THE COLORADO BEETLE.

Nelson Evening Mail, Volume XII, Issue 223, 20 September 1877, Page 4

THE COLORADO BEETLE.

{Auckland Herald.] During the last few years the attention of our readers has frequently been drawn to the ravages committed by a small beetle, commonly known as " the Colorado potato beetle, but known to science as Jjoryphora deemlineata. It has been known to science as one of the coleoptera of North America, for the last fifty years or more, but it is only within the last eighteen or twenty years that its behavior has attracted particular attention. When first found umbng the eastern spurs of the Rocky Mountains, in the region of Colorado or adjacent territories, it was seen to feed on a wild species of the potato pla it, the Solatium Ostratitm. At that time the cultivated fields of the American citizens were a very long way from this district, and it never occurred to agriculturalists or even scientific men to make any experiments with ibis beetle to ascertain whether its food was restricted to the plant it was found on, or whether it would feed upon the cultivated potato ( Solatium, luberosum), and for many years no importance was attributed to this member of the large Coleoptera family. But, as years rolled on, the white man pushed bis settlements further into the red man's hunting grounds, and the potato was one of the crops which (ha pioneer settler never failed to cultivate. By-and-bye the cultivated potato came in contact with (he region wherein the Doryphora had been for so many years an inhabitant. These pioneer settlers soon found that they had to encounter an enemy, whose destructive character they knew not of. The cultivated potato was found to agree admirably with the beetle, and an abundant supply of food being thus provided in the cultivated fields of the pioneer settler, it began to increase with wonderful rapidity. The multiplication of this beetle was no longer prevented by the insufficient or precarious supply of food formerly found by preying on the wild potato— native to that district of the American Continent— and it showed its kindness to the settlers for this change by soon beginning a mirch from its mountain borne to the cultivated plains £0 the eastward. It was at this stage of its history that tbe attention of scientific men and working farmers was alike directed to its movements. Year by year it reached further eastward, and alao extended its field of operations north and south— in fact, wherever the cultivated potato was to be found. Within the last twenty years it is estimated that it has overrun an extent of territory more than a million square miles. About three or four years ago it reached the Atlantic coast, and much uneasiness was created in the minds of British and other European farmers about the possibility of it crossing the Atlantic, and ravaging the potato fields of Europe. This fear was but too well founded, although some at tbe time looked upon it ag a very improbable occurrence, aa this beetle only feeds upon the leaves and stems of the potato, and will not touch the tuber; But the journey has been made. So rapidly does it carry on its work of destruction, that a potato field is soon almost completely destroyed if the beetle is left unmolested. It multiplies very arpidly, the female laying eggs at varying periods for forty days, until the eggs laid by a single specimen may aggregate' as many as 500 to 1000. In about 38 degrees north latitude there are three broods per annum, and from thirty to forty . days after the egg is deposited it passes through all its stages of transformation and becomes a beetle, the pupa Btate being assumed under ground. As to the countless myriads which might soon be produced wherever it obtains a lodgment, Professor C. V, Riley, the chief entomologist for the department of Agriculture, Washington, who has made this animal a long and careful study states, " The prolificacy of the species may be imagined when it ia remembered that the progeny of a single female may exceed 100,000,000 in the course of a single season! The beetle feeds as well as ' the larvje, though not so voraciously." Such is the productive energy of the insect which the farmers of Europe have now to fight, for it is an ucdeniable fact that it has been introduced into Europe. During the last summer it was found in ihe pefect state in a potatoe field at Mulheim, near Cologne, and when the fact was reported to the Government, the most vigorous measurea were taken to "stomp out" the new pest to agriculturists. The field was at once covered to some depth with sawdust and tanning hark, which was then saturated with petroleum and set on fire, the owner being recompensed for the loss of his crop. If the Government in other European countries in which it might appear were to adopt equally vigorous measures for dislodging the intruder, a long time might elapse befora it secured a per- j manent and hurtful lodgment; but we fear the fight will be a vain one, for when once a creature, which multiplies with such rapidity, has bred and been perfected in a country, it is difficult to destroy every single specimen, and even one impregnated female would, in a very short time, provide an abundant supply. The German Government have done more towards fighting this creature than destroying the crop in tbe firrst field it was seen in in that Empire. They have issued full par- j ticulara of (he insect in all its changes, and have prepared colored models of it, go that farmers and others might, recognise it readily. We learn that his j

Honor Mr Justice Gillie 3 has received from Sir Julius Yogel, Agent-General for the colony, two models of this celebrated potato beetle in ita various stages of development, for the purpose of acquainting the public geaeratly with the appearance of this terrible insect peat. One of these models will be deposited at the Museum in Princes-street, and Ihe other at Mr Alfred Buokland'a store, in Qtieen-3treet, for the inspection of all interested. As the insect has appeared on theContinenfc of Europe, and looking to the frequent communication between this colony and America, it is possible that the pest may be introduced here; and it ie, therefore, very desirable that all persons should become familiar with its appearance, so as, if possible, to check its progress at once in the event of ita introduction. The (hanks of the community are due to Sir Julius Yogel for his forethought in the matter. The practical information which these models convey is welltime:), especially when the character of the insect is considered. A few lines from a memorandum, prepared by the Department of Agriculture, Ottawa, Upper Ornado, will show how liable we in New Zealand are to have it introduced amongst us, seeing that it has crossed the Rocky Mountains on its westward march. The memorandum states . — " The difficulty cannot be but self-evident when the habits and modes of progression of the insect are examined. Not only does it move by flying, and by navigating — so to speak — smooth water, but it also travels on common vehicles, railway carriages, and platforms, on decks of vessels, especially duriog the months of August end September. la localities fully invaded the beetlee may be Been creeping on side- walks, bridges, and wharves, crawling up buildings, occupying fences, lodging themselves in every crevice, penetrating houses and dwellings, ascending and occupying vehioles of all sorts, finding their way into boats and vessels, placing themselves on any aad every article, and being found alive after along sojourn in situations where there would seem to exist no chance for them to. find any subsistence." Such is the activity of the enemy now vigorously attacking the industry of man. It has not yet appeared in Canada, but it has reached the State of Maine, and the Canadians expect it to ahow in the Montreal district next summer* In the districts of the United States which have been overrun with this pest, various remedies have been tried — mechanical and chemical. It is found that during hot weather, if the potato tubers are shaken, and the larvjß knocked on to the hot ground, especially at midday, great numbers of them perish, and the eggs thua shaken off the leaves invariably perish. But the most efficient remedy has been found in what is known as " Paris I green" — arseniteofcoppeer. This deadly poison is used either in a dry or a liquid state. If used aa a liquid, about a tablespoonfuJ of the powder is dissolved in about three gallons of water, and the potaoes sprinkled therewith. When used in a dry state, which ia the common plan, one part of the powder is mixed with about twenty-five to thirty parts of flour middlings, lime, &c, and the mixed powder dusted on lo the leaves and stems of ihe growiog crop. A man can thus dnst about eight and a half acres per day, and about 300 tons of Paris green is used annually in the United States principally iv killing this little, but destructive creature. The true remedy will probably be found in another class of insects preying upon it, and thus the forces of Nature will react upon each other, and man, by encouraging the one and ailing ia destroying the other, will obtain the advantage. It has been found that the larvie of various members of the large family of insects, known as ladybirds (Goccinellidce), greedily devour the eggs of ihe Colorado potato beetle, »*nd tbe "spined soldier bug " {Anna spinosa) Jaitack both the egiis and larva;. These and other natural enemies. will doubtless increase, in the j course of a few years and practical/ exterminate the now dreaded beetle ; but that will not ranke the loss which it now causes lees eaßily borne. The Government ought to obtain an abur* daot supply of the models sent by Sir Julius Yogel to Mr Justice Gilliee, and supply all the Custom House oflicere with specimens, so that they might be able to recognise and destroy the true beetle when Been upon any of the wharves, or the vessels which might have come from America. They might also obtain living specimens of tbe natural enemies of this potatcdeatroyer, and give them their liberty on arrival in the colouy. These will keep a more constant and faithful watch than even man.