By John Ippolito, Regional Crops Specialist, Ministry of Agriculture, Regional Services, Kindersley
Scentless chamomile is a noxious weed in Saskatchewan that can be identified by its finely divided leaves and distinctive flower.
The flower is 2 to 4 cm in diameter and has white outer ray florets and a central disk of yellow florets that give it a daisy like appearance. The plant can be a summer annual, winter annual or a short-lived perennial.
Scentless chamomile normally occurs in wetter habitats such as the black and grey soil zones. However with a couple of wetter growing seasons in the dark brown soil zone we are now seeing more of it in areas such as west-central Saskatchewan as well. Preferred habitats for this weed are moist areas that have experienced some level of soil disturbance and have little competition from other plants. As a result it is commonly found on road sides, utility right of ways, shelterbelts and around fringes of wetlands as the water recedes.
Scentless chamomile is of particular concern because of its differing growth habit and ability to produce seeds. A single plant could produce as many as 500,000 seeds that are only about 2 mm long. As a result infestations can happen quickly in areas with a lack of competitive plants.
There are a number of control measures that landowners can implement to control establishment and spread of this weed. These include:
– Reduce or eliminate spread of seed through other materials such as grain and forages
– Shallow tillage of infested areas under hot, dry conditions
– Mowing or swathing – should be done prior to flowering and may need to be repeated during the growing season.
Equipment should be cleaned prior to leaving the infested area
– Use of competitive crops such as perennial grasses, barley and winter wheat
– Hand weeding
For more information on the biology and control of scentless chamomile refer to the factsheet – Scentless Chamomile on the saskatchewan.ca website.
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