Mustard Weed Found At Timaru

Press, Volume XCVII, Issue 28542, 22 March 1958, Page 9

Mustard Weed Found At Timaru

Several plants of Mediterranean mustard, a troublesome weed in cereal crops overseas, have been found in New Zealand. The plants were discovered on waste land at Timaru and it is believed they grew from seed accidentally introduced in Australian grain handled at the port. The plants were identified by the Botany Division of the Department of Scientific and Industrial Research. '

Mediterranean mustard is an erect, hairy annual, growing from 6in to 6ft high, with a long taproot and distinct turnip smell. The stems are erect, round in cross-section, branching, wavy, bristly-hairy below.

The basal leaves form a .rosette Ift to 2Jft in diameter, are stalked, with four to 12 lateral segments and a large terminal segment often more or less three lobed; the lateral segments decrease in size toward the base of the leaf. The stem leaves are few and much smaller than the rosette leaves. The heads are many flowered, lengthening in fruit. The flowers are pale yellow and small.

The seed pods or fruits are on stalks about Jin long, the pod IJin to 2|in long, containing 10 to 22 seeds. The pod has a long conical beak about a third the length of the pod proper, and carries one or two seeds near its base. The Seeds are small, globular, and pale purple-brown. The following methods of control have been used in Australia:—Pullihg and hoeing scattered plants; clean fallow; taking heavily infested land out of cropping and using it for grazing; refraining from sowing of crops until as late as possible to allow seedlings to germinate with the autumn rains. In Western Australia the amine salt of 2,4-D at 6oz acid equivalent per acre applied at one to two and a half gallons per acre by both aerial spraying and lapd spraying proved successful in controlling the weed.