Research Into Grass Grub Problem

Bay of Plenty Beacon, Volume 13, Issue 9, 18 October 1948, Page 3

Research Into Grass Grub Problem

All aspects of the -grass grub problem in New Zealand are .the subject of a long-term major demonstration at the Cawthron Institute, headquarters of the entomology division fo' the Department of Scientific and Industrial Research. Study at the special sub-station at Ashburton indicates that soil moisture is an important factor influencing the ' abundance of grassgrubs. During the last dry season this was indicated by the low grub population and the retardation or development of the grubs. The annual report of the division says that experiments with insecticides have been undertaken against the grubs. and beetles. In the former no final conclusions have been reached, but it has been shown that a very marked control of beetles can be obtained. For example, in a field experiment carried out in conjunction with the Department of Agriculture, D.D.T. was used with good suits. But in any extension of this method on a wide scale consideration must be given to the influence of D.D.T. upon honey bees, especially in honey and clover seed-pro-ducing regions. Attempts are being made to find a reliable means by which flights of beetles can be foretold; upon this the safe period or sowing cruciferous crops depends. As many parasites of grass grubs occur in Australia, a special study of them is being carried out. One

species in particular which may prove suitable has been shipped to Nelson, where it. has been successfully reared on the most destructive species of New Zealand grass grub.