Distribution and seed production of Cirsium arvense (L.) Scop. in Victoria, Australia.

Amor, R. L.; Harris, R. V.

In 1971 the net area of <em>Cirsium arvense</em> in Victoria was 1300 ha in permanent pasture, 120 ha in cropping land and 40 ha in non-agricultural land. In ten farms in the most heavily infested parish (approximately 100 km²), <em>C. arvense</em> was present in 35% of the fields and occurred in some highly productive legume-based pastures. The most common control practice on these farms was pasture slashing. It was considered that the weed had been on the farms for 40-80 years. At a constant temperature of 20°C, but not at alternating temperatures, the germination percentage of seed was enhanced by pre-chilling. At constant temperatures the germination percentage was higher at 30°C than at lower temperatures. Alternating temperatures that included 30°C also increased the germination percentage, but it was depressed at 15°C/40°C. The germination percentage of seed from forty sites was 52%-97% and some seed was formed where male and female plants were separated by distances of up to 390 m. However, no seed was found in about a third of the parishes examined.

VICTORIA; AUSTRALIA; CANADA thistle; SEED distribution; SEED industry; CIRSIUM

Weed Research, 1974, Vol 14, Issue 5, p317

0043-1737

Academic Journal

10.1111/j.1365-3180.1974.tb01068.x