WEEDS AND SEEDS INJURIOUS

New Zealand Journal of Agriculture, Volume 78, Issue 1, 15 January 1949, Page 52

WEEDS AND SEEDS INJURIOUS

ANY factor influencing the value of the wool clip is of major importance to New Zealand as a whole and weeds which produce seeds or burrs that devalue wool and sheepskins as industrial products are the concern of every farmer. In the following article R. G. Montgomery, Sheep and Wool Instructor, Department of Agriculture, Hastings, deals with several weeds common to various parts of the North Island and gives the generally-accepted common name and the botanical name of each species, with a short description of the seeds and the manner in which they affect the woollen industry. FARMERS should note the' name of each weed and use it when ref erring to the' particular seed or plant, as that would obviate much of the. confusion caused through common plants being known by two or more different names on adjoining farms. Stork's Bill Stork’s Bill. (Erodium) is also known as crow’s foot, sheep’s parsley, 12 o’clock, and corkscrew. Farmers often confuse the plant with wild parsnip or wild carrot and it' is sometimes misnamed black jack by wool buyers and brokers. Black jack (Stipa variabilis) is a totally different plant, with a longer though similarly-awned seed, which has a bad ' reputation in Australia and is known in some parts of Banks Peninsula and Marlborough. ’ The botanical name Erodium comes from the Greek “erodios,” a heron, no doubt because of a fancied resemblance between the head of the bird and the seed head of the plant. The.seed has a long awn which, as it matures or dries, will wind itself into a tight spiral, the awn turning with a circular motion. The awn is hygroscopic—the tightly-coiled shaft becomes damp it will immediately begin to unwind, and it is this ability to wind and unwind which gives this type of seed such a bad reputation in the woollen industry. - . , - ' There appears to be difference of opinion as to whether the Erodium species are annual or perennial, but most authorities consider them annuals or possibly biennials. Three species are recorded’ in New Zealand, Erodium moschatum, E. cicutarium, and E. malacoides, with some doubtful hybrids. The plant has a deep tap root, trailing

stems (which are short in some grazed pastures, but maybe 2ft. or more long where plants are protected or less palatable than the surrounding pasture), - feather-shaped leaves 4in. to 18in. long, and a small purplish flower. / Drought Resistance Though often regarded as. a weed, Erodium is often considered a valuable constituent in pastures on light or dry sandy soils, where it may afford feed after other plants have perished .in drought conditions. Because of its drought-resisting ability, Erodium is likely to become much more noticeable during seasons when drought con- ' ditions open up the sward. Knolls or crests under dry conditions, gateways where tramping has opened up the turf, or open flat pastures after a dry period are places where the entry of the weed may be first noted. Though ' it has been, present for many years, the fact that stork’s bill is at present conspicuous in many parts of Hawke’s Bay may be attributed to three consecutive dry seasons, and as the plant appears to have thrived and spread in many areas, even to suburban parks and private lawns, it should be closely watched before shearing time. In particular attention is necessary in relation to lambs’ wool, because last season wherever stork’s bill seed was present in fleeces there was a considerable reduction in prices paid for lambs’ wool. On some properties stork’s bill is used for fattening, but on others it appears to be less palatable to stock than the surrounding pasture and -is thus left to grow and seed unchecked. Seed Damage to Wool A heavy. loss in wool values is attributable, to the difficulties experienced by the woollen industry in removing Erodium seeds from the wool. The spiral awns work their way among the wool fibres and are stated to resist« ... all the usual means employed, other than carbonising, for the removal of vegetable matter. (Carbonising involves treatment of the wool with dilute sulphuric acid and subsequent baking and dusting out of the remaining charcoal). Consequently many prospective buyers do not bid for Erodium-inf ested, lines. Lambs’ wool is affected most by . the seed and where the specification of non-infested wool would be “average” to “good,” infested wool would be classified as “inferior” and as a result would be worth, on the past season’s market, at least 6d. a pound less, irrespective of the fact that these inferior grades are very much harder to dispose of and are the first lines to be affected by a falling market.

Damage to Pelts . Tho -.rainp nf r>Al+<? denends verv lately on toe condition oFtheir gram nn Which the wool side the side on which in grained Site will process many kinds ol fancy leathers such as glove leathers, etc., faulty-grained pelts have to be used for cheaper basils and linings. Erodium seed, with its hygroscopic , awn, often screws its way through the wool and the seed itself becomes embedded in .the grain of the pelt. Even after the elaborate chemical treatment for removal of the wool and subsequent liming, fleshing, bateing, and curing, a large proportion of seed remains embedded. This breaks the grain and thus ruins the pelt for any of the better grades of leather. On many lamb pelts there are hundreds of seed holes, and though no actual infection or isores might , have been apparent on the lambs, the retarding effect of irritation and discomfort to

growing animals must have been considerable, for though the seed does not completely penetrate the pelt, as is the case with barley grass, it penetrates the § rain and remains embedded be|ee E n the rain and flesh side 01 the SKin - Spread Must be Watched Spread Must be Watched Though the full extent of the trouble caused to the sheep and wool industry by Er odium and its seed may not be readily apparent to fat lamb producers, an inspection of affected lambs’ wool and damaged sliped pelts from lambs from Erodium-infested pastures would be instructive. The growth of Erodium no doubt has been assisted and the effect of the seed aggravated as a resuit of breaking of swards during a succession of dry seasons, but any spread of a weed of this nature must be watched closely. Though the full extent of the damaging effect of this seed to the woollen industry is. still a

matter of conjecture, wool containing this seed is graded “carbonising” and devalued accordingly. On much of the Maraekakaho and Tikokino ' country in Hawke’s Bay Erodium tends to take charge; it often dominates sowings of better grasses, particularly when the latter have not established well. Erodium then takes charge and ultimately fattens the stock. Whatever virtues Erodium may possess .must be weighed against its disadvantages and even . if the weed does fatten stock in dry periods, allowing it or encouraging it to dominate may prove a very costly business, as with its coiled, spiral awn Erodium seeds readily and is easy to pick up and transport. It would appear that on heavilyinfested Erodium areas the. best method of attacking the weed is by sowing of. suitable pasture mixtures and by building up the fertility so that an unbroken sward of increasing density is provided.

Barley Grass

Barley grass (Hordeum murinum) is a troublesome annual weed on many farms.- Its barbed seed head possesses remarkable penetrating ability which, irrespective of its natural advantages as far as its reproduction is concerned, can be \ a direct menace to stock and a continual worry to farmers. The seed has long, sharp awns which make it like > a barbed , spearhead and allow one-way movement only. The sharp projections on the . awns act as stops —ratchet fashion — any movement forces the seed forward. This injurious penetrating ability results in considerable damage to stock and a corresponding loss to farmers each year. \ z

Damage to Pelts and Stock

Barley grass seed punctures can result in severe septic wounds in stock and when sheep graze on infested country the barbed seed becomes attached to the wool and often travels inward, completely penetrating the skin. The seed is considered a menace in freezing works and fellmongeries, as it is responsible for 'considerable annual loss, (both in the returns from

skins and of material available for processing) , since many pelts are badly scarred, pock marked, or punctured by it, and any blemish or injury to the grain side of a pelt prevents its use for high-class leathers. \ ; The amount of damage done to pelts is seldom fully, appreciated by farmers and a visit to a freezing works when stock from ; barley grass-infested country are being killed will prove : illuminating. The damage to pelts is incidental to '■ continual irritation, which must check fattening stock. Eye, ear, mouth, and foot troubles must be guarded against when stock are in contact with barley grass, because if they pick up the seed from pasture or hay and it enters one of the parts mentioned,' it can cause a troublesome or serious septic sore. Seed.'penetrating the gum between the teeth can cause teeth to drop out. Dogs working on barley grass country are particularly susceptible to foot injury, because the seed may become embedded between the toes and work up into the foot or leg muscles. Barley grass,- which is fairly-widely distributed, thrives on broken turf, wherever animals camp, and in old, thin pastures. Apart from ploughing to eradicate barley grass it is advisable to cut the grass before the seed matures and .to heap it up and burn it to prevent seed from spreading. Barley grass must be heaped before burning, as it is necessary to develop considerable heat to destroy the seed. If the cut grass is burnt where it falls, the seed is often merely singed, which fails to prevent germination. A smaller species of barley grass (Hordeum marinum) is often found on coastal pastures, but because it is less conspicuous it should not be overlooked. ■ Barren Brome , Barren brome'. (Bromus sterilis') can be even more troublesome than barley grass, as the awns are often longer and harder and have serrated edges. The weed, which appears to be worthless, grows on roadsides, river-beds, camp sites, and sandy pastures. It is

an annua j which has a drooping seed head, leaves covered with long hairs, and a seed cluster that is purple at the base. , . ' ""?<•' Burr Clover „ Burr clover (Medicapo hispida) is P to^oo cons derable annual . manufacturers The hooked burrs of th clover become entangled in the , f ffrazine and ® n g sheen a\d wool otgraang and remove from the shorn 6 pteeeT°lt e i?Sot to seed which damages the wool, but the hooked and spiralled seed pod. This coiled pod unwinds during wool processing, and as it is fibrous it can pass through ■ the carding machines and thus mar the finished woollen product.. Wool, containing , burr clover seed must always be classed separately, It is better to leave a seedy fleece

unskirted than to skirt it and to inelude burry pieces with good, free pieces. Wools contaminated by burr clover usually require carbonising, a process which involves extra labour, added cost, and greater risk. Burr clover, the . leaf of which is trifoliate is about the same size , as that of white clover> but the flowers are y ellow and may be single or in clusters of U P to five. On much of the fattening land in the warmer districts burr clover, which is an annual, “J?” ““fe rowds out more valuable p slu e p a s. c_._44 o j R.. rr r'| rtuor ■3po< T ea Durr Clover Spotted burr clover (Medicago arabica) is sometimes called spotted medick. It is very like burr clover except that the leaflets have a large, black central spot. As with any other burry wool, fleeces infested with

Medicago arabica must be separated at classing, unless the - whole clip is affected. If many burrs are seen, it is logical to conclude that many more are embedded in the wool and the whole clip will usually be graded for burr. Under no circumstances must the grower risk any burr being found in supposedly wool. Piri pin Piri piri (Acaena sanguisorbae) , commonly called bidi-bidi, hutiwai, or utiwai, is a well-known native plant very common on bush-burn country. The seed ripens in a spiked ball, which in size may ' range from that of a shilling piece to a half-crown. The individual spikes have minute, barbed bristles which, combined with the easily-disintegrated ripe seed head, make it a real nuisance to woolly sheep and lambs. Many back-country farmers are forced to shear their flocks (including

lambs) early solely because piri piri seed can convert a complete fleece into a hard, solid mat of wool and seed. The fine, hooked awns create another problem for the woollen industry, as some may pass through the processing machinery in the woollen mills, producing defects in finished materials. Wools containing piri piri seed must always be classed separately, for though carding machines may take light seed, any heavily-infested wool must be carbonised, and is graded accordingly. Piri piri is usually unpalatable to stock and appears to withstand grazing by sheep, but where topdressing is done and sufficient cattle are carried the weed can be checked or eradicated. Piri piri spreads by prostrate, spreading stems which creep through pastures closely grazed or overgrazed by sheep. On topdressed and spelled country the growth of grass lifts the

runners off the ground and heavy stocking with cattle is then beneficial, particularly where efficient subdivision can be done. Shearing before burrs are ripe reduces the extent of wool contamination.

Bathurst Burr

Bathurst burr (X antilium spinosum) is a shrub-like plant from 9in. to sft. high, which favours waste areas about sheepyards, woolsheds, and river-beds, and neglected corners on good land. The under-side of the leaf and the stem are whitish, the stem being studded in groups of three at each joint—with needle-like spines often lin. -long. The seed, which grows on the stems at the base of the leaves, is a hard oval" burr thickly studded with hooked prickles. It is very easily picked up and becomes firmly embedded in the wool. , In the hardness of Bathurst burr seed lies the principal danger, because it may damage manufacturing machinery in the woollen mills.. Any wool containing the seed —usually occasional fleeces only—must be kept out when classing is being done, or the ; price for a whole clip may be affected.

Sheep's Burr

Sheep’s burr (Acaena ovina) , which was introduced from Australia,, has foliage similar to piri . piri, but the seeds are in small, round, hooked burrs along the stems, which are often 2ft. long. The stems have a reddishpurple tint.' The space between the hooked seed pods .diminishes toward the stem tips, where the burrs are clustered. Where sheep ' are running on an area heavily infested with sheep’s burr the whole of the wool clip may have to be classed as burry. It is more usual, however, for. only a few fleeces to be affected, but these must be kept separate in skirting or classing. v ' A «

Burdock

Burdock (Arctium lappa and A. minus) is a strong, shrub-like . plant sometimes found about river-beds, sheepyards, woolsheds, or places where

sheep cleanings- or dags have been dumped. The plant may be from 2 to 4ft. high and has a purple, thistle-like flower with a sheath of sharp, hooked spines. * It is the sheath, which may be so sharply hooked that it will attach itself to bare skin, that becomes en-tangled-in the wool.

Subterranean Clover

Subterranean clover (Trifolium subterraneum) is a very useful plant which has been the means of raising carrying capacity on many fertile, lowrainfall areas and on light soils of low natural fertility. The seed is contained in a hooked pod which can become embedded in the wool. The important point from the wool grower’s point of view is that'heavy contamination with subterranean clover seedthe plant often seeds during the busy shearing period cause wool to be classed as burred. Where a whole clip is affected not much can be done, but where seed shows in isolated fleeces only, they should be kept apart at skirting and classing, particularly, where some bellies are affected.

Thistles

Though not generally classed as seed or burr, Scotch, winged, star, Californian, nodding, and variegated thistles have a flower. head which can be a distinct nuisance to the . woollen manufacturer, as, if unnoticed at sorting, it will break up in the carding machine. •_ The fibrous-casing particles may strip down to show fibres in a finished cloth and the downy centre may become mixed with the wool where, though hard to detect in natural-coloured wool, it will become very obvious in dyed cloth, because the ’ vegetable matter does not take the dye as does wool. Heavy thistle contamination of fleece or piece wool may cause it to be graded - “carbonising” and for . that reason it is wise to

separate any affected fleeces at skirting time. Blackberry, Brier, Horehound, Gorse Blackberry, brier, horehound, and gorse particles should be removed from the wool in the woolshed at shearing time, or the fleece containing these particles should be kept separate. Fine particles of sticks, bark, or thorns which may pass through a carding machine can give endless trouble at woollen mills by causing threads to break in the early part of processing. The particles cause.obstructions when the thread is passed through the shuttle and considerable time and labour - are wasted while machines are held idle to . repair broken threads.,

Bracken, Fern, Manuka ' . Particles of bracken, fern, manuka, or other r leaves often become thickly embedded in fleeces ' from rougher country, back wool being particularly affected. These fleeces should also be graded - separately to prevent their affecting the value >of the free fleeces. Loss to Wool Growers Burrs, seeds, and vegetable matter cause serious trouble in the woollen industry and can affect growers’ returns materially, especially today when there is such a shortage of manufacturing machinery. Naturally, under these conditions, the manufacturer wants raw materials which will give the largest output with the least strain on equipment, and only wool free from vegetable impurity can give that result. To obtain free, wool the buyer is willing to pay a premium, with the result that faulty grades are neglected and prices fall accordingly.

Maximum Weights for Bales of Wool

A BALE of slipe, lamb, carbonised, scoured, or fleece wool, packed separately or with any other wool, must not exceed 4001 b. in weight; a bale of bellies, crutchings, locks, pieces, and other oddments, packed separately or'together, must not exceed 4501 b. That is the effect of the Board of Trade (Wool-packing) , Regulations, 1948, which came into operation on November 18. It is now an offence to pack for sale or transport, to consign, deliver, or transport, or to cause to. be 1 consigned, delivered, or transported a bale of wool which exceeds the maximum prescribed by more than 2| per cent., but wool packed before the regulations came into effect is exempted.