The Chronicie PUBLISHED DAILY. LEVIN. SATURDAY, FEBRUARY 7. INSECT PESTS.

Horowhenua Chronicle, 7 February 1914, Page 2

The Chronicie PUBLISHED DAILY. LEVIN. SATURDAY, FEBRUARY 7. INSECT PESTS.

I llokowiikma County has been planted witli trees iairly extensively in .sonic parts, and there an; many plantations of trees being nurtured in some districts. What wit]] imported pests and the native ones, 1 lie lot of every grower (whether he specialises in flowers, fruits, vegetables or trees) ( is frough t, with vexation and losses. One ol' this recent troubles of aborieulturists has been causeif by a native brown -beetle, which feeds preferentially on young larch trees, but is not averse from destroying any tree seedling that conies in its path if larch trees are unavailable. Any local settlers who have been puzzled by n. mysterious dying-oil' of their young trees may find light from a refenee made by the Umler-Secre-tary of Lands in his latest report on the afforestation operations of his Department in the Rotorua and other nurseries of the North Island of New Zealand "For some years past the seedling larch ' have been attacked by a native brown beetle, the larvae of which feed upon the succulent- roots of the plants. The destruction of trees caused by this {test was slight at first, but during the last two seasons it has been very severe. It was observed that the damage first commenced in the autumn, when the seedlings were about five months old. ' At this period the leaves of many of the plants become yellow, and upon investigation it is always found that such plants have been ring-barked just below the surface of the ground. In the spring the seedlings start away into growth, and to all outward appearance they give promise of doing well, but as the weather becomes dryer and warmer it is soon apparent that something is wrong: the leaves lose their healthy green appearance, many drop off, and the remaining ones are only about half the usual size. Plants can be pulled from the ground with the one finger and thumb, and if is found that all the soft roots have been eaten off, leaving only the bare tap-root and the stump ends of the secondary roots. Continued dry weather always results in the trees which are attacked dying out m patches. The beetles, which first make their appearance about the beginning of February, feed upon the leaves of the trees, but the d;unage done in this way is not as great in comparison as is that wrought by the larvae upon the roots. During the year much information has been gleaned about the life-history of this beetle, which has ITeen fully described in the Journal of Agriculture of March, 1 !)!•'>,' by Mr A. 11. Cockayne, Government Biologist, under the name of odontria puncticollis. Several methods of control have been adopted, and from the knowledge thus acquired there appears no reason to fear any serious losses in the future. Spraying the trees with arsenate of lead and other insecticides at the period when the beetles were on the wing was not productive of any appreciable good results, and fires at night were similarly ineffective. There seems reason to believe that the wind has an influence upon'the direction taken by the beetles on the wing- in search of a suitable feeding and breeding ground, and in view of this the present year's crop of larch was sown as far as possible from the last year's crop, and j£i a direction at a right angle to tin? prevailing winds. This crop of larch has been protected, too, with a covering of thin hessian. and'so far only one beetle has been foil in! amongst the trees. The results of these precautionary measures are being eagerly awaited, and it is confidently expected thai they will reduce the destruction of trees :o a minimum. The losses amongst the two-year-old seedling larch amounted to about -100.000 the result of the damage by grubs combined with an unusually dry season. This insect seems to prefer larch before any other tree, but it has been got in considerabl. • numbers in white-pine (pinus strjbus) and Douglas tir. Hods of Corsican pine and pin us ponderosa growing alongside of infected larch-beds seem to be perfectly immune from attack. '