A Benghal wandering Jew seedling.
Adult plant.

 

Underground seed and inflorescence.
Seed of Benghal wandering Jew.

 

Scientific name: Commelina benghalensis
Afrikaans names: Bengaalse wandelende Jood, Bengaalse-Commelina,wandelende Jood, blouselblommetjie
English name: Benghal wandering Jew, Benghal Commelina, Wandering Jew

Short description

Benghal wandering Jew is a multi-branched, rather erect annual soft herb. It has thin roots and white underground runners (rhizomes) that also produce flowers and seeds. Stems are round, bright green, ribbed and hairy (hirtous). Although it has broad leaves, they have the typical parallel venation of monocotyledonous plants.

Leaves are simple, alternately arranged, egg-shaped (ovoid). Flowers are axillary, small, ink-blue, nearly sessile and last for only a few hours.

It has the ability to produce both aerial and subterranean flowers with seed. Fruits are capsules with three locules and contain one semi-orbicular seed in the dorsal locule and two compressed seeds in each of the other two locules.

The aerial seed is small and the subterranean seed is rather big. They are grey to nearly black and the surface of the testa is rough. Reproduction occurs in various ways, namely by means of seeds, which occur above-ground (small), as well as underground (large), and also through cuttings.

Distribution

Widespread in southern Africa, but more common in summer rainfall regions. It is regarded as difficult to control.

Because of difficult and insufficient control, this weed is rapidly increasing – especially where reduced tillage or no-tilling is practised. When occurring in dense stands, it becomes a strong competitor.  Later in the season it forms a thick “matt-growth” between crop rows, especially when crops are physiologically matured making control difficult.

Control

Cultivation
Shallow hoeing with a harrow will only cut the plants in pieces and if the cuttings are not buried deeper than 50 mm, it will root and regrow. Cuttings will only die if they are buried deeper than 50 mm. Therefore shallow hoeing with a harrow will rather spread than control the weed.

Chemical
Chemical control is the best method of control for this weed. The small, subterranean seed emerges in shallow soil and pre-emergence herbicides usually gives the most effective control. The large subterranean seed can emerge as deep as 150 mm and pre-emergence herbicides gives precarious control. Therefore post-emergence herbicides gives better control of Benghal wandering Jew, while hormone type herbicides (2,4-D, dicamba and MCPA) are the most effective.

Where wandering Jew is a serious problem, the best results will be obtained by a split application of a suitable grass herbicide pre-emergence, followed by a post-emergence application of a suitable broadleaved herbicide. Wandering Jew seedlings should preferably not be sprayed around four leave stadium and no later than six leave stadium.

Several herbicides are registered for the control of wandering Jew in maize and wheat (Table 1 and Table 2). On most of the labels of the herbicides a note on the control of wandering Jew can be found and doses usually have to be increased for effective control.

TABLE 1: Herbicides registered on maize for the control of wandering jew.

Active ingredient Formula Time of application
acetochlor


700 g/litre

840 g/litre

900 g/litre

960 g/litre
Pre-emergence and early post-emergence of the crop


acetochlor/atrazine/simazine


160/165/165 g/litre

Pre-emergence, with planting or just after planting


acetochlor/atrazine/terbuthylazine125/187,5/87,5 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

Pre-emergence, with plant or within three days after planting. Early post-emergence, but not later than four leaf stage of the weed


acetochlor/EPTC

150/350 g/litrePre-emergence of weed and crop


alachlor384 g/litre

480 g/litre
Pre-emergence, with planting or just after planting



alachlor/atrazine336/144 g/litrePre-emergence, with planting or just after planting

atrazine

500 g/litre

900 g/kg
Pre-emergence, with planting or just after planting

atrazine/bendioxide
200/200 g/litre
Post-emergence, between two to six leaf stage of the weed
atrazine/cyanazine

167/333 g/litre

250/250 g/litre
Pre-emergence and early post-emergence of the crop
atrazine/mesotrione/s-metolachlor

208,5/26,8/208,5 g/litrePre-emergence of the crop and weed
atrazine/metazachlor/terbuthylazine

210/60/210 g/litrePre-emergence or within three days after plant. Post-emergence as follow-up application
atrazine/metolachlor

300/300 g/litrePre-emergence or within three days after planting

atrazine/metolachlor/terbuthylazine


174/252/174 g/litre

262,5/175/262,5 g/litre
Pre-emergence and early post-emergence, but only where grasses have not emerged yet and broadleaf weeds are not bigger than four leaf stage

atrazine/s-metolachlor


370/290 g/litre

Pre-emergence, within three days after planting

atrazine/sulcotrione

300/125 g/litre

Pre- or post-emergence application

atrazine/terbuthylazine

250/250 g/litre

270/270 g/litre

300/300 g/litre

450/450 g/kg
Pre-emergence or early post-emergence, before broadleaf weeds have reached four leaf stage

bendioxide

480 g/litre

Post-emergence, when weeds are actively growing

bromoxynil

225 g/litre

450 g/litre

Post-emergence, before weeds reach six leaf stage

bromoxynil/terbuthylazine

150/333 g/litre

Post-emergence

dicamba

480 g/litre

700 g/litre
Post-emergence, till crop is 30 cm tall. Can also be mixed with atrazine

dimethenamid-P

720 g/litre

Pre-emergence or within three days after planting

dicamba/topramezone

160/50 g/litre

Early post-emergence before six leaf stage, use in tank mix with atrazine or atrazine/terbuthylazine and Dash HC

glyphosate/mesotrione/s-metolachlor

250/25/250 g/litre

Post-emergence, only on glyphosate-tolerant cultivars

mesotrione

480 g/litre

Pre- or post-emergence. Only use in tank mix with atrazine, atrazine/ terbuthylazine or s-metolachlor

mesotrione/s-metolachlor

83,3/416,7 g/litre

Pre-emergence of weed and crop

metolachlor

800 g/litre

840 g/litre

915 g/litre

950 g/litre
Pre-emergence or within three days after planting

metribuzin

480 g/litre

Post-emergence, between four to six leaf stage of the weed, when weeds are actively growing

s-metolachlor

915 g/litre

960 g/litre
Pre-emergence or within three days after planting

s-metolachlor/terbuthylazine

312,5/187,5 g/litre

Early post-emergence, in tank mix with mesotrione

tembotrione

420 g/litre

Early post-emergence, use in tank mix with Atrazine 500 SC, ammonium sulphate and Ballista

terbuthylazine

600 g/kg

Pre- and early post-emergence, till four leaf stage

TABLE 2: Herbicides registered on wheat for the control of benghal wandering jew.

Active ingredient Formula Time of application
2,4-D




480 g/litre

500 g/litre

720 g/litre


Apply between growth stages seven to 13 of the crop




2,4-D/dicamba




240/80 g/litre



Apply between growth stages seven to 13 of the crop






bendioxide



480 g/litre



Apply to young, actively growing weeds




bromoxynil





225 g/litre

450 g/litre


Early post-emergence, before six leaf stage of the weed





dicamba



700 g/kg

Use only in tank mix with Enhancer (10 g tot 12 g) and Reaper (10 g) and a wetter (adjuvant)





MCPA400 g/litre

700 g/kg
Apply between growth stages seven to 13 of the crop

Therefore the specifications and doses for control of the wandering Jew have to be adhered to.

Always contact a reliable advisor before using any chemicals to ensure the correct dose on the label is adhered to.
Contact the writers at elbe.hugo@syngenta.com (Elbe Hugo) and, deweth@arc.agric.za (Hestia Nienaber).