INSECT PESTS

Hokitika Guardian, 9 January 1928, Page 4

INSECT PESTS

INTRODUCTION OF PARASITES. WELLINGTON, Jan. 6. In a lecture entitled “ Some Insect Friends of the Gardener,” illustrated by lantern slides, which Mr D. Miller, Government Entomologist, delivered before the Nurserymen’s Association on Thursday, the lecturer stressed the fact that just as life was a constant struggle between men, so the career of the insect was a struggle against rivals. Insects were responsible for a great annual loss, especially in an agricultural country such as New Zealand. One of the most important pests was the pear midge from Europe, where

it was not a bad pest; and its natural enemies were consequently unknown, xne nudge laid its eggs in the unfolded pear leaf which curled up, died, and fell to the ground where a little grub furrowed. It had a life circle of a month. Research had revealed a useful insect called the platigastbr which destroyed the midge. These platigasters were being brought into New Zealand and distributed, and the orchards where they were at work were now showing a full crop of leaves. The mealy bug, which sucked the sap from plants, was now being attacked by aphides from California and Australia. The cabbage aphis and others could be attacked by “ blackleaf 40 ” or kerosene emulsion. A small wasp-like insect laid its eggs in the body of the aphis, but unfortunately a third insect also laid its eggs in those of the wasp. Ladybirds are the enemy of the aphis, but an enemy in its turn attacked them. The hoverfly laid eggs among the aphides and the patched grub (headless and blind) devoured many aphides.

The giant borntato pest on pine trees attacked only weakly trees, boring holes in the tree trunk. The hatching grub enlarged the hole, in Europe this pest was attacked by parasites, including one with an enormous long ovipositor wftTi which it laid eggs in the embedded grub. This helpful insect was, however, yet to bo introduced.

“ Parasites, however,” added Mr .Mailer, “are only a partial aid. Spraying is still essential in orchard practice.”