PASTURE PESTS

Wanganui Chronicle, Volume 74, Issue 114, 16 May 1931, Page 8 (Supplement)

PASTURE PESTS

RAVAGES OF GRASS-GRUB MEASURES FOR CONTROL MANURING AND HARROWING Prominent among many little things sent to try the patience and resource of the man on the land is the grass-grub, that silent but relentless worker, states K.P., in the N.Z. Herald. Already this season the grass-grub has taken toll oJ I a good many acres of grass-land in the Auckland Province and it would be as well to take stock of the position right away so that timely measures may be taken ot arrest the progress of the pest. The grub as found jn the soil at the present; lime, is at the most distinctive stage of its many sided career. First, of all the egg, from which the grub is hatched, is laid in the grass about the month of October; a ±ow weeks later the grub emerges and commences to find its food in the roots of grasses and clovers. The grub stage is long drawn out as, according to Frcain, it may exist as a grub from one to five years. From the grub to the pupa is the next stage; the pupa state being one of transition from the little ugly grub stage to that, of a fully-winged flying moth, which lays its eggs in the grass again and so commences a new cycle. Control Measures Control measures arc difficult as the grub is an underground worker and its presence is suspected only after a good deal of damage has been done. Consolidation of the land by means of heavy rolling or the concentration of stock on grub-eaten areas is recommende.l. Feeding out hay on grub-eacen patches brings about consolidation through the continued tramping of stock and at the same time re-seeding occurs from the seeds falling from the hay. {Something can also be done to check the trouble by spreading over the area an insecticide of one sort er another, while the free use of the discs to keep the patch, or patches, well stirred up and th« grubs exposed is probably the most effective way of checking the spread and preparing the way for a re-seeding of eaten-out areas, it. is said that there is scarcely an ace of grass land ir the country that does not contain grass-grub, but the grub is not able to make its presence felt in a vigorous, healthy sward. Effect of Harrowing. Pastures cut for hay too late in the season and then caught by a dry spell are likely to suffer damage. In the first place the food growth and absence of stock make this a likely place for the eggs to he laid, and in the second, the weakened aftermath is unable to resist attack. Regular and frequent harrowing of grass-land at the right time of the year should go a long way toward keeping the grub in check. Harrowing every I week or two in the early part of the season must disturb the eggs that are deposited, and result in a lower percentage being hatched out. Then, in the case of the hay or ensilage pad docks, if these crops arc cut early, rhe aftermath can get away past the stage where the grub gets the upper band. If harrowing had no other effect than to spread the manure ami keep the pastures clean for grazing it would be wed worth while, but there arc good reasons to believe that it has a more direct effect than that, and that the grass harrows are an excellent weapon of defence against the grub. Fertilisers Important. Probably the most efficient weapons of all, however, are fertilisers. Pastures kept up to a high standard jf quality and vigour as a result of using quickly available phosphates, potash land lime, will resist almost any insect attack. It is just; as necessary for pis turc plants to feed to live as it is for I grubs to feed to live, out their normal life cycle. If the plant is starved for the right kind of food then it is an easy matter for the grub to wage a successful war, but if the plant be ■well developed and liberally fed it is practically immune from attack. If one would be free from the ravages of a grass-grub invasion he mus’ start operations early and not wait; until the enemy is actually visible. Any rough, pastures should be cleaned up im mediately, top-dressed with a suitable fertiliser mixture and then be kep: right by regular harrowing. Even now it is not. too early to make a s*art, as autumn is probably the test rime of all for the application of fertilisers. Whe> the pastures are correJlv stalled off for the season and when this start is followe<l up by good pasture management the grub will make no headway. Fertilisers are the weapons with which to tight this pest, with gri-s harrows co operating all along the. lino.