The following letter regarding the best methods to adopt to combat grass grub was submitted to the Napier Borough Council last night by the instructor in agriculture MR H. Woodyear-Smith):—
“I noticed with interest that the public grass parks in Napier have suffered badly this season from ravages of grass grub and that with the idea of combatting this pest, the parks have received a dressing of superphosphate and have also been rolled. I would like to point out one or two details which may prove of interest and assistance.
“The grass grub (Odontria Zealandica) holds the same position as the June beetles do in Europe. They make as beetles, two main flights, the first in November and the second in March. During those months especially lawns and pastures should be kept well down as the grass grub beetle always chooses a spot to settle where the grass is appreciably long. For the destruction of grass grub on small areas bisulphate of carbon may be used. Bisulphate of carbon is a highly volatile solution, exceedingly heavy and costing about 2s to 2s 6d per pound. The solution is used for the control of the grub in this way:
“Small holes about six to eight inches deep are made all over the infested area and filled with the solution and then promptly blocked up. It can be easily seen that this method is economically unsound as a treatment for large areas.
“The best methods to adopt for large areas are:—Keep the grass short, especially in November and March. If the grub has taken possession, top dress heavily with sulphate of ammonia and if the weather is dry, water the effected portions after the sulphate of ammonia has been applied. Roll with a heavy roller, the heavier the better, this will help consolidations. Some local farmers, I understand, have had success from the use of White Island manure. Roll the ground repeatedly and if necessary give further dressing of sulphate of ammonia. This treatment will to a great extent control the grub.
“I would like to point out that a great deal depends on the treatment a sward receives before grass grub has taken possession. Careful treatment will often keep the sward entirely free from the pest. I would also mention that the biological control of grass grub is being tried out by the department and if any definite developments occur in this direction I shall be pleased to advise you.”
The letter was received by the council, and it was decided to thank the instructor for the information.
The Grass Grub
New Zealand Herald, June 30, 1932
Sir, — I see Mr. Smallfield, of the Department of Agriculture, says nothing can be done about the grass grub that is affecting some farms over Te Aroha way, so possibly my experience may be of some use.
I have a paddock which for some years, though it gave good feed in the spring and early summer, was always the first to brown up in the dry weather, and also showed a few bare patches characteristic of grass grub.
Last winter I gave it three strokes at different angles with a good penetrating grass harrow, at the end of which the paddock looked pretty sick, the short-rooted grasses eaten off by the grub coming away in chunks, and thousands of grubs were exposed, to be eaten by starlings or die of exposure.
The paddock was a month or more in recovering and was subsequently shut up and used for ensilage and hay.
Although last summer was particularly dry it remained comparatively green throughout and threw quite a lot of feed and when harrowed in the autumn showed very little grass grub.
The treatment, I should say, is well worth trying by anyone whose land is not too far gone; anyway, it costs nothing beyond the labour, which is a consideration these days when none of us has any money.