Stinking mayweed

Scientific name: Anthemis cotula
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Stinking mayweed has a very strong, unpleasant smell when its leaves are crushed
  •  Plants are usually 25-30 cm tall and the flower heads 2-3 cm in diameter
  • Large daisy-like flowers have a yellow centre with white rays and leaves are divided into fine narrow segments
  • Small bristles on the raised central portion of the flower head remain after the seeds have fallen
  • Can be fairly erect in flower or well branched and bushy.

Origin

  • Native habitat ranges from southern Europe to western Siberia where it grows in both natural and agricultural environments
  • Has been introduced to the USA, Canada, Argentina, and Australia as well as to New Zealand.

Life cycle

  • Stinking mayweed is usually a summer-growing annual but seeds germinate at any time of the year when adequate moisture is available
  • Plants usually die after flowering and setting seed. Where flowering is prevented by grazing or cutting, stinking mayweed may survive through winter
  • Seedlings are weak, slow-growing and cannot survive in competitive pasture
  • Stinking mayweed often grows in pugged and disturbed areas, in particular holding pens and stock yards, and it is also common in newly sown grass especially near such areas.

Benefits

  • Decoctions from flowers and leaves have been used as an insecticide
  • Extracts from stinking mayweed are reputed to have an antibacterial effect and show activity against gram-positive and gram-negative bacteria.

Occurrence

  • Stinking mayweed is common in open pastures, waste areas, farmyards and roadsides throughout the North Island and northern South Island
  • Can be a significant weed in pasture, especially in the Waikato and Bay of Plenty, and also in cereal crops in the South Island.
  • Can cause taint in some arable crops

Impact on pasture

  • Highly unpalatable to all stock
  • Cattle avoid stinking mayweed and sheep will eat it only under intense grazing pressure

Grazing management

  • Grazing management can provide a measure of control and maintaining a vigorous and dense pasture sward can help prevent invasion of stinking mayweed
  • Rotational sheep grazing has been more successful in checking/eliminating stinking mayweed than a set stocking regime.

Chemical control

  • Stinking mayweed is fairly tolerant of phenoxy herbicides like MCPA, MCPB, 2,4-D or 2-4DB
  • The herbicide bentazone has provided good control of stinking mayweed, particularly of seedlings, with only temporary suppression of pasture growth (adding a wetting agent is recommended, especially for more mature plants)
  • The weed is susceptible to dicamba and herbicide mixtures containing this chemical give reasonable selective control in cereal crops, but will damage clovers
  • Lucerne can be sprayed with paraquat when dormant in winter for effective control
  • Herbicide products containing bromoxynil also provide good control in cereal crops
  • Stinking mayweed is susceptible to many residual herbicides used in field and horticultural crops.

ALWAYS READ PRODUCT LABELS BEFORE APPLYING

Active ingredient When to apply Residual effect Grass damage Clover damage
2,4-D amine Jun – Aug Slight No Slight
bentazone Jun – Aug Slight No No
bentazone/MCPB Jun – Aug Slight No Very slight
bromoxynil/ioxynil Jun – Aug None No Severe
dicamba Jun – Aug Severe No Severe
mecoprop/diclhorprop/MCPA Jun – Aug Yes No Severe

Consult your farm consultant, industry rep or the New Zealand Agrichemical Manual for more information about chemical control.

  • Popay I, Champion P, James T 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.
  • Young S 2013. New Zealand Novachem agrichemical manual. Agrimedia Ltd., Christchurch, New Zealand. 767 p.