Weeds and weed management in tomato

Details from single countries

Croatia France Israel Italy Morocco Poland Portugal Slovenia Portugal Spain Switzerland

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Croatia (by Teo Sanseovic)

Acreage: about 5'800 ha

Authorised herbicides
trifluralin, diphenamid, napropamide, pendimethalin, metribuzin, fluazifop-p-butyl, propaquizafop, sethoxydim.

Weeds
Main weeds : Abutilon theophrasti, Ambrosia artemisiifolia, Chenopodium album, Solanum nigrum, Datura stramonium, Amaranthus spp.
Species are becoming an increasing problem: A. theophrasti, A. artemisiifolia and D. stramonium

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France (by Robert Giovinazzo)

Acreage: about 5'000 ha

Weeds
The most important weeds
Annual grasses: Alopecurus myosuroides, Lolium multiflorum, Poa annua, Digitaria sanguinalis, Echinochloa crus-gallis, Setaria viridis.
Perennial grasses: Cynodon dactylon, Sorghum halepense.
Broad-leaved weeds: Papaveraceae (Fumaria officinalis, Papaver rhoeas), Brassicaceae (Raphanus raphanistrum, Rapistrum rugosum, Sinapis arvensis, Capsella bursa-pastoris, Diplotaxis erucoides), Scrophulariaceae (Veronica spp., Kickxia elatine), Asteraceae (Matricaria recutita, Senecio vulgaris, Sonchus oleraceus), Lamium amplexicaule, Mercurialis annua, Amaranthus retroflexus, Chenopodium album, Solanum nigrum, Datura stramonium.

Key weed: Solanum nigrum.

Species are becoming an increasing problem: Ambrosia artemisiifolia, Cirsium arvense and triazine-resistant Amaranthus hybridus

Authorised herbicides
metribuzin, pendimethalin, flurochloridone, sethoxydim, dichlofop-methyl, fluazifop-p-butyl, cycloxydim, quizalofop-ethyl.
Rimsulfuron is still under registration.

Integrated Weed Management
Early soil preparation plus harrowing or a pre-planting application of glyphosate, glyphosate trimesium, glufosinate-ammonium or diquat, diquat+paraquat could allow to control early-emerging weeds, including first emergence fluxes of S. nigrum (Branthôme, 1994).
In transplanted tomato, a pre-transplanting application of flurochloridone, pendimethalin, mixed with a low dose of metribuzin (125 to 175 g a.i. ha-), can be considered as the base of a weed management programme. Post-transplanting treatments allow to control weeds escaped pre-planting applications. Rimsulfuron could be applied at 10-25 g ha^-1 in one or more applications depending on weeds.
In direct seeded-tomato, a pre-sowing application of metribuzin (350 g ha^-1) should be followed by complementary applications of a mixture of rimsulfuron (20-25 g ha^-1) and metribuzin (125-175 g ha^-1) to control S. nigrum, particularly.

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Israel (by Yeshaiahu Kleifeld)

Acreage and management
There are about 3000 ha of tomatoes for processing and some 1000 ha fresh and this includes the greenhouses, for salad and for seed production, for the local seed companies.
The greenhouses were treated with methyl bromide, metham-sodium or formaldehyde for soilborn diseases and weed control is obtained.
The open field tomatoes acreage is totally treated with herbicides, 50 to 60% were treated with more than one herbicide.
Most of the acreage is transplanted with "cell grown transplants". This includes the open tomato fields for procession and open fields and greenhouses with tomato for salad (fresh). In most cases tomato is transplanted on raised beds and seedbed is prepared with a power driven rotovator. Crop establishment is achieved by sprinkler irrigation and then changes to drip irrigation.

Weeds
The most important weeds (*key problem, **= obstacle):
Amaranthus retroflexus**
Amaranthus blitoides*
Amaranthus palmeri
Amaranthus cruentus
Amaranthus graecizans
Solanum nigrum*
Portulaca oleracea
Cyperus rotundus**
Convolvulus arvensis*
Sorghum halepense
Solanum elaeagnifolium
Orobanche aegyptiaca**
Orobanche ramosa
Orobanche cernua
Cuscuta campestis

New and recently spread weeds:
Triazine resistant biotypes of Amaranthus blitoides
Orobanche aegyptiaca
Euphorbia heterophylla
Euphorbia maculata
Poygonum arenastrum

Critical period for competition
3-4 weeks, just after planting.
Removal of S. nigrum and A. retroflexus is very important at the end of the growth season to enable mechanical harvesting

Chemical weed control

Pre-planting treatments
Trifluralin (1.0-1.5 kg a.i. ha^-1) mechanically incorporated to 10 cm deep prevents: Amaranthus spp., Portulaca, Chenopodium and annual summer grasses during growth season. It suppresses Convolvulus, Sorghum halepense. Not controlled: Solanum nigrum, Cyperus rotundus. Low soil temperatures may halt tomato root system in trifluralin treated fields and inhibit plant growth.
Oxyfluorfen (0.36-0.48 kg a.i. ha^-1) sprayed on beds and activated by rain or sprinkler irrigation, 4 weeks to 4 days prior planting. It controls most annual weeds including S. nigrum until drip irrigation stimulates germination of new weeds. Sensitive weeds starts to emerge from soil slits. Heavy rains soon after planting or heavy sprinkler irrigation may splash soil+herbicid on lower tomato foliage and cause leaf burn.
Oxadiargyl (0.6-0.8 kg a.i. ha^-1) applied like oxyfluorfen, but safer for tomato and with a longer residual effect in preventing Amaranthus spp. and Solanum nigrum.

Post-planting treatments
Metribuzin (0.25-0.35 kg a.i. ha^-1) applied to already established stand (from 10 days after transplanting). It controls seedlings and prevents emergence of broadleaves except Solanum nigrum and triazine-R Amaranthus spp. Weak on grasses. Sprinkler irrigation after application is needed for effective weed control. For contact effective action we recommend to apply sprinkler irrigation after 24 hours. Crop selectivity is low at cloudy periods. Therefore treatment is delayed or lower rates were applied on cloudy days.
Rimsulfuron (0.0125-0.025 kg a.i. ha^-1) applied in post-emergence to broad-leaved weeds at seedling stage (about 3-4 leaves), grasses and Cyperus rotundus. This treatment fits very much drip irrigated fields where no sprinkler irrigation is used. It does not control Solanum nigrum and the higher rate is needed for Amaranthus blitoides control. For Cyperus rotundus and Sorghum halepense control a split application of 0.025 kg a.i. ha^-1 is applied and another 0.0125-0.0025 kg a.i. ha^-1 is applied following three weeks.
Trifluralin (1.0-1.5 kg a.i. ha^-1) sprayed on tomato transplants, following a mechanical incorporation between the rows and on bed shoulders with a "band" power driven incorporator to 8-10 cm deep. The treatment goal is to prevent Convolvulus arvensis infestation as well as emergence of many broadleaved and grass weeds. This treatment is done before putting the drip irrigation system.

Some selective grass killers (sethoxydim, quizaloofop-ethyl, fluazifop-butyl, clethodim and cycloxydim) are recommended in Israel for use in post-planting.

The most common Integrated Weed Management programme
a - Oxyfluorfen pre-planting + Rimsulfuron post-planting.
b - Trifluralin pre-planting incorporated + Rimsulfuron post-planting.
In case of Cyperus rotundus infestation: a or b with two treatments of Rimsulfuron post.
Hand weeding for Solanum nigrum and Amaranthus retroflexus control is used in organic farming.

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Italy (by Francesco Tei)

Acreage: 110'000 ha (processing tomato: 70'000 ha)
Production: 5.2 Mt (processing tomato 4.0 Mt)
Direct sowing: mid March - mid-April
Transplanting: April - May (South); mid April - Mid June (North Italy)

Weeds
Sown crops. During the first part of growth cycle the most important and frequent species are Avena spp, Alopecurus myosuroides, Lolium multiflorum, Polygonum aviculare, Fallopia convolvulus, Cruciferae e Compositae later on Echinochloa crus-galli, Setaria spp., Digitaria sanguinalis, Chenopodium album, Amaranthus retroflexus, Solanum nigrum, Portulaca oleracea, Polygonum persicaria e Polygonum lapathifolium.
Transplanted crops: Echinochloa crus-galli, Setaria spp., Digitaria sanguinalis, Chenopodium album, Amaranthus retroflexus, Solanum nigrum, Portulaca oleracea, Polygonum persicaria e Polygonum lapathifolium

Key weed: Solanum nigrum (italian common name: erba morella).

New and recently spread weeds: Abutilon theophrasti, Convolvulus arvensis, Calystegia sepium, Xanthium spp., Cyperus spp., Orobanche ramosa.

References: Viggiani et al., 1998; Montemurro & Tei, 1998.

Authorised herbicides on tomato in Italy

Integrated Weed Management programmes in Italy

Orobanche ramosa can be controlled by hoeing before weed seed development.

References: Montemurro & Sarli, 1994; ; Rapparini & Rubboli, 1994; Onofri et al., 1995; Montemurro & Tei, 1998.

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Morocco (by Si Bennasseur Rzozi)

Acreage: plastic tunnels 3'600 ha ; open field processing tomato : 9'000 ha

Relevant cultural practices
Under plastic tunnels : transplanting; plant density : 20'000 plants/ha; hoeing : 3 to 4 times.
Processing tomato: transplanting; plant density 20'000 plants/ha; hoeing: 1 to 2 times

Treated surface: plastic tunnels : 0 % ; open field processing tomato : 5 to 80% before plantation depending on rainfall.

Weeds
The most important weeds : Solanum nigrum, Chenopodium album, Chenopodium murale, Amaranthus retroflexus, Setaria spp, Echinochloa crus galli, Sonchus oleraceus,, Sonchus asper, Orobanche ramosa, Datura stramonium, Urtica urens, Convolvulus arvensis, Portulaca oleracea, Cichorium endivia, Ranunculus sardous, Cynodon dactylon, Anagallis foemina. Malva parviflora, Diplotaxis catholica, Emex spinosa, Daucus carota.

Key weeds or key problems : mainly annuals and some perennials

New weeds or new species : Convolvulus arvensis, Datura stramonium, Malva parviflora, Cynodon dactylon, Orobanche spp.

Critical period of competition: 1 to 1.5 months after transplantation.

Authorized herbicides: metribuzin, pendimethalin

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Poland (by Adam Dobrzanski)

Acreage: about 23'000 ha; treated area (estimate) : at least 30%

Weeds
Main weeds: Echinochloa crus -galli, Galinsoga parviflora, Chenopodium album , Solanum nigrum , Polygonum persicaria , Fallopia convolvulus, Amaranthus retroflexus, Thlaspi arvense , Capsella bursa-pastoris, Sinapis arvensis, Raphanus raphanistrum, Stellaria media, Matricaria spp., Anthemis spp.,Urtica urens, Viola arvensis, Senecio vulgaris.
Key weed : Solanum nigrum, Echinochloa crus-galli ,Chenopodium album, Galinsoga parviflora, Polygonum spp.
New and recently spread weeds: Galinsoga parviflora

Weed Management programmes

The most widespread weed mangement programme is:
pre-planting : trifluralin (Treflan 480EC or Triflurox 250EC) or metribuzin (Sencor 70WG at 0.25-0.35 kg ha^-1)
post-planting: metribuzin (Sencor 70WG at 0.25-0.35 kg ha^-1 7-10 days after transplanting)
inter-row mechanical cultivation is also widely applied.

Reference: Anyszka & Palczynski, 1997; Dobrzanski & Palczynski, 1998; Palczynski et al., 1997.

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Portugal (by Fatima Rocha)

Greenhouse estimated acreage: 1'200 ha
Open air estimated acreage: 17'000 ha; treated area (estimate): 100%
Relevat cultural practices
Nursery: January/February/March
Planting: March/April
Harvest: July-August-September
Distance between rows: 1.20 - 1.60 m

Key weeds: Solanum nigrum, Cyperus esculentus, Datura stramonium, Chenopodium album

New weeds: Orobanche crenata

Critical period of competition: first 3 weeks after planting

References: Rocha, Fátima, Calha, I. Graça, C (1998). Registered Herbicides in Portugal for Horticulture. DGPC. 80pp.

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Slovenia (by Andrej Simoncic)

Key weeds: Convolvulus arvensis, Cirsium arvense, Rumex crispus and Solanum nigrum.

Integrated Weed Management programme in tomato in Slovenia

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Spain (by Carlos Zaragoza)

Acreage: about 56'800 ha (treated: 70-75%)
Direct-seeded crops: 10-30% upon regions. Transplanted crops: 70-90%.

Weeds

New weeds: Datura stramonium, Abutilon teophrasti, Xanthium strumarium, Salsola kali.

Authorised herbicides for tomatoes in Spain

(-): before weed emergence. (+): after weed emergence.
(R): recommended but not registered.

Pre-sowing or Pre-planting with soil incorporation into the soil

• metham - Na/K 1000 kg a.i. ha^-1. Against Solanum nigrum. Row applied 15 days before planting, 7 days before sowing. Incorporate immediately into the soil after the application.

Pre-planting with incorporation into the soil

• butraline 1,92-2,4 kg a.i. ha^-1 (-) Incorporate immediately into the soil after the application.
• ethalfluraline 0,825-0,99 kg a.i. ha^-1 (-) Possible incorporation by irrigation.
• trifluraline 0,588-1,176 kg a.i. ha^-1 (-) Incorporate immediately into the soil after the application.
• napropamide 1,53-2,025 kg a.i. ha^-1 (-) Incorporate into the soil after within 48 hours from the application.
• dinitramine 0,48 kg a.i. ha^-1 (-) Do not use on direct seeded crop.

Pre-sowing

• metribuzin 0,10-0,35 kg a.i. ha^-1 + napropamide 0,9-1,35 kg a.i. ha^-1 (-) Just after seeding. Possible incorporation into the soil by irrigation.

Pre-planting

• pendimethalin 0.5-0.8 kg a.i. ha^-1 (-) Some action against Solanum.
• metribuzin 0,35-0,52 kg a.i. ha^-1 (-) If incorporated into the soil can delay crop growth.

Post-emergence

• metribuzin 0,07 (2 leaves stage) -0,14 (4 leaves) kg a.i. ha^-1 (+).
• rimsulfuron 0,0125-0,015 kg a.i. ha^-1 (2 leaves or more) (+) Add a surfactant.
• metribuzin 0,07 + rimsulfuron 0,0125 kg a.i. ha^-1 (2 leaves or more) (+) (R).

Post-planting

• metribuzin up to 0,525 kg a.i. ha^-1 (+) Apply 15 days after planting.
• prometrine 0,75-1 kg a.i. ha^-1 (+) Do not spray on the crop.
• rimsulfuron 0,0125-0,015 kg a.i. ha^-1 (+) One week after transplant. Possible mixture with metribuzin.

Post-emergence & post-planting grass killers

• alloxydim 0,75-0,94 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage
• clethodim 0,096-0,192 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage. Add a surfactant.
• fluazifop-butyl 0,156-0,25 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage. Add a surfactant.
• propaquizafop 0,100-0,150 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage. Add a surfactant.
• quizalofop 0,125-0,175 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage. Add a surfactant.
• sethoxydim 0,250-0,500 kg a.i. ha^-1 (+) After "2-4 leaves" crop stage. Add a surfactant.

Integrated Weed Management Programme
Very different criteria are used in different regions.
In some regions chemical control is disrecommended and as a consequence manual and mechanical practices are preferred. Under plastic-houses and on very light soils herbicides are not allowed (except gliphosate and sulphosate against perennials).
In other situations glyphosate, sulphosate and glufosinate against perennial weeds at very low rates are allowed. Metribuzin is frequently used in pre- and post-planting application. In post -planting metribuzin is allowed and often used in mixture with rimsulfuron.
The Spanish Weed Science Society is working for recommending technical criteria and good field practices in co-operation with the Plant Protection Services and chemical firms.

The most widespread alternative methods are: crop rotation (long and diversified with cereals, Liliaceae, legumes, cole crops), mechanical precision tillage (with recommendations based on good practice), hand weeding (small fields, low weed densities), plastic mulching (bands of black/grey PE); soil solarization is used under plastic-houses, but mainly for disease and nematodes control.
Other systems as thermal weed control are used in a very small scale.

In direct seeding crops the critical period of competition is very long: we need to control weeds from emergence until flowering time. In a clean field a good persistent pre-emergence treatment is enough, complementing with some precision tillings that can earth up the plans. In other situations 3 treatments must be enough for direct seeding (one in pre-sowing or pre-emergence and two in post-emergence). For mechanical harvesting a pretty clean field is necessary. Transplant tomatoes are more competitive but during flowering time they must be clean anyway.

References: Zaragoza et al., 1994.

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Switzerland (by Daniel Baumann)

Acreage (1997): Field production: 54 ha (0.66% of total field vegetable area); glasshouse: 189 ha (24% of glasshouse vegetable area).
Herbicide treated area (estimate): < 5%
Main part of tomato production is in glasshouses or cold plastic tunnels. Normally dead or living mulch systems, such as papers, plastics, straw, raygrass and clovers are used.

Main weeds or key weeds:
Echinochloa crus-galli, Lolium spp., Polygonum spp. Poa annua, Stellaria media

Authorised herbicides (1998)
Metribuzin, propaquizafop, cycloxydim, fenoxaprop-ethyl, fluazifop-P-butyl, haloxyfop-methyl, quizalofop-P-ethyl

Contacts
Main production area in canton of Vallais: Station fédérale de recherches Centre d'arboriculture et d'horticulture des Fougères CH-1964 Conthey. Tél. + 41 27 345 35 11 - Fax + 41 27 346 30 17
http://www.admin.ch/sar/rac/rachomee.html

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