Weeds

Thlaspi arvense L. - Field Pennycress.

Taxonomy.

Family Brassicaceae Burnett (Cruciferae Juss.), Genus Thlaspi L.

Biology type.

Spring annual weed, can overwinter.

Morphology and biology.

Plant is 10-60 cm in height, glabrous. Stem is simple or branched. Lower leaves are oval-oblong, petiolate, upper leaves are oblong-lanceolate, sessile, with cuneate base, more or less dentate along the edge. Inflorescence is raceme. Flowers are actinomorphic, consisting of four components, petals are white, sepals are green, deflected. Fruit is silicle, broadly-winged along the edge. Seeds are oval-reversed or oval, cherry-colored or brown. Plant flowers in June-August, bear fruits in July-September. Maximum productivity is up to 50,000 seeds. Seeds begin to ripen before harvest and, shattering, infest soil, part of them get into yield and infest crop seeds. The process of germination of unripe fresh seeds goes as quick as that of ripe ones. Seeds maintain their ability to germinate up to 37% passing through the digestive system of animals. Seed ability to germinate increases after over-wintering. Optimum temperature of seed germination is 20-24°C, minimum: 2-4°C, maximum: 34-36°C. Seeds germinate best of all from depth of up to 1 cm, their viability is maintained up to 10 years.

Geographical range.

It occurs across all agricultural regions of the Former USSR. General distribution: All Europe, West Asia (up to Himalayas), Mongolia, China, Japan, Korea, North America and North Africa.

Ecology.

Anthropochore, autochore. It occurs in all types of soil, preferring lower and moistened places. This weed is characterized by high viability; pulled-up plants, which are left in the field, are able to take root. Spring form of Thlaspi arvense mainly infests spring crops. Its winter form infests winter crops and is able to over-winter as a rosette. This plant can over-winter also in the flowering stage.

Economic value.

This weed is resistant soil disturbance by field cultivation. It infests winter crops. Thlaspi arvense often occurs and is abundant among grain and tilled crops, in fallows, pastures across forest and forest-steppe zones, in steppe- and semi-desert zones it occurs more rarely. It is also found in irrigated fields in oases. This weed is widely distributed in ruderal places - in abandoned lands, waste places, near houses, along railways and earth roads. Seeds contain 20-33% oil, which is suitable for industrial purposes. Control measures: shallow plowing in autumn and spring for eradication of plant rosettes. Thorough fallow treatment, pre-sowing cultivation, early autumn plowing. Fertilization of fields by well-decomposed manure.

Reference citations:

Agaev M.G., ed. 1988. Main agricultural weeds in crops of the Leningrad Region. In: Catalogue of VIR world collection. Leningrad: VIR. N. 468: 50-52. (In Russian)
Keller B.A., ed. 1934. Weed plants of the USSR. Leningrad: AN SSSR. V. 3: 36-38. (In Russian)
Komarov, V.L & N.A. Bush, eds. 1939. Flora of the USSR. Moscow-Leningrad: AN SSSR. V. 8: 581. (In Russian)
Korsmo E. 1933. Weed plants of modern farming. Moscow-Leningrad: Publishing House of Kolchoz & Sovchoz Literature. 122-124 pp. (In Russian)
Nikitin V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. 218 p. (In Russian)
Ulyanova T.N. 1998. Weed plants in flora of Russia and other CIS countries. St. Petersburg: VIR. 236 p. (In Russian)
Zotova A.P. 1971. Weed plants and their control. Leningrad: Lenizdat. 86, 88 p. (In Russian)

© S.Yu. Larina.

 

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