The Grass Grub.

Waimate Daily Advertiser, Volume XIV, Issue 67, 30 October 1911, Page 1

The Grass Grub.

BROWN BEETLE WILL ATTACK STRAWBERRIES.

SUGGESTED METHOD OF ' DESTRUCTION.

The following interesting particulars of an experience in fighting the grass grub has been furnished by Mr J. Mopdie, of Christchurch, for the Agricultural Journal. It should be pointed out, however, that Mr Moodie's method of dealing with grass grub has reference to ploughed land that is going to be put into crop, and no doubt the use of a toothed roller would be very good for the purpose. It has to be remembered that our chief difficulty with grass grub is in pasture paddocks and paddocks that have been in grass some years. LasT season, of course, great damage was done to newly sown grass, but that is 1 not generally the case, at any rate with spring sown grass. So far as autumn sown grass is concerned, thorough and continuous cultivation from November onwards helps very largely to reduce the pest. It is more than doubtful if the grub would deposit any eggs on fallow ground that was kept well worked during the period of its ovipositing—i.e,, from November to the end of December. Mr Moodie writes:-As is generally known, the grub is the larva of the brown beetle that is found flying at dusk in large numbers during the months of November and December. At this time the beetles lay their eggs in-the soil, generally at the root of some favoured"plant the leaves of

which they have been devouring. Should a plantation of strawberries be near by, for a certainty it will be invaded. I have found ss many as two dozen eggs laid about an inch below the surface at the root of a strawberry plant. There must be great mortality amongst the young grubs, particularly in the stiff soils, probably through failure to obtain a sufficient supply of food, as 1 have rarely found as many as half a dozen grubs at the root of a plant in a square foot of soil. The young ones grow rather slowly ■, at the end of winter they are rarely half-grown. As a rule it is the second season, and, 1 am inclined to believe, often the third season before the grubs reach the chrysalis state and emerge as beetles. One practised method of destroying

them is by means of bonfires at dusk,

but unless concerted action is taken at one time and over a considerable area there will be V.p permanently good results. In land, however, about to be sown down in grain or grass the grubs may be completely destroyed by the following means: The implement required for the purpose is what used to be known as Norwegian harrows or the rotary harrow. It consists of two parallel circular cast-iron toothed rollers, the teeth or tines of which are about Sin, long and set about 4in. apart. The rollers are carried on a two-wheeled frame, and when not in use are raised off tbe ground by means of a lever. As the grubs are rarely found more than Sin or Sin in below the surface, the ground may be ploughed about 6in deep, and levelled with any ordinary harrow. Two to four strokes of the Norwegian harrows must then be given. To make the implement effective at least three stout horses are required, and they must be driven along smartly. As the

rollers are set so the teeth of the rear one revolve between those of the front one, the whole soil to a depth of 6in or Tin gets so thoroughly crushed and

pulverized that neither worm nor grub can escape, but a week later they will be found to be discoloured and dead owing to the rupture of the internal organs. By the above method for five years I had complete success in coping with the grub, and that on land so badly infested at first that the soil could be rolled up like a mat. There is not the slightest doubt as to the success

of this plan. As a matter of fact, at a time when the grubs were exceedingly destructive in the fields adjoning

mine I planted out about thirty thousand strawberry plants, and did not lose one, although the year previous

the same two acres were completely

eaten out. Three or four strokes of these harrows may appear a little expensive, but to a farmer about to sowJdown a

paddock in grain or grass it is a mere trifle when he can rely on a full crop

or a complete sole of grass after their use, and there is no doubt that the extra cultivation would in a great meas-

ure pay for itself apart from the de-

struction of the grubs. It is generally two or three seasons before they again

do serious damage. - The following method of preventing the grubs spreading in newly sown

down grass land, to ray mind, bears the evidence of practicability on the face of it, I have not tried it, but certainly think it well worth trying. As is known, the beetles lay their eggs at the roots of the grass and

near the surface in November and De-

cember. If, tnerefore, at the December the land were given a thor-

ough rolling with a Cambridge roller or with a Norwegian harrow made specially for the purpose, with short stubby tines about 2in long, practically speaking' all the eggs would;-be destroyed. In the, State and private nurseries, where in. season thousands of forest tree seedlings are destroyed by the grub, such an implement would be invaluable. For strawberry growers at present there is .no better. The prices paid for strawberries here are exorbitant and chiefly, on account: of; the the grub, ; Should any [t polht|>hoV made shall be. afford;