Controlling common chickweed (Stellaria media) in strawberries

Characteristics:

Common chickweed is a winter annual. Winter annuals germinate in the late summer or fall, overwinter as small plants, then put on growth during the cool months of the spring. Most winter annuals cannot withstand hot weather, and will set seed and die in June or July. Common chickweed generally follows this pattern, but will sometimes also be seen to germinate through the spring and early summer, and plants can occasionally survive the summer in shaded areas.

Winter annuals are a particular problem for strawberry growers. In other crops, spring and/or fall tillage would disrupt the life cycle of this weed. In strawberries, the lack of tillage at these times and winter protection with mulch allows these weeds to survive and thrive. Renovation does not affect these weeds, as they have generally produced seeds by July.

Both common and mouse-ear chickweed are in the Caryophyllaceae, or 'pink' family. Well-known plants in this family include garden flowers such as carnations, Dianthus and Maltese cross. Other weeds in this family include mouse-ear chickweed and white cockle.

Common chickweed is edible, and leaves can be added to salads.

Figure 1. Common chickweed in May (weedinfo.ca)

Figure 1. Common chickweed in May (weedinfo.ca)

Figure 2. Mouse-earred chickweed (note hairiness) (weedinfo.ca)

Figure 2. Mouse-earred chickweed (note hairiness) (weedinfo.ca)

Figure 3. A 4-leaf common chickweed plant with oblong cotyledons (weedinfo.ca)

Figure 3. A 4-leaf common chickweed plant with oblong cotyledons (weedinfo.ca)

Figure 4. A young mouse-eared chickweed seedling (weedinfo.ca)

Figure 4. A young mouse-eared chickweed seedling (weedinfo.ca)

Importance:

Because common chickweed is low growing and shallow rooted, its ability to compete with strawberries is limited. It can, however, make harvest difficult and pick-your-own operations unattractive. If chickweed is left uncontrolled for many years, populations can build up to the point where yields are impacted. When common chickweed is present in great numbers, lower leaves of strawberry plants can be shaded. In addition, heavy infestations of this weed could block air flow around strawberry plants, increasing the likelihood of fungal disease problems.

Table 1 - Examples of herbicides that are labeled to control chickweed
Strawberries Potatoes Corn Soybean Wheat
2,4-D (high rate) Eptam Aatrex 480 Optill Refine SG
Betamix (US Label only) Chateau (Western Canada Only) Callisto + Aatrex 480 Pursuit, Phantom Refine M
Chateau (US Label only) Dual II Magnum Converge XT Prowl H20 Trophy
Devrinol Lorox Marksman Sencor  
Dacthal 75 W Sencor   Valtera  
Dual II Magnum        
Sinbar        
Treflan, Rival, Bonanza        

Management:

Chemical:

From Table 1 it appears that there are several herbicides that are registered in strawberries that will control chickweed. However, most if not all are restricted to when you can apply the herbicide during the crop growth stage. 2,4-D is not very effective on this weed. Labeled rates of Sinbar applied at mulching over emerged chickweed are generally ineffective. Effective control can be achieved with an application of Devrinol in late August. Since Devrinol does not control emerged weeds, it is important to make the application before emergence. While Dacthal can also control this weed from seed, residual control is too short to make this application cost effective. Dual II Magnum and Treflan should only be applied prior to planting strawberries; whereas, Chateau should only be applied to dormant plants. Betamix can only be applied to new June plantings, for a limited amount of time which may or may not coincide with chickweed emergence.

Non-chemical:

Cultivation between rows and a thorough hoeing in the late fall can be used to destroy overwintering seedlings. Control by hand is possible in the spring. This should be done as early in the season as possible, before plants begin to spread. Plants are not killed unless roots are destroyed. Crop rotation may be one of the most effective ways of preventing the build-up of chickweed. The conditions so favourable to chickweed in strawberries are not present in most other crops. Rotating out of strawberries every few years for several years at a time may be useful in keeping common chickweed and other strawberry weeds in check.

Bottom Line:

Use a combination of approaches for the most effective control of this weed.


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca