Fact sheet about Tagetes minuta

Distribution and habitat

It is an invasive weed on farms. It grows well in disturbed areas and cultivated beds, usually found in on farms. Originally from South America but is now an exotic, widespread weed in Africa, South Europe, South Asia and Australia. In Kenya it is found in Nairobi, Taita Hills, Voi-Nairobi road, Kaimosi, Masai Mara, Kiambu, Nyeri, Embu and in Machakos.

Flowering and fruiting habits

It is a strongly scented annual herb with stiff erect stems up to 2 m tall. Leaves stalked, opposite, light green, up to 15 cm long, pinnately dissected into 4-6 pairs of pinnae. Leaflets lanceolate, margins finely serrate. Oil glands under leaves and on stems and involucres bracts. Inflorescences terminal with several tube-like capitula of dull yellow florets. Fruits, black achenes, narrowly ellipsoid and hard seeds, 6-7 mm long.

Uses other than pesticidal

Medicinal- It is used to treat gastritis, indigestion and intestinal worms. Externally it is used to treat skin infections and haemorrhoids. The essential oil treats fungal infections like athlete’s foot and boosts the respiratory system. It has antimicrobial, antiphlogistic, antiseptic, antispasmodic, cytophylactic, sedative, emollient, fungicide and hypertensive properties.

Other- It is used in perfumery and as flavour in beverages and the food industry.

Propagation and cultivation

Seeds germinate readily when sown fresh, without treatment. Seeds are sprinkled directly on soil or covered with soil. Germination takes place within one week. Seedlings can also be transplanted to pots. It grows well in disturbed areas, in heavy clay soils or sandy soils.

Seed collection & Storage

In Kenya, the seeds can be harvested in February, May and October. The fruits are sieved to remove the husks. One pod has several seeds.

Seed behaviour is orthodox. Viability of air-dried seeds can be maintained for several years in hermetic storage.

Parts used

Whole plant

Live roots

Preparation

Grind dried plants to produce powder

Plant extract

Essential oil

Boil leaves to produce a decoction

Secretions from live roots

Uses

Added to stored beans and maize

As a fumigant

Application

Ingested by livestock

Target organisms

Maize and bean weevils

Against aphid Brevicoryne brassicae and red spider mites in vegetables

Against ticks

Against intestinal parasites in domestic livestock

Against nematodes, worms, insects, fungi and perennial weeds