D.D.T. And Grass-Grub Control

Press, Volume CV, Issue 31042, 23 April 1966, Page 9

D.D.T. And Grass-Grub Control

Before any farmer abandoned use of D.D.T. for control of grassgrubs he should call in an authority ,to determine whether or not resistance to the insecticide was operating, the fields superintendent of the Department of Agriculture in Christchurch, Mr A. R. Dingwall, said this week.

Where resistance had not been proven Mr Dingwall said it was the department's policy and the standard recommendation that D.D.T. should be used.

Mr Dingwall said that some farmers might have interpreted reports of resistance to D.D.T. in grubs as indicating that D.D.T. had more or less come to the end of its usefulness in Canterbury, and Mid-Canterbury in particular. From what he knew resistance had been proven in only a small number of cases. At the present time the research division of his department in conjunction

with the Entomology Division and the farm advisory division of his department in Mid-Canterbury were conducting a survey to see how widespread resistance was, and until such time as the results of this survey came to hand the use of D.D.T. must remain the standard recommendation.

As he saw it, Mr Dingwall said that the position was likely to be that there would

be a small low percentage of cases of resistance throughout Mid-Canterbury, but that otherwise D.D.T. would remain the standard treatment for grass grubs. In South Canterbury, Mr Dingwall, said there was a lot of pasture damage at present but this was due to porina infestation and it was necessary to be certain that damage was really due to grass-grub and not porina.