“WARBLE” FLY GRUB

Sun (Auckland), Volume IV, Issue 986, 31 May 1930, Page 5

“WARBLE” FLY GRUB

REASSURING STATEMENT ISSUED NEW ZEALAND IS SAFE Special to THE SUN WELLINGTON, Today. Alarm has been felt in country districts at the reported presence of “warbles” in New Zealand, and a reassuring statement is issued by the Department of Agriculture. The “warble” fiy grub is well known in Britain, Europe and in Canada, but has never become domiciled in South Africa, Australia or New Zealand, and the official statement is that the Dominion is safe from the pest, as experience has proved that conditions here are not suitable. In the disease, small, rounded swellings appear immediately under the skin on the back of cattle, on either side of the spine. Each of these contains a grub which is the larvae of the ox or warble fly. When the grub has fully developed,a small opening appears in the swelling and the grub falls to the ground, where, if coditions are suitable, it hatches into a fly within six weeks. However, in New Zealand the conditions have always proved adverse to the grubs. The presence of these swellings under the skin seriously damages the hide of the animal and affects its commercial value. The Dominion’s safety is due to the fact that grubs leave the animal at the wrong time of the year (the disease can be found only in imported stock), and therefore die.

However, the department has laid down a procedure for treatment of the disease which is effective. The egg and grub are upon the animal for eight months. Hence, a system of quarantine, unless of great length and heavy expense, will not 'ensure the grubs not entering the country. The period of detention is, however, lengthened when the grubs make their appearance upon the animal while it is in quarantine. Stock which leaves quarantine without exhibiting any symptoms of the disease are also kept under observation by the district inspector of stock and if any symptoms appear the neqessary steps are taken to destroy the grubs before they become free. This is continued until a long enough time has elapsed for any warbles to have appeared upon the beast.

The grubs, once they reach their final stage, are easily destroyed by i being squeezed out of the small aperture at the top of the swelling and killed. This, states the department, is the surest way of dealing with them. Fresh swellings may appear over a period of months, so a watch must be kept. Other methods of treatment are to inject into the openings one of several preparations, Derris powder, in j the proportion of one ounce to a pint i • f water, well shaken up; and a one [ in twenty solution, in water, of silver > nitrate. Another method is to plug ; the aperture with mercurised oint- j ment; but squeezing out is the sound- j est way, . {