A STATE IN ARMS AGAINST A CATERPILLAR.

Press, Volume LIV, Issue 9835, 18 September 1897, Page 3

A STATE IN ARMS AGAINST A CATERPILLAR.

Fletcher Osgood in Harper's Magazine.

The State in arms is Massachusetts ; the caterpillar, a hairy creeper, spinner, and cruncher, soot-grey in ground - colour, dotted with crimson and bine. When fullgco\vu he ia thick and long as a pill-phial. He is hardy and appallingly prolific, and is named the gipsy-caterpillar, child of the gip3y-moth. This menacing forager of the Eastern Hemisphere wai brought over twenty-six years ago by a French savant in considerable numbers to Medford, a suburb of Boston, Massachusetts. The object is said to have been to cross the creature with the delicate silkworm, and so originate a robust silk-producing hybrid for America ; i but the statement has been gravely questioned. The scheme, whatever it was, came to nothing, and the gipsy-cater- i pillars, liberated from their netted enclosure by a gale, spread slowly over Medford, and then into adjoining and more distant towns. In nine or ten years from their liberation they had developed into a noteworthy local nuisance, and by 1889 they swarmed upon Medford iv irresistible hordes. Extensive tracts were swept clean. Grove 3 and gardens, fields, orchards, and tree-shadowed streets all felt the "fierce tooth" of the ravager. The sides of houses, walks, and stoops were black ; and the evil swarms, having devastated a district, inarched upon the next, and the next. Their presence surcharged the invaded neighbourhoods with a most repulsive stench. When the impulse of transformation drove these creatures in July to shelter, they huddled \inder whatever offered them protection about and even in the houses they had beleaguered. Here, casting their hairy coats, they soon changed into pupae ; these"about August evolved into moths, which, dying, as their nature is, soon after birth, left behind them myriads of hardy, fertile eggs to hatch by regular course in the following spring. The egg clutches thus deposited embossed their shelters with spongy ochre nodules, close huddled as the globules in fish spawn. The householders scraped them off by the peck. Additionally, eight brimming cartloads were removed by a small official force. Each gipsy e<*g cluster contains on an average about 600 eggs. During six •weeks of 1891, 760,000 of these clusters, within a restricted local district, were by official means destroyed. Not greatly legs than half a billion caterpillars were thus crushed in the shell. But this wholesale destruction did not even liberate the territory immediately threatened much less the outlying suburban regions into which the pest had spread. The careful reckoning ef science has demonstrated that the unrestricted caterpillar increase of a single pair of gipsy-raoths would suffice in eight years to devour the entire vegetation of the United States. In the ordinary course of nature (let Heaven be thanked for it!) such increase never is left wholly unrestricted. Still, looked at even in the most hopeful way, this outlandish invasion was a fearful portent to the entire nation. Let the " gipsy" once get fairly free of the bounds within which, as we shall see, the State of Massachusetts has up to this time confined him ; lot him then multiply according to his nature, and not only would all our fruit and field crops go down in quantity before him (tobacco, very doubtfully excepted), but the shade upon which depends our water supply would be more seriously threatened by this creature than it now is by forest fires or the woodman's axe. The water supply of many districts, too, might well suffer extreme pollution by dying hosts of caterpillars. In brief, every interest that our country owns, whether artistic, recreative, or economic, is to-day most seriously threatened. Abandoning reliance upon mere individual effort, Massachusetts, having opened in 1890 an official contest with the moth, began in 1392 in dead earnest to resist the plague, "in the name of the commonwealth." By this time the caterpillar had spread over 220 square miles of territory (including much wild land), with the ocean at the east, Boston at the south, Waltham and historic'Lexington westerly, and Beverly at the north. The State first patiently And hopefully tried that obvious device for combating the caterpillar, the arsenic spray. By this agent the tentcaterpillar and canker-worm, if douched in time, are kept down readily enough. "Fighting the canker-worm with the poison spray is just fan, and no loss to speak of," as a market gardener once remarked to the writer. But when the spray was tried upon the "gipsy," it did not, in the long run, harm him greatly. Every effort was made to discover why, even to the analysis of the creature's assimilative apparatus. At last it was demonstrated that, though the gipsycaterpillar might not actually fatten, like a Styrian peasant, upon arsenic, heat any rate resisted its ordinary effects. A fullgrown caterpillar of this species, science now tells us, will gulp down without harm fully twelve times as much arsenic as a robust man of the same weight could possibly withstand ! And so the ordinary arsenic spray, while effective to some extent upon very young gipsy-caterpillars, was abandoned as a mainstay. Caterpillars, pupee, moths, and eggs could at least be Killed by hand, and while the killing went on the State Board of Agriculture, under whose direction the caterpillar warfare was soon placed, tried method after method for hastening extermination by some short cut. It was hoped to prevent, the fertilisation of the eggs through trapping and killing male moths in quantity. The female gipsy moth, be it known, though she has well-extended wings, has practically lost (doubtless because of overweighting with eggs) all power of flight. But for this fact the extermination or permanent restriction of her kind would doubtless be deemed hopeless. Though the female moves only by a crawl, the male is a swift erratic flier. By the diffusion, it is thought, of. a subtle perfume, the female gipsy moth makes her presence known to the male from a distance, under favourable conditions, of half a mile. Traps baited with living female moths were set by the agents of the Board. These caught some ten thousand males, and slightly reduced the fertility of the eggs of the neighbourhood where the traps were set, but as a mainstay in extermination, mothtrappins; also failed. Then came the question whether extremes of climatic heat and cold, or deluges of weather dampness, or brief seasons of food scarcity, might not kill the gipsy creature. But the results of careful experimenting along the suggested lines were not encouraging. A gipsycaterpillar, it was found, when young, will bear cold extremely well; thus under nature he is assured protection in the chilly season of his hatching. When older, though preferring shade, he endures heat stoically ; co in the summer season of his maturity the fierce New England sun does not " smite him by day." As to damp, it is conclusively proved that a well-grown gipsy-caterpillar can stay alive immersed in cool, fresh water for about three days; and greedy as the creature is, he will yet when young live, if he must, at least four days without a particle of food. When somewhat older, nine days of starvation does not kill him ; and it is on record that in Europe a gipsycaterpillar has been known to starve nearly a month'without perceptible injury. And the vitality of the eggs is quite quite appalling. Though the gipsy-moth lays her eggs under shelter when she cap, I have myeelf many times seen them in Massachusetts forests stuck upon the smooth trunks of leafless white birches, there to bear delugings of cold rain and the sharp scourginga of the winter winds, and even close enclosure in glare ice, only to evolve next spring into swarming hosts of lusty caterpillars. These eggs, mixed and covered as they are with clotted down, like bunched asbestos fibre, are also sturdy against heat. No light woods fire skimming off perished leaves and twigs, and ! gingerly licking the outer bark of shrubbery j and trees, can kill these eggs in quantity, Even a stronger fire leaves many unhurt. To kill, not scotch, the eggs of gipsy-moths, the Board of Agriculture applied by a hose the intense flame of vaporised petroleum waste. Under the fearful fire concentrated upon them the egga gave way, signalling their death by torpedo-like explosions. Even thus, places of egg-deposit were found which the hose flames could not effectively reach. In the rough stone walla which characterise the ridgy districts about Boston, though the more exposed eggs were incinerated in the petroleum jet, those which were deposited under the lower stones of the walla remained alive, even when the sheltering stones themselves were cracked into fttfSwnti its the awful htafc