Control of weeds in maize and wheat – Part 6: Herringbone grass

    1259
    Seedling
    Wavy leaves.

     

    U. panicoides and U. Mosambicensis.
    Adult plant.

     

    Scientific name: Urochloa panicoides
    Afrikaans name: Beesgras
    English name: Herringbone grass, Garden urochloa

    Description

    An annual tufted grass that can grow up to 90 cm high in favourable conditions. Culms are often decumbent with roots at the lower nodes, spreads outwards from the centre. Leaf sheaths are loosened from the culm, finely striped, hairy (hirtous) with small knobs at the base of the hairs, the ligule is a deep, ciliate edge. Leaves are light green and characteristically wavy (undulate), even as a seedling. Inflorescence consists of 2 to 7 spikes, each up to 6 cm long. Spikelets are in two regular rows, alternately arranged on the anthoclinium, hairless (glabrous), with the lower glumes one third of the length of the spikelet. Seeds (caryopses) are straw-coloured, ovally flattened, with fine ridges across one side, with a short, blunt apex.

    Urochloa mosambicensis (Bushveld herringbone grass) also occurs commonly and the difference between species can be seen in the florescence.

    Distribution: 

    Herringbone grass can be seen as one of the four “land grasses” due to their wide distribution and common occurrence in most crop species. It seems to prefer clayey soils, but can be a severe competitor on any soil type if the infestation levels is high enough. The grass is distributed through seed and germinate pre-dominantly in early spring.

    Control

    Cultivation
    Timely shallow cultivation can be done in early spring, since seed are shallow germinators and can be one of the first grasses to germinate.

    Chemically
    Most pre- and post-emergence grass herbicides can be used to successfully control herringbone grass. When the grass is controlled post-emergence, the applications must be applied as early as possible between the two- to four leaf stages. As soon as the herringbone grass starts to form tufts, control can be less effective.

    TABLE 1: Herbicides registered for the control of herringbone grass in maize

    Active ingredient Formula Time of application
    acetochlor700 gram/litre

    750 gram/litre

    840 gram/litre

    900 gram/litre

    960 gram/litre
    Pre-emergence or early post-emergence of the crop
    acetochlor/atrazine/simazine160/165/165 gram/litrePre-emergence or early post-emergence of the crop
    acetochlor/atrazine/terbuthylazine

    125/187,5/87,5 gram/litre

    150/225/225 gram/litre

    178,6/160,7/160,7 gram/litre

    250/225/225 gram/litre

    350/175/175 gram/litre
    Pre-emergence, with plant, or within days after planting Early post-emergence, not later than four leaf stage of the weed
    acetochlor/EPTC150/350 gram/litrePre-emergence of crop and weed
    alachlor384 gram/litre

    480 gram/litre
    Pre-emergence, with or just after planting
    alachlor/atrazine


    336/144 gram/litre
    Pre-emergence, with or just after planting
    atrazine/cyanazine

    167/333 gram/litre

    250/250 gram/litre
    Pre-emergence or early post-emergence
    atrazine/mesotrione/s-metolachlor208,5/26,8/208,5 gram/litrePre-emergence of weed and crop
    atrazine/metolachlor300/300 gram/litrePre-emergence, within three days after planting
    atrazine/s-metolachlor370/290 gram/litrePre-emergence, within three days after planting
    atrazine/sulcotrione300/125 gram/litrePre- or post-emergence application
    atrazine/terbutryn250/250 gram/litrePre-emergence, with plant or just after planting
    dicamba/topramezone160/50 gram/litreEarly post-emergence, before six leaf stage, use in tank mixture with atrazine or atrazine/terbuthylazine
    EPTC720 gram/litrePre-plant, incorporated into soil, consult product label
    flumetsulam200 gram/litre

    800 gram/kg
    Pre-emergence, use in tank mixture with metolachlor or s-metolachlor
    flumetsulam/s-metolachlor

    20/630 gram/litre

    With plant, or within three days after planting
    glyphosate/mesotrione/s-metolachlor

    250/25/250 gram/litrePost-emergence, only on glyphosate tolerant cultivars
    mesotrione480 gram/litrePre- or post-emergence. Use only in tank mixtures with atrazine, atrazine/terbuthylazine, s-metolachlor
    mesotrione/s-metolachlor83,3/416,7 gram/litrePre-emergence of weed and crop
    metolachlor800 gram/litre

    840 gram/litre

    915 gram/litre

    950 gram/litre
    Pre-emergence, within three days after planting
    metribuzin480 gram/litrePost-emergence when weeds are actively growing, four to six leaf stage
    nicosulfuron240 gram/litre

    40 gram/litre
    Post-emergence, when crop is in two to six leaf stage
    s-metolachlor915 gram/litre

    960 gram/litre
    Pre-emergence, within three days after planting
    s-metolachlor/terbuthylazine312,5/187,5 gram/litreEarly post-emergence, in tank mixture with mesotrione
    topramezone336 gram/litreEarly post-emergence, before six leaf stage, use in tank mixture with atrazine or atrazine/terbuthylazine

    TABLE 2: Herbicides registered for use on wheat for the control of herringbone grass.

    Active ingredient Formula Time of application
    trifluralin*

    480 gram/litre

    Use only in planted fields, dosage depends on weed species

    * Please note: Always check on the herbicide label that the specific herbicide is registered for use on the named weed species. Only certain tradenames are registered for the control of herringbone grass.
    Only registered herbicides may be used.

    Contact the writers at elbe.hugo@syngenta.com (Elbe Hugo) and deweth@arc.agric.za (Hestia Nienaber).