Control of weeds in maize and wheat – Part 8: Goose grass

    2000
    Goose grass seedling.
    Tufted goose grass.

     

    Culm and seed.
    Adult plant with green culms.

     

    Scientific name: Eleusine corocana
    Afrikaans name: Jongosgras, osgras
    English name: Goose grass, rapoko grass

    Short description

    Goose grass is an annual tufted grass, growing up to 60 cm high. The grass has a strong and well developed root system. A characteristic of this weed is its powerful initial root development, which makes it so well adapted to the climate in southern Africa. Culms are often branched and kneed at the base and hairless. Leaves are up to 50 cm long and 1 cm wide, hairless and distinctively folded. Inflorescence is vivid light green and consists of two to ten one-sided spikes, arranged finger-shaped (dactylose) or half finger-shaped. Spikelets usually cross over each other and are also characteristically flat. Seeds (caryopses) are black, oval-shaped, up to 2 mm long and 1 mm wide. The surface is sharply ridged along the sides, across the whole seed.

    Distribution

    Goose grass is the most common grass weed of cultivated fields in South Africa. Because of the extended and vigorous root system, it is one of the most severe competitors with dryland summer crops. Most of the grass weed species’ seedlings look very much alike and it is sometimes difficult to distinguish between finger grass (Digitaria spp.), herringbone grass (Urochloa spp.), buffalo grass (Panicum spp.) and goose grass.

    Control

    Cultivation
    Goose grass can be controlled by means of shallow cultivation in the seedling stage. Shallow cultivation will bring fresh seed to the surface and cause them to germinate, which will require more cultivation (hoeing). However, goose grass will continue to germinate during the summer season and hoeing is not an efficient way of controlling it.

    Chemically
    The most efficient method of controlling grass weeds is by means of herbicides. Goose grass is one of the most susceptive grass species with regards to pre- and post-emergence herbicides. Grass herbicides give the most effective control and where heavy infestations occur, control should be as complete and timeous as possible.

    Various herbicides are registered for the control of goose grass in maize and wheat (Table 1 and Table 2). Strictly follow the specific instructions and dosages on each product label.

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

    Active ingredient Formula Time of application
    acetochlor700 g/litre

    750 g/litre

    768 g/litre

    840 g/litre

    900 g/litre

    960 g/litre
    Pre-emergence or early post-(crop)emergence

    Early post-emergence of the crop, use as tank mixture with atrazine and/or terbuthylazine

    Pre-emergence

    Pre-emergence or early post-emergence, within three days after planting

    Early post-emergence, use as tank mixture with atrazine and/or terbuthylazine

    Read label instructions
    acetochlor/atrazine/simazine

    160/165/165 g/litre

    Apply at or immediately after planting on a well-prepared seedbed

    acetochlor/atrazine/
    terbuthylazine
    125/187,5/87,5 g/litre

    150/225/225 g/litre

    178,6/160,7/160,7 g/litre

    250/225/225 g/litre

    350/175/175 g/litre
    Apply at or immediately after planting on a well-prepared seedbed

    Apply within three days after planting, but before crop and weed emergence

    Pre-emergence

    Pre-emergence or early post-emergence, Apply at, or immediately after planting on a well-prepared seedbed

    Pre-emergence or early post-emergence
    acetochlor/EPTC

    150/350 g/litre

    Pre-emergence

    alachlor384 g/litre

    480 g/litre
    At planting or immediately after, within two days after planting

    At planting or immediately after, within two days after planting
    alachlor/atrazine

    336/144 g/litre

    Pre-emergence on a well-prepared seedbed within two days after planting
    atrazine/mesotrione/
    s-metolachlor

    208,5/26,8/208,5 g/litre

    Pre-emergence

    atrazine/metazachlor/terbuthylazine

    210/30/210 g/litre

    Pre-emergence, within three days after planting

    Post-emergence as follow-up application
    atrazine/metolachlor


    300/300 g/litre
    Pre-emergence, within three days of seedbed preparation and planting
    atrazine/metolachlor/terbuthylazine

    174/252/174 g/litre

    262,5/175/262,5 g/litre
    Pre-emergence or early post-emergence

    Pre-emergence or early post-emergence
    atrazine/s-metolachlor

    370/290 g/litrePre-emergence, apply at/or immediately after planting on a well-prepared seedbed
    dimethenamid-P

    720 g/litrePre-emergence, apply within three days of planting

    dicamba/topramezone

    160/50 g/litreEarly post-emergence, before six leaf stage, use in tank mix with atrazine or atrazine/terbuthylazine and Dash HC
    EPTC720 g/litre

    Pre-plant, incorporate into soil, read the label

    flumetsulam

    800 g/kg

    Pre-emergence, use only in tank mix with metolachlor or S-metolachlor
    flumetsulam/s-metolachlor

    20/630 g/litre

    At planting on a well-prepared seedbed within three days after planting
    glyphosate/mesotrione/
    s-metolachlor

    250/25/250 g/litre

    Post-emergence, only on glyphosate resistant cultivars

    mesotrione/s-metolachlor

    83,3/416,7 g/litre

    Pre-emergence

    metolachlor800 g/litre

    840 g/litre

    915 g/litre

    960 g/litre
    Pre-emergence on a well-prepared seedbed, within three days after planting

    Pre-emergence, on a well-prepared seedbed, within three days after planting

    Pre-emergence, apply on well-prepared seedbed, within three days after planting

    Pre-emergence, apply on well-prepared seedbed, within three days after planting
    metribuzin

    480 g/litre

    Post-emergence, apply on actively growing weeds after they have emerged to the four to six leaf stage
    nicosulfuron

    40 g/litre

    240 g/litre
    Post-emergence, when crop is in two to six leaf stage

    topramezone226 g/litre

    Early post-emergence. Read label instructions

    s-metolachlor

    915 g/litre

    960 g/litre
    Pre-emergence on a well-prepared seedbed, within three days after planting

    Pre-emergence, read label instructions
    s-metolachlor/terbuthylazine

    102,8/497,2 g/litre

    312,5/187,5 g/litre
    Pre-emergence, on a well-prepared seedbed

    Early post-emergence, only to be used in a tank mix with Callisto

    TABLE 2: Herbicides registered for the control of goose grass in wheat.

    Active ingredient Formula Time of application
    trifluralin

    480 g/litre

    Pre-plant, dosage depends on weed species

    Always contact a reliable chemical advisor before applying any chemicals to ensure the correct dosage and specifications are adhered to.

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