Chamomile, Scentless (Matricaria perforata Merat.)

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Table of Contents

1. History
2. Life Cycle
3. Distinguishing Characteristics
4. Control in Corn
5. Control in Soybeans
6. Control in Winter Wheat

History

A very common species throughout Ontario, and becoming more problematic in field crops on heavier ground, particularly where no-till cropping systems are in place.

Life Cycle

Biennial or short-lived Perennial. Reproduces by seed.

Distinguishing Characteristics

In the early stages this weed is often confused with pineappleweed, stinking mayweed or yarrow as all of these weeds have very finely divided leaves. However, scentless chamomile will be the only species that doesn't exude an odour when the leaf tissue is crushed. When scentless chamomile is mature, it can be confused with stinking mayweed, however stinking mayweed is shorter in stature and exudes an unpleasant odour.

Scentless Chamomile Pictures
Each thumbnail image links to a larger image

Herbicide Control in Field Corn

Glyphosate and tank-mixes with glyphosate provided the best control of scentless chamomile. None of the other corn herbicides tested provided adequate control of scentless chamomile. It should be noted that the ratings in Table 1 are based on scentless chamomile that was quite large (10 to 40 cm in height). In this trial there wre also seedling populations of scentless chamomile. Control of scentless chamomile was greatly improved when herbicides were applied to the seedling stage of this weed (2-5 cm.). However, none of the "non-glyphosate" treatments provided control of scentless chamomile. DISTINCT provided the best activity of seedling scentless chamomile at 78% control.

* Indicates that glyphosate can only be applied post-emergent to Roundup Ready corn hybrids.

Source:
Dr. Clarence Swanton, University of Guelph.

Number of Trials:
Table 1 based on a summary of 1 field trial .

Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide to Weed Control.

Weed Stage:
Secntless chamomile ranged from 10 to 40 cm in height at the time of application.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.

Herbicide Control in Soybeans

General Control in Soybean

Unfortunately, few products offer any control of scentless chamomile in soybean. Glyphosate has offered the most consistent control of scentless chamomile and should provide good control if applied both pre-plant and post-emergent to "Roundup Ready" soybeans (Table 1). For conventional soybeans, the majority of scentless chamomile seedlings will have emerged early in the spring and therefore a pre-plant glyphosate application should provide good control throughout the season.

Source:
Dr. Clarence Swanton, University of Guelph.

Number of Trials:
Table 1 is based on a summary of 1 field trial.

Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide to Weed Control.

Weed Stage:
Scentless chamomile was betweem 10 to 40 cm in height at the time of application.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.

Herbicide Control in Winter Wheat

Initially Dr. Swanton and Kevin Chandler investigated control of scentless chamomile with fall herbicide applications as a majoirty of scentless chamomile will emerge in the fall. However, trial observations showed that a considerable amount of scentless chamomile also emerged in the spring and therefore fall applications did not offer effective control throughout the season.

Successful control of scentless chamomile (Table 1) was achieved with spring applications of REFINE EXTRA, BUCTRIL M, BADGE or MEXTROL and the tank-mix of REFINE EXTRA + BUCTRIL M. Grower and retail agronomist experience has told us that control of scentless chamomile has been difficult to achieve even with those herbicides mentioned in Table 1. However, it is felt by Dr. Swanton and Kevin Chandler that the key to successful control is to apply the herbicide of choice when scentless chamomile is small (i.e. 2-6 leaf stage), which for this particular trial coincided with the first week in May.

*DAA = Days after application

Source:
Dr. Clarence Swanton, University of Guelph.

Number of Trials:
Table 1 based on a summary of 1 field trial in winter wheat.

Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide to Weed Control.

Weed Stage:
Scentless chamomile was at the 2 to 4 leaf stage (5 cm in height) at the time of application.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.