: aclonifen (1.5 l)+ glufosinate (2.5) just before emergence of crop.

- On sandy soils when the weeds have seed-leaves and the crop has emerged and begins to develop the first true-leaf: aclonifen (0.75 l) possibly small amount of metribuzin (0.025 l)

- On sandy soils with the crop having 1-2.5 true leaves: aclonifen (0.75 l) + metribuzin (0.075 l).

- On sandy soils with the crop having 3-4 true leaves: aclonifen (0.75 l) + metribuzin (0.075 l).

Organic farming

- possibly stale seedbed preparation

- seeding in single rows, 100 seeds per metre

- flame weeding before crop emergence, about 40 kg of LPG-gas per ha possibly in-row brush weeding when the crop has 2-3 true leaves

- repeated intra-row cultvations with hoe equipped with A-shares

- handweeding approx 100 hours/ha

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Switzerland (by Daniel T. Baumann)

Acreage	(Field production):	1300 ha (15% of total field vegetable area)
	(Glasshouse)	2.5 ha (0.32% of glasshouse vegetable area)
Herbicide treated area (estimate):		90%
Main weeds or key weeds:		Galinsoga spp., Amaranthus spp., Echinochloa crus-galli, Polygonum spp., Portulaca oleracea, Matricaria chamomilla, Senecio vulgaris, Poa annua

 

Relevant cultural practices:
Generally carrots are drilled on 1.5 m wide "flat beds" either 4 rows with 0.3 m row distance or 3 rows with 0.5 m row distance. Recently an increasing proportion of carrots is cultivated on ridges. Row distances varies between 0.5 and 0.75 m with either one or two rows or one band of carrots drilled per ridge (depending on harvesting technology).

Herbicides registered for carrot production:

Dosanex (80% Methoxuron): 2.4 kg a.i./ha pre-or post-emergence after 3-leaf stage; 3 x 0.4 kg a.i./ha + 0.5 l/ha adjuvant post-emergence low-dosage-system.

Linuron (50% Linuron): 1-1.5 kg a.i./ha pre- or post-emergence after 2-leaf stage; 3 x 0.125 kg a.i./ha + 0.5 l/ha adjuvant post- emergence low-dosage-system.

Molipan (28.5% Linuron/19% Monolinuron): 0.7-1.2 kg a.i./ha post-emergence after 3-leaf stage; 3 x 0.24 kg a.i./ha post-emergence low-dosage-system

Stomp SC (Pendimethalin 400 g/L)): 1.2-2 kg a.i./ha pre-emergence

Golaprex (Orbencarb 806 g L-1/Metribuzin 100 g L-1): 2.7-3.6 kg a.i./ha pre-emergence

Agil (Propaquizafop 100 g/L): 0.07-0.125 kg a.i./ha post-emergence

Focus Ultra (Cycloxydim 100 g/L): 02-0.6 kg a.i./ha post-emergence

Fusilade ME extra (Fluazifop-P-buthyl 125 g/L): 0.19-0.4 kg a.i./ha post-emergence

Gallant 535 (Haloxyfop-P-methyl 108 g/L): 0.16-0.32 kg a.i./ha post-emergence

Targa Super (Quizalofop-P-ethyl 50 g/L): 0.038-0.125 kg a.i./ha post-emergence.

Most common IWM strategy (ca. 90% of production area):

- Period threshold concept approach (weed-free period until week 6-7).

- Contact herbicides (Glufosinate) or flame weeding 1-2 days before emergence.

- Pre-emergence treatments with residual herbicides (only if high weed pressure is expected).

- Post-emergence treatments (Metoxuron, Linuron), generally applied as low-dosage-system.

- Repeated hoeing or rotary cultivation combined with ridging.

Common strategy for organic production (ca. 10% of production area):

- False seedbed technique

- Flaming 1 day before emergence (emergence prognosis test)

- Repeated hoeing or rotary cultivation combined with ridging or brush hoeing

- Hand weeding (supported by carriers)

Relevant references (weed control):

Baumann, D.T., 1994. Low dosage-systems with herbicides in carrots. Acta Horticulturae 372, 117-125.

Baumann, D.T. Slembrouck, I., 1994. Mechanical and integrated weed control systems in row crops. Acta Horticulturae 372: 245-252.

Current research:

- Development of liquid mulch systems for carrot cultivation.

- Development of direct drill ridge-cultivation system with frost resistant and sensitive mulch cover for carrot production.

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The Nederlands (by Piet Bleeker and Rommie van der Weide )

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Turkey (by F. Nezihi Uygur)

Yellow types carrots (probably anthocyanin-free mutants) were selected and cultured in Syria and Turkey in the ninth or 10th century; then spread to China in the late 13th century and to Europe in the 14th century (ANONYMUS, 2001). 

Carrot Cultivation in Turkey:
Total vegetable production is 26.572.262 tons/year in 1.314.000 ha of Turkey (ANONYMOUS, 1998). Carrot production is 235.000 tons according to 2000 year datas in Turkey (DIE, 2001). Middle Turkey especially Ankara is the main province for carrot production.
Recently adaptation projects (including different sowing date from August to November to get more yield during the whole season) for Cukurova Delta-South Turkey is still in progress. The results are very promising (DASGAN, 2001). Carrot production in these region will be strongly recommended to farmers by the scientists in the near future.
Informations were given below according to VURAL et al.(2000).

Soil Preparation and Sowing:  
Seed bed must be prepared very well to germinate of carrot seeds. Because carrots seeds are very small.
Soil must be free from some soil pests such as Agriotes spp., nematodes and weeds. Seeds sow by seeder and sowing deepth is 2.5-3 cm. 600-800 gram seeds for 1 da area. 5-12 cm on the rows, 25-40 cm inter-rows. Germination temperature must be more than 10 C.

Cultural Practices: It is necessary to be reduced of number of seedlings when the carrots are in the 2-3 true leaves stage.

Fertilization: Nitrogen and Potassium are very important for carrot. Potassium increase sugar rate in carrot. In the early stage organic fertilizer must be used. Inorganic fertilization should be done 2-3 weeks before sowing.
Irrigation: Regular irrigation is important for primer and sekonder root system of carrot.

Harvest and Storage: Maturation period in carrot depends on the variety. It takes 8-16 weeks. Harvest can be done by hand or machine. Storage temperature between 3 and 5 C.

Weed Species in Carrot in Turkey:

Common weeds were listed in Table 1.

 

Table 1. Common weeds in carrot fields in Turkey

Acroptilon repens Alhagi pseudalhagi Amaranthus lividus Amaranthus retroflexus Avena spp. Centaurea depressa Chenopodium album Chondrilla juncea Cirsium arvense Conringia orientalis Convolvulus arvensis Cynodon dactylon Echinochloa crus-galli Galium spp. Heliotropium spp. Isatis sp. Lactuca serriola Malva spp. Matricaria chamomilla Portulaca oleracea Reseda lutea Salsola kali Setaria viridis Sinapis arvensis Sonchus arvensis Solanum nigrum Tribulus terrestris Xanthium strumarium Xanthium spinosum

Weed Control:
Weeds are problem since the seeds of carrot germinate late. In this condition, weeds become more competitive.
There is not enough study specificially on weed control in carrot in Turkey. Couple studies were on to determine effective herbicides against major weed in carrot fields ( ERCIS & TASTAN, 1992; YANMAZ et all, 1992).
ERCIS and TASDAN (1992) established a plot in Ankara in 1990 according to randomized block design with three replications. They used Nantes Forte carrot variety. Main weeds were Amaranthus retroflexus, Portulaca oleracea, Echinochloa crus-galli and Setaria viridis in the experiment area. They applied Trifluralin (pre-sowing), Diflufenican, Prometryn and Linuron (pre-emergence), Fluazifob buthyl, Metribuzine, Prometryn, Linuron (post-emergence). They determined that there was more than 90% herbicide effectiveness against particular carrot weeds. They also concluded that the yield could be increase 600-900 times using correct weed management.

Cultural and Mechanical Control:

- Well prepared seed bed.

- Minimum one year decomposed manure

- Rotation

- Hoeing

 

Table 2. Registered Herbicides against grasses and broadleaf weeds in carrot fields in Turkey (ANONYMOUS, 1995).
Trade name	Formulation	Doses (Preparate)	Application Time
Trifluralin % 48	E.C.	200 ml/da	Pre-sowing
Linuron % 47.5	W.P.	150 g/da	Pre-emergence
Prometryn % 50	F.W.	200 g/da	Pre-emergence
Fluorochloridone	E.C.	250 ml/da	Pre-emergence
Linuron % 47.5	W.P.	150 g/da	Post-emergence
Prometryn % 50	F.W.	200 g/da	Post-emergence
Fluazifob-P-butyl % 12.5	E.C.	100 ml/da	Post-emergence

References:

ANONYMOUS, 1995. Tarim ve Koyisleri Bakanligi Koruma ve Kontrol Genel Mud. Zirai Mucadele Teknik Talimatlari. Cilt 1, Ankara 1995.

ANONYMOUS, 1998. Turkiye Istatistik Yilligi. T.C. Basbakanlik Devlet Istatistik Enstitusu. Yayin no: 2240, Ankara.

ANONYMOUS, 2001. www.uga.edu/vegetable/carrot.html

DASGAN, H.Y., 2001. Personel communication.

DIE, 2001. Devlet Istatistik Enstitusu 2001 yili verileri.

ERCIS, A., A. TASDAN, 1992. Orta Anadolu Bolgesi Havuc Ekim Alanlarinda Sorun Olan Yabanci Otlara Karsi Gesagard 500 FW Ilacinin Denenmesi. Zirai Muc. Aras. Yil., 1985-1986, 241.

YANMAZ, R., A. ERCIS, K. DEMIR, B. TASDAN, 1992. Havucta yabanci ot kontrolu ve bazi ilaclarin verim ve kaliteye etkisi. Turkiye I. Ulusal Bah. Bit. Kong. Bil., Cilt II: 161-164.

VURAL, H., D. ESIYOK, I. DUMAN, 2000. Kultur Bitkileri (Sebze Yetistirme). Ege Universitesi Ziraat Fakultesi Bahce Bitkileri Bolumu, Bornova Izmir. 440 pp.

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United Kingdom (by R.J. Froud-Williams)

In the United Kingdom, carrots are grown on two extremes of soil type, very light sands and high organic matter peats. Both soil types are encountered in East Anglia on the Breckland and Fens respectively, the major areas of production in Britain.
The area grown averages about 13,000 ha per annum, as was the situation in harvest year 2000 but was as high as 15,552 ha in 1991/92 harvest years compared with 11,018 ha in 1998/99. The crop produces approximately 500,000 tons per year, ranging from 495,000 - 625,000 tons per annum over the period 1991-1999. Provisional output for 2000 was 674,400 t. Yields per hectare ranging from 34.5-56.8 t/ha. Yields and quality of crop tend to be better for the sandy soils, which are intensively irrigated.

Carrots are generally grown on a de-stoned raised bed system 1.8-2.0 m between wheelings, with usually 4 rows per bed, but occasionally 3-5 rows, sown at seed rates of 1.25 - 2.5 million seeds /ha. at a variety of row spacings depending on type of crop and time of planting, but usually 35.0- 37.5 cm. row spacing. Carrots are sown from December to June, providing a harvestable crop for 9-10 months of the year. The introduction of spun polypropylene (fleece) has enabled the early sowing of crops, but has encouraged the incidence of Senecio vulgaris.

Typical weeds of mineral soils include Reseda lutea, Matricaria spp., Polygonum aviculare and Fumaria officinalis while on organic soils Chenopodium album, Polygonum maculosum and Stellaria media are prevalent.

In the U.K, carrots were the first vegetable crop in which effective chemical weed control was achieved with the introduction of mineral oils in the late 1940's. Although the majaority of the hectarage is treated with herbicides, those grown for early market are widely spaced to allow for inter-row cultivation. Whether grown organically or conventionally weed control is essential, for uncontrolled weeds can result in total yield loss. For organically grown carrots a single mechanical weeding four weeks after 50% crop emergence is optimal to prevent yield reduction (Bevan et al.,1993).

Commonly used herbicides include trifluralin (pre-plant incorporated), linuron pre-emergence (especially for C.album and Fallopia convolvolus) pentanochlor, prometryne post-emergence for annual broad-leaved weeds and CIPC + pentanochlor for Poa annua. Currently metoxuron is approved for use against Matricaria spp., but its future depends on EU review. If withdrawn, the occurrence of volunteer potatoes would present a major problem for growers. Both ioxynil and isoxaben have off-label approval, the latter with activity against groundsel, but with potential risk of crop damage. Perhaps the most intransigent weed of carrots on The Breckland is Reseda lutea for which pendimethalin is approved, but not entirely successfully, sometimes necessitating the use of metribuzin (off-label approval). A range of graminicides are registered for grass-weed control including cycloxydim, fluazifop-P-butyl, propaquizafop and quizalofop-P- ethyl.

Reference
Bevan J.R., Bond W. and Lennartson M.E,K.(1993). 4th Int. Conf. I.F.O.A.M, 327-332.

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