Planteværn Online > Skadevoldere - Weed biology<br> <sub>Agro-region: Denmark</sub> - Scentless Mayweed SU-res

Crop Protection Online

24.4 2024

Weed biology
_{Agro-region: Denmark}

Scentless Mayweed SU-res

Can be mistaken for

Corn Chamomile, which has sparse hairs on true leaves.

Corn Marigold, which is blue/green and with a substantial layer of wax (greyish surface).

Mugwort, which has hairy true leaves.

Pineapple-weedwith maximum 2 incisions on the first 2 true leaves.

Scentless Mayweedthat is morphologically identical but not resistant to SU-herbicides

Scentless Mayweed ALS-resthat is morphologically identical but resistant to all ALS-herbicides

Resistance to herbicides

There have been significant populations of this weed in Denmark, which requires special considerations in the control. Read more here.

Characteristics

CotyledonsOval with entire leaf margins. Unstalked. Smooth surface. Length approx. 4-6 mm.

True leavesThe first true leaves have many deep incisions. Stalked. Smooth surface. Length approx. 10-12 mm. Later true leaves are pinnatisect.

Mature plantScentless Mayweed is a high plant (30-70 cm), which can become very vigorous, especially in open crops. The diameter of the flower is approx. 40 mm. Seed production: Up to approx. 34,000 seeds per plant.

SeedShaped like a slightly curved, truncated 3-4-sided cone. The surface has 3-4 longitudinal, light veins. Two types can be found: broad ray seeds and more slender disc seeds. Thousand grain weight approx. 0.35 g.

Biology

Propagation and dispersalOnly through seeds.

HabitSummer and winter annual.

Importance

The species is found very frequently in both autumn- and spring-sown crops throughout Denmark. The species is an injurious weed, which causes losses in all crops. In a large number of seed crops Scentless Mayweed is a troublesome weed because it is difficult to separate the seeds.

For treatment options, consult 'Herbicides Across'.
For more options, consult 'Main Menu'.

Taxonomy

Compositae.

Names in different languages

Danish :	Kamille, lugtløs SU-res
German :	Duftlose Kamille SU-res
English :	Scentless Mayweed SU-res
Latin :	Tripleurospermum inodorum SU-res
Norwegian :	Balderbrå SU-res
Swedish :	Baldersbrå SU-res

Seedling

Early stage

Flower head

Mature plant

Seeds

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Weed biology Agro-region: Denmark