Sencorex Flow

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Active materials

For use only as an agricultural herbicide with contact and residual action for use in early and maincrop potatoes.
A suspension concentrate formulation containing 600 g/L metribuzin.

Sencorex Flow is a selective herbicide, containing metribuzin 600 g/L, with contact and residual properties, acting by both leaf and root uptake for the control of annual weeds in early and maincrop potatoes. Sencorex Flow may be applied pre-emergence on the listed early and maincrop potato varieties.
Post-emergence application may be made to the listed maincrop varieties. The contact action of Sencorex Flow becomes apparent 7-14 days following application to germinating weeds.

DO NOT treat the textural group of soils known as ‘Sands’.

 Black-bindweed Black-grass Bugloss Charlock Chickweed, Common Cleavers Clovers Dead-nettle, Henbit Dead-nettle, Red Fat-hen Forget-me-not, Field Fumitory, Common Groundsel Hemp-nettle, Common Hemp-nettle, Large flowered Knotgrass Marigold, Corn Mayweeds Meadow-grass, Annual, Mercury, Annual Nettle, Annual Nightshade, Black Oilseed rape volunteers Orache, Common Pansy, Field Penny-cress, Field Persicaria, Pale Pimpernel, Scarlet Poppy, Common Redshank Runch Rye-grass, Perennial Scutch (Couch), Common Shepherd’s-purse Sorrel, Sheep’s Sow-thistle, Smooth Speedwells Spurrey, Corn Wild oat.
Rate: 1.15L/ha
Critical comments: Maximum total dose (L product/ha/crop) 1.15; 0.55 (see other specific restrictions). Latest time of application: Pre-crop emergence; Before the shoots of potatoes reach 15 cm in length. Other specific restriction: The maximum total dose for 1st earlies is 1.15 L product/ha applied pre-crop emergence only.

When herbicides with the same mode of action are used repeatedly over several years in the same field, selection of resistant biotypes can take place. These can propagate and may become dominating. A weed species is considered to be resistant to a herbicide if it survives a correctly-applied treatment at the recommended dose. A strategy for preventing and managing such resistance should be adopted.
This should include integrating herbicides with a programme of cultural control measures. Guidelines have been produced by the Weed Resistance Action Group and copies are available from Teagasc, your distributor, crop adviser or product manufacturer.

Common Couch grass (Scutch)
Where Sencorex Flow has been applied pre-emergence a recommended graminicide used according to manufacturer’s instructions may be applied post-emergence provided 3 weeks has elapsed between applications and that the scutch is growing actively.
Other Perennial Grass Weeds
In situations where potatoes follow grass an autumn herbicide treatment or cultivations should be used to kill out the sward. Shoots appearing from any surviving turves may be controlled post-planting using an approved contact herbicide according to manufacturer’s instructions.
Subsequent seedling weed control can then be obtained using a post-emergence application of Sencorex Flow.
Wild oat
Sencorex Flow will give some control of germinating seedlings up to the 2 leaf stage but not seedlings germinating from considerable depth. Where infestation is severe it is suggested that the first flush can be controlled by cultivations, or with an approved contact herbicide applied according to the manufacturer’s instructions, followed by Sencorex Flow post-emergence (on maincrops* only) for further control of later germinating wild oats and for seedling weed control.
Factors Affecting Activity of Sencorex Flow
Cultivations should produce a soil tilth that requires no further improvement after planting. Cultivation after spraying will encourage weed germination and reduce the residual activity of Sencorex Flow.
For good control of weeds germinating after application the soil should be moist at the time of treatment and the ridges well rounded with few clods. Dry soil conditions may reduce the activity of Sencorex Flow and weed control may be less satisfactory.
Where the soil is cloddy it is advisable to increase the volume of water.
On mineral soils with a high organic matter content and on peaty or organic soils, the residual activity of Sencorex Flow may be reduced.
On stony or gravelly soils there is a risk of crop damage especially if heavy rain fails soon after application.

Maincrop Potatoes
Varieties Suitable for Treatment
Post-emergence applications may be made to the listed maincrop varieties*, but not after the most advanced shoot’s have reached 15 cm (6 in) in length.
Application should not be made beyond this stage. Occasionally when Sencorex Flow is applied after crop emergence, slight yellowing may occur (particularly in Kerr’s Pink) which is normally out-grown without affecting yield; this occurs more frequently when application is made under hot, sunny conditions. For best results Sencorex Flow should be applied when the majority of weeds are at the cotyledon to 1 true leaf stage.

Early Potatoes (First and Second earlies)
Sencorex Flow should be applied pre-emergence only on the listed first and second early varieties*. Potato shoots emerged at the time of spraying will be yellowed and may be scorched. Before applying Sencorex Flow to early potatoes it is important to refer to the section on ‘Succeeding Crops’.

A “top-up” dose of 0.55 L/ha may be applied early post-emergence to named varieties on the soil types listed above providing the most advanced shoots have not reached 15 cm in length.
Do not exceed a maximum total dose of 1.7 L/ha.

Sencorex Flow should be applied in not less than 200 litres of water per hectare.
Ensure that the boom is set at the correct height and that an even coverage to both sides of the potato ridge is obtained. When applying Sencorex Flow post- emergence it is particularly important to achieve good penetration so that weeds shaded by the crop are covered with spray mist. For optimum results avoid spraying in windy conditions.
Before application to early potatoes it is important to refer to the section ‘Following crops’.
Take care to avoid drift onto neighbouring plants and crops, particularly sensitive crops which include sugar beet, lettuce and brassicas.
Temporary Plastic Mulches
Application of
Sencorex Flow to well prepared clod-free ridges should be made in at least 200 litres of water per hectare.
Weed control by Sencorex Flow is dependent upon adequate soil moisture being present to allow sufficient uptake of the product by seedling weeds. If the soil moisture status is low at application weed control will be impaired. The soil should, therefore, be thoroughly wetted by irrigation or rainfall before the plastic mulch is applied.
On mineral soils with high organic matter content or peaty or organic soils the residual activity of Sencorex Flow may be reduced, resulting in inadequate weed control.

Before drilling or planting any succeeding crop the soil MUST be mouldboard ploughed to a depth of at least 15 cm (6”) taking care to ensure that the furrow slice is inverted. Ploughing should be carried out as soon as possible (preferably within 3-4 weeks) after lifting the potato crop, but certainly no later than the end of December.
In the Same Year
Provided at least 16 weeks have elapsed after the application of the recommended rate of Sencorex Flow, the following crops, may be grown:
ryegrass, cereals and winter beans.
In the Following Year
In the Spring of the year following Sencorex Flow usage, any crop apart from lettuce or radish may be grown. Lettuce and radish crops are particularly sensitive to metribuzin and should not be grown in the year after Sencorex Flow usage.

Half-fill the spray tank with clean water. Commence agitation. Steadily add the recommended quantity of Sencorex Flow to the spray tank (pre-mixing is not necessary). Complete filling and maintain agitation of the suspension before and during spraying until the tank is empty. Spray immediately after mixing.

Tank mixing
When tank mixing it is important that the appropriate manufacturer’s literature recommendations are followed and care taken to ensure applications are made within the recommendations for both products.

Sencorex Flow may be applied as a tank-mix with a range of products. Contact Bayer CropScience for compatibility information on specific tank-mixes. Full manufacturer’s instructions must be followed for each tank-mix component.


Registered for culturesRate
Potatoes1.15 l