APPLYING D.D.T. BY AIRCRAFT

Press, Volume XCIV, Issue 28050, 18 August 1956, Page 9

APPLYING D.D.T. BY AIRCRAFT

NEW METHOD EVOLVED

NO ADMIXTURES REQUIRED A new method for applicatidn of D.D.T. against grass grub in pastures —those topdressed from the air—without the admixture of lime or fertilisers to provide sufficient bulk for spreading, has recently ben developed in the Dominion. In the new method finely “micronised” D.D.T..is attached to (coated on) small but heavy particles of an inert carrier to form what is technically known as prills. These prills are ground marble pellets about the size of white clover seed and are coated with D.D.T. The carrier particle is sufficiently heavy to resist wind draft, with the result that, when applied from aircraft, all the D.D.T. is carried with it and falls on the target, that is on the paddock under treatment. Advantages Claimed The advantages of the new method, which is shortly to be tried out in Canterbury on aircraft with specia*. attachments to ensure even distribution, were demonstrated recently on a 20-acre padodek at Mr J. D. Hopkins farm near Wyndham. Wind velocities at the time of application were considered too high for sowing superphosphate by aircraft yet the D.D.T. prills were, the writer was told, applied evenly over the area from an estimated flying height of 60 feet. Indeed, trials have shown that variation in height of flying above 30 feet does not materially affect the pattern of distribution, thus overcoming a major difficulty in the application of D.D.T. The prills are sufficiently hpavy to bounce off foliage and fall through to the soil. Thus there is little chance of any D.D.T. being picked up by grazing stock, nor is there any hazard to beneficial insects such a bees, even though clover or weeds are in flower at time of application.

Fall One Inch Apart When applied at 201 b an acre the D.D.T. prills are about one inch apart, or less, and give the standard dosage of 21b of active D.D.T. an acre. The

"micronised” D.D.T. is readily washed off the prills by water and consequently becomes dispersed in the soil by rain. There seems little doubt that this new development provides a more accurate method of treating pastures. Not only is the D.D.T. easier to apply but the full dosage falls on the soil where it is required. The development of D.D.T. prills is the outcome of research by a New Zealand manufacturing company. It is understood that limited quantities of D.D.T. prills will be available soon and that farmers, particularly on the hill country, will have a chance of testing this new product for themselves. Lincoln College is at present exploring the possibility of using these prills for land-based equipment, but it is too early. to decide whether the granules lend themselves to that purpose.