INSECT PESTS

Evening Post, Volume CIX, Issue 43, 20 February 1930, Page 26

INSECT PESTS

HUGE ECONOMIC WASTE

SCIENCE TO BE CALLED IN

(From I'The Post's" Representative.)

LONDON, Jflth December.

In furtherance of the work for Empire food, tho Bmpiro Marketing Board has assisted the linpciial Collego of Science to acquire iaboratories at Slough where an intensive war against insect pests will bo planned. The laboratories are now almost completed and. scientists have been appointed to tackle tho pressing problems of insect control. Dr. J. W. Munro will bo in charge of the work.

Ranged against the walls at the now headquarters are cages containing drab but devastating moths and beetles which-live on stored cocoa, dried fruits, flour, spices, arrowroot, and anything elso they can get at. These insects attack food and raw materials wherever they are stored—in packing houses, in ships, in docks, and wharves, in warehouses, and even in factories, and have so far defied every effort made to eradicate them.

One of lihe most important is a small • greyish insect called the Cacao Moth. Tho larvae of this moth bore their way into cocoa beans, and later spin webs over the sacks. In this way they do thousands of pounds worth of damage; for they reduce the price of "infested" cacao, even when it is hardly touched by the insect, by spoiling its market appearance. The cacao moth, also, sometimes spins its web on and in arrowroot sacks. Although it will not actually eat arrowroot, the insect soils the product and infested sack's fotch a very much lower price than their true market value.

The cacao moth is extremely hard to control because it occurs in all the cocoa growing countries of the world, so that new supplies of it are continually ai-riving in London and other ports. -Even if the adult moths and caterpillars can bo killed, tho hundreds of eggs laid by each female moth are too small to be seen and escape destruction. The Gold Coast, which produces about half of the world's supply of cacao, is, of course, particularly interested in the control of the moth, and also of certain moulds which .attack cocoa beans.

A survey recently undertaken by a scientist employed by tho Empire Marketing Board, with the object of finding out to what extent tho cacao moth occurs in. some of the London docks, is published by H.JI. Stationery Office. It is hoped that, by means of surveys followed up by a study of the insect's life and habits at the new Slough laboratories, means may be found by which tho pest may be gradually eliminated. A DESTRUCTIVE BEETLE. Another pest is Lasioderina, a'beetle with a truly amazing palate. Cayenne pepper, ginger, opium, liquorice, tobacco, furniture upholstery, yeast, curry and nutmegs are only some of the foods it really enjoys. "As a result of a study of this beetle, both ■in England and in the United States, 52 different foods have already boon found upon which it thrives. Then there is the moth called Plodia, a constant source of trouble to the dried fruit trades, and a beetle called Araecsrus with a taste for nutmegs among other things.

Tho consumer of food knows nothing of these insects, because in no case do they survive tho manufacturing or packing processes and find their way into tho finished product. Nor do they have any injurious effects from the health or sanitary points of view. Nevertheless, tho consumer eventually has to pay something for the board and lodging of these millions of uninvited guests. Not only do they lower the market price and give rise to serious losses to growers, but they cost a lot of money in efforts to control them, such as fumigation and re-con-ditioning, and cause laTge losses to the manufacturer, who has to throw away damaged material.

Dr. Munro and his team are breeding up large stocks of insects to experiment with. First of all more must be found out about their life-histories, and how they are affected by heat and cold.' Dr. Munro points out that very little is known of the life-histories and physiology of many of our most serious pests, although . learned entomologists have produced volumes about their structure. Then control measures such as fumigation by poisonous gases, sterilisation, and freezing will be tried.

A firm of confectioners recently asked for Dr. Munro.'s help in combating an insect which was burrowing in the almonds with which tKey had hoped to decorate their cakes. Fumigation and heating were alike impossible because they spoiled the flavour of the almonds. Dr. Munro suggested freezing tho nuts, and this was found to-be niost promising, as the .insects can be destroyed and the nuts left unharmed. Now a refrigerator is being installed at Slough to test out control of pests by means of cold as well as by heat and gases.

The war against these enemies of commerce will be a long one, because they are so firmly entrenched at the ports. But with combined attacks on all parts they may yet be driven from thei-r strongholds.