A NEW ENEMY TO THE POTATO.

Waikato Times, Volume VI, Issue 318, 28 May 1874, Page 2

A NEW ENEMY TO THE POTATO.

1 wish to say a few words about an enemy which threatens to lnv waste one of Europe's most valued esculents, the potato. For a long time North America hae had to contend against two foeß, « Inch devoured the early shoots and leuves of thfr potato, and thus destroyed the hopes of the farmer and gardener. These were beotlos belonging to the same family as the Blister-fly, and n%\neALytta atirate(or vittata) and Gantharis viniaria. They can be(kept within bounds ; but of late a third beetle has appeared among us w Inch really threaten! to drive the potato out of cultiration al together. It bears the name of the Colorado Potato-beetle \ (Dorypkora decem-punclata) ; and should it once reach the -Atlantic coast, and be carried unobserved across the ocean, then — woo to the potato-growor of the old country ! A mun must witness the myriad legions of this insect, and the ravages of the never-tiring larvse, in order to form an idea of Iho ternblo danger with which Europe is threatened. For myself, judging from the tenacity ot life exhibited both in its larval and perfect condition, I have not a doubt that it w ill soon overstep the bounds of North America, and make a home for itself in other lands. Its true domicile i* in the Rocky Mountains, where it feeds on a species of wild potato, Stftinum roslrahtm (of Varoliniana), No sooner ( however, had the edible potato (Solatium tuberotum) been planted by settlers ut the foot of these mountains, than Doryphtia attacked it greedily ; the more largely its cultivation extended westward, the faster did its insect foe travel man easterly direction, and scatter itself over the land. In the | year 1859 it win located one hundred miles west ot Omaha I city, in Nebraska j in 1661 it showed ltselfin Iowa ; in 1865, not only had it begun to devastate Missouri, but it had crossed "the Mississippi in I linois, everywhere leaving behind flovjri-jliing colonies. In ISG > Indiana Win visited ; m 1870 Ohio and the confines 6f Canada were ren hod, also por^onn of Penaylva'ini and Now !forli ; ujirt.i&i < .tram'e .info Mas" ' «moht»ss"U«. vrosrotified. Dimng the j«a"r 1*71,"a great, aimy

of these beetles covered Llio m c 1) n.>itiii Urn in^iin.Lrij^d Lakt Erie on floating leaves :mil ■nmtl.ir iuhv nmnt nils, and in a tery abort tirue took |i.>--».— *i.m '>f tlio country between 8t Clairand Nn^n ni rv - '? >m; i^ot tuuafar, in spite of all efforts to stay Hn'ir pro r*>^ tlwre U «Tery reason to believe that bef-we I .n : w-n ill hear of them at swarming in the streets ol V »v V>ii» and Boston (as th«y olreidy awarm in the streets i»t M U»uid), and then their passage across tlw Atlnntio is a mci o matter of time. MoreoTer, the beetle in it* different atiy:. * w so entirely unaffeoted by the exti ernes of hwit and cuM, of wet and dry, which it has mot with hero, that I have no doubt it will care a» little for the changes of climate which occur in the temperate zono of Europe, and, once settled, will quickly become naturalized. The devastations <>f the Colorado beetle are all the greater, from the Inct of its propagating itself with extraordinary rapidity, several lots Jfollowinn euck other in the course of ihejeir. The first bitch of infant lary» appears towards the end of May, or, if the weather be mild, of April. In fact •carcely has the potnto plant shown itseJf above the ground, before the, insect, which has been hibernating during the winter, also wakes to life. The female loses no time in depositing from seven hundred to twolve hundred eggs, in clusters of twelve or thirteen, on the underside of a leaf. Within five or six days, according to the state of the weather, the larva; escapo from the egg, and^begin their work o£ devastation, which goes on for some seventeen day*, when the little creatures rotire beliw the foil, in order to undergo the pupnl condition. After a delay ot ten or iourteen days, the pei feet insect comes into being, and the business o-f egg-lay-ing commence* anew. In tins way, according to recent ob- I •ervations, three breeds follow each other; the last, as just slated, wintering below the surfuce of the ground. No description can do justice to the marvellous voracity of this insoct, especially in its larval state. When once a field of potatoes has been attacked, all hope of a harvest must be given up ; in a very few dayi it is changed iato an arid waste — a mere mass of dried-up stalks, — Hardxoick't | Science Gossij).