FIGHTING PESTS

Hokitika Guardian, 7 June 1932, Page 3

FIGHTING PESTS

THE LOST LADYBIRD

SYDNEY,' May 25

There ha v£ arrived in Australia 81.,300 r shoek ■ troops from abroad,, not fob wair in its ordinary. grim acceptance, hut for an aggressive attack, on a nation-wide front, on two. of this country’s biggest pests—the St. John’s. Wort and scate 1 dii ' fyiiit trees.

These “shock 'troops’’ are. actually 81,000 eggs of one' of the species' of beetles, for the purpose of devouring the, St. John’s Wort, and 300 eggs of a fly to destroy, scale on fruit trees.; This effort to fight pests with parasites follows the successful experiments, in Australia with the insect cactoblastisy in keeping down prickly pear. It is pointed out that parasites have hyperparasites, and that these again have tertiary parasites, and that it is for ths reason that the 300 fly eggs will after hatching, be, plated in entomological quarantine to free them from their own parasites, and so give them a greater chance to do the work with'

which Australia is confidently 'entrusting them.

Australia is now also experimenting with blowfly parasites from abroad, because there is a natural parasite on tlie sheep blowfly in the Commonwealth to-day which is prevented from' keeping the blowfly , down, since th’C 1 parasite’s own parasites prev upon it.

The interesting fact is recalled that an Australian ladybird was introduced into New Zealand to exterminate an orchard; pest. It is stated, however, that the pest took refuge in gorsc, where the ladybird would not follow, and that the latter then either died or flew away into the mountains. When a beetle that feeds on a weed pest, such as St. John’s Wort, is introduced, a long period of testing in the Laboratory is 'essential. This is to make sure that it will eat the pest, and nothing else. Cactoblastis, for example, it is pointed out, has the virtue of dying when its natural food prickly pear, is all destroyed.