Seeding should be prevented by cutting, pulling or hoeing the plants before flowering. Prickly sow-thistle seeds have been found as a contaminant in clover, grass and cereal seeds, particularly in home saved cereal seed. The seeds have been recovered from irrigation water. Prickly sow-thistle seeds ingested by earthworms have been found intact in the worm casts. Viable seeds have also been found in cow manure. The seeds are eaten by birds and viable seeds may be found in their droppings. Under damp conditions the pappus of hairs collapses and dispersal is prevented. The plumed seeds are normally wind dispersed and seeds have been collected by aircraft at 2,000 ft. The half-life of seeds in cultivated soil is just 1 year while in dry storage it is 2-3 years. This is followed by flower bud formation and stem elongation. Spring emerging seedlings reach the rosette stage after 6 weeks. Seedling emergence occurs from March to November, with peaks in March-April and August to November, but odd seedlings can germinate at any time. Seeds on the soil surface germinate better than those buried at 30 mm deep. Light and stratification at low temperatures stimulate germination. Prickly sow-thistle can be found in fruit for 3 months of the year. Moisture stress also reduces the number of seeds formed. In a competitive cereal crop a plant may have just 500 seeds. Seed numbers per plant generally range from 21,500 to 25,000 but a large plant may have 60,000. The average number of seeds per flower head is 198, and a plant often has over 100 flower heads. Mature seeds (achenes) are formed 1 week after flowering. Prickly sow-thistle flowers from June to October. It is host to various aphids and acts as a reservoir to several important plant viruses including beet western yellows. Prickly sow-thistle has been used as a potherb since ancient times. It is generally less abundant than the smooth sow-thistle, S. In seedbank studies in arable fields in France, prickly sow-thistle was well represented in the seedbank and in the emerged vegetation.Ī number of ecotypes and varieties of prickly sow-thistle are described but environmental conditions also influence the appearance of the plant. Prickly sow-thistle seed was found in less than 1.5% of arable soils in a seedbank survey in Scotland in 1972-1978. In a study of seedbanks in some arable soils in the English midlands sampled in 1972-1973, prickly sow-thistle was recorded in 53% of the fields sampled in Oxfordshire and in Warwickshire. Prickly sow-thistle grows on most soils but prefers well drained slightly acid to alkaline soils, and has some tolerance of saline conditions. It is also found in gardens, on roadsides, waste places and other disturbed habitats. Prickly sow-thistle is a troublesome annual or overwintering weed common on arable land. Spiny annual sow-thistle, spiny-leaved sow-thistle, spiny milk-thistle, spiny sow-thistle Latin names
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |