SERIOUS PEST

Evening Post, Volume CXVII, Issue 75, 29 March 1934, Page 16

SERIOUS PEST

EUKOPEM EAEWIGS

NO REAL CONTROL

ITS HABITS AND HISTORY

"Earwigs, like the poor, seem to be always with us, only in greater numbers, than ever before," writes a Lower Hutt correspondent who wants to know if wo "can do anything about it." The power of the Press is undoubtedly great, but if it were: great enough to suppress the earwig nuisance it would have undoubtedly long ago been done, for it is now somewhere about forty years since the earwig first became established iv New Zealand as a firstclass pest.

: This country, as a matter of fact, lias always had earwigs of its own, there being threo native, species. One of these, a much bigger insect than the imported variety, is confined to the seashore, and- none of the three, the other two also being larger than the imported species, are of economic importance. It is the common littlo European chap that infests dahlias and does such damage in gardens and orchards, especially in the South Island. Exactly how or -when he got to New Zealand no ono knows, but the transport of earwigs from one country to another is a comparatively easy. matter. The earwi" is' nocturnal in its habits, and it easily remains concealed in fruit (jr packing material or in crevices in cases. That it did not' reach Now Zeaalud beforo the early nineties is more to lie wondered at than the fact: that it is now numbered among our too many unwanted immigrants. Once in tho Dominion, the. European earwig found the matter of transport from-ono district to another very easy, using rail and steamer like any other tourist, but without paying, any fares. In fruit cases, timber, sacking, etc., in railway yards, packing houses, and sheds they :just sit and await human agency for. transport ' over oceans, rivers, and .mountain ranges which' under normal circumstances might restrict' their, wandering; The earwig has not. been slow to: tako advantage, of.manj's assistance in. order to.spread far and wide. Climate in some instances might have checked its spread, but hero again man,has materially aided tho earwig. Central Otago' is an example of this. , Barren valleys, which normally would hardly graze • one earwig. to the acre,; have been converted into highly productive. ;areas by means of irrigation; and earwigs there number almost millions to the'acre; NO CONTROL BY PARASITES. __ Since its arrival in New Zealand tho European, earwig: has become thoroughly Established -wherever it lias found suitable environment, which is practically, everywhere. Such a pest has'it become that the Cawthron Institute for the last ten years or so has been wbrlcing at the problem of establishing paraBites to check it, but with no marked success. One of the parasites experimented with lays its eggs on the "back of-the earwig, but the earwig does no t appear to relish this, and, with a contortion which would make a fortune in the circus ring, arches its back so that the pincers in the tail.can lift off,the offending eggs. The other parasite lays its eggs on the food which the earwig is supposed to eat, but the earwig, although omnivorous (and even cannibalistic in hard times) is discriminating in its food and apparently it refuses, and "with some justification, to ,eat food infested with eggs intended for its destruction. TRAPS MORE USEFUL. Control by parasites, therefore, does not seem a very practicable proposition. Poisoned baits will work to a. limited extent and traps will account for a number of the pests. These traps are of various kinds and usually very simple. Ono plan is to place straw in a flower pot and to invert this over a stake driven into the grouud. The earwigs, after their nocturnal marauding expeditions, seek shelter in .the pot during the day when they usually rest, and it is a simple thing for the trapper to shake the contents of the: pot into a bucket of boiling water. One medium-sized pot may catch as many as a hundred earwigs in one night, for apparently they do not wind overcrowding in their sleeping quarters: Pieces of folded paper or sacking left about on the grouud are similarly used by earwigs as sleeping quarters, and one method of keeping them in check is not to leave anything lying about under which they can find shelter during the day. This advice is very much easier to give than to carry out. • , Trapping operations will not be very effective if one's neighbour docs not carry on a similar campaign. To get rid of the pest in any one locality would, mean a concerted effort on the part of everyone, but such concerted ■effort as would, be needed to- be effective would be very .difficult to' get. ITS NAME AND HISTORY. The earwig-'s name, according to the best authorities, originated from the Anglo-Saxon word "earwieya," which means "ear creature.", The name appears to have the same significance in • nearly all European • languages, pointing to the' wide-spread belief that earwigs crawl into the ears of sleeping persons. There are, however, no grounds to substantiate any such belief, except that the earwig will go into any crevice for shelter during the day, like any other nocturnal insect. That earwigs cannot fly is another popular delusion. Earwigs do fly, although they aro not,.. often seen so doing because most of their aviation is indulged in at night. The insect has neat, efficient wings most cunningly concealed. Earwigs arc readily recognised 'by their characteristic wings. Tho fore wings are small leathery coverings which extend a short way along the back,."while the.hind wings aro large, and when not in vtso are completely folded beneath the fore ■wings. As to the forceps or "pincers" they vary in shape according to the sex. The life history of the earwig as passed, in New Zealand is not without interest. The winter is passed by the earwig in. tho adult and egg stages underground, or in some- other suitably moist and sheltered place. Both sexes hibernate, but,the female lies with her batch of eggs. If by chance the eggs are scattered, the female will, gather them'together, carrying due at a-time in her jaws. During August and September, as a rule, the eggs hatch and tho minute white earwigs swarm in the ground. Earwigs are nocturnal, and on the. first night after hatching tho young earwigs leave the grouud and feed upon the tender parts of plants. Small holes are eaten in leaves, and pollen and stamens of flowers are alsoeaten. As the insect grows it sheds its skin four times, and after each moult tho developing' wings, become more conspicuous. Maturity' is reached about November and December. It is at that time that the earwigs attract attention, as earlier they are much less conspicuous. The hibernating males and females live for some time after the hatching and another batch of egga is laid after a mating in September or October, b'lit the adults concerned then die.