Before setting out from home for Hanover to begin the task of clearing a site and constructing the first buildings to house his family and students, Wheelock outlined his plans for the immediate future in a letter to the Trustees in England, dated Lebanon, Connecticut, 29 July 1770:
I am preparing to remove immediately, unless a report very lately come among us, viz. that an army of Worms, [italics added] which have this year invaded several parts of this Land, have so prevail'd as to cut off great part of the crops in yt. Country & threaten them with great scarsity, should be so confirm'd as to convince me I must stay for want of subsistance. (2)
A few days later, August first, this was followed by a comment in a letter to John Wentworth, governor of New Hampshire; 'The melancholly recots of Destruction by worms [italics added] make me fear whether I shall be able to subsist with my mushroming family in the woods the ensuing winter. howevr, I am preparing to remove as fast as I can.' (3) What was the 'army of worms' Wheelock referred to? How could 'worms' prevent or at least delay his departure for his new settlement? Among the 'melancholly' reports Wheelock had received, there probably had been an item in The New-Hampshire Gazette :
Hartford, July 16. For about 10 days past, there has increased and prevailed in this and some of the Towns, such Multitudes of a Kind of Brownish Streaked Worm, as have been very distructive to the Fruits of the Earth. They frequently appear in Swarms as to almost cover the Surface of the Earth in some places, and feed greedily on all kinds of herbs that comes in their way, whether in Gardens or Fields, especially the latter, where they make such a waste among the Grass as threatens a great Diminution if not almost the total Destruction of whole Crops. 'Tis observed that the General Course is to the Westward. And we hear that the same kind of Vermine, do also abound in Distant parts of the Country both North and South. (4)
The most complete account of this episode was assembled by the Reverend Grant Powers (1784-1841), Dartmouth Class of 1810, who was born in Hollis, New Hampshire, and served as minister in his native state and in Connecticut. Powers collected eyewitness accounts of a number of people and compiled the narratives as part of his Historical Sketches . One would be remiss not to give the major portion of Powers's story in full.
In the summer of 1770, this whole section of country was visited by an extraordinary calamity, such a one as this country never experienced before or since, beyond what I shall here specify. It was an army of worms, which extended from Lancaster, N.H., to Northfield, in Massachusetts. They began to appear the latter part of July, 1770, and continued their ravages until September. The inhabitants denominated them the 'Northern Army,' as they seemed to advance from the north- west, and to pass east and south, although I do not learn that they ever passed the high lands between the Connecticut and Merrimack Rivers. They were altogether innumerable for multitude. Dr. Burton, of Thetford, Vt., (5) told me that he had seen whole pastures so covered that he could not put down his finger in a single spot, without placing it upon a worm. He said, he had seen more than ten bushels in a heap. They were unlike any thing which the present generation have ever seen. There was a stripe upon the back like black velvet: on either side a yellow stripe from end to end; and the rest of the body was brown. They were sometimes seen not larger than a pin; but in their maturity, they were as long as a man's finger, and proportionably large in circumference. They appeared to be in great haste except when they halted to devour their food. They filled the houses of the inhabitants, and entered their kneading-troughs, as did the frogs in Egypt. They would go up the side of a house, and over it, in such a compact column, that nothing of boards or shingles could be seen! They did not take hold of the pumpkin-vine, peas, potatoes, or flax; but wheat and corn disappeared before them as by magic. They would climb up the stalks of wheat, eat off the stalk just below the head, and almost as soon as the head had fallen upon the ground, it was devoured. To prevent this, the men would 'draw the rope,' as they termed it; that is, two men would take a rope, one at each end, and pulling from each other until it was nearly straightened, they would then pass through their wheat fields, and brush off the worms from the stalks, and by perpetual action they retarded the destruction of their wheat; but it was doomed, finally, to extinction.
There were fields of corn on the meadows in Haverhill and Newbury standing so thick, large and tall, that in some instances it was difficult to see a man standing more than one rod in the field from the outermost row; but in ten days from the first appearing of the Northern Army, nothing remained of this corn but the bare stalks! Every expedient was resorted to by the inhabitants to protect their fields of corn, but all in vain. In the first place, they dug trenches around their fields, a foot and a half deep, hoping this might prove a defence; but they soon filled the ditch, and the millions that were in the rear went over on the backs of their fellows in the trench, and took possession of the interdicted food.
The inhabitants then adopted another expedient to save those fields yet standing. They cut a trench as before; then took round and smooth sapling sticks, of six or eight inches in diameter, and six or eight feet in length, sharpened them to a point, and with these made holes in the bottom of the ditch, once in two or three feet; and, as their meadows were bottom lands, they experienced no difficulty in extending these holes to two and three feet in depth, below the bottom of the trench. The sides of these holes were made smooth by the bar or lever which made the holes, and as soon as the worm stepped from the precipice, he landed at the bottom and could not ascend again; indeed, he was soon buried alive by his unfortunate fellows, who succeeded him in his downfall. Now, those who made these holes to entrap their invaders, went around their fields, and plunged these pointed levers into the holes filled with worms, and destroyed everyone of them at a single thrust, whether it was a peck or half a bushel. By unremitting effort in this way, some reserved to themselves corn enough for seed the next year.
About the first of September, the worms suddenly disappeared; and where they terminated their earthly career is unknown, for not the carcass of a worm was seen. In just eleven years afterward, in 1781, the same kind of worm appeared again, and the fears of the people were much excited; but they were comparatively few in number, and no one of the kind has ever been seen since.
This visitation, which destroyed the principal grains of that year, was felt severely by all the new settlements; for it not only cut off their bread-stuffs, but it deprived them of the means of making their pork to a great degree, and reduced the quantity of fodder for their cattle. The settlements at Haverhill and Newbury did not feel this calamity quite so much as those infant settlements in the towns north and south of them. They had been longer in their settlements, had some old stock of provisions on hand, and had more means to procure supplies from Charlestown, or by the way of Charlestown. Jonathan Tyler, of Piermont, related to me, that the settlements in that town were left without the means of subsistence from their own farms. His father drew hay on a hand sled upon the ice, from the great Ox Bow in Newbury, to support his cow the following winter. And had it not been for two sources opened for their support, they must have deserted the town. One was the extraordinary crop of pumpkins in Haverhill and Newbury. The corn being cut off, and the pumpkins remaining untouched by the Northern Army, they grew astonishingly, and seemed to cover the whole ground where the corn had stood, and the yield was great. The people of Haverhill and Newbury gave the settlers in Piermont the privilege of carrying away, gratis, as many pumpkins as they would. They went up, made a kind of raft and transported them by water to Piermont. Their raft was a novelty in its kind, and will show us how truly 'necessity is the mother of invention.' They cut them two straight trees from forty to fifty feet in length, and from fifteen to eighteen inches in diameter; and enough of these were generally found, already felled and dry, to answer their purpose. They bored holes near the ends of these trees, and introduced slats to hold them together at each end, in the manner that the long body of a hay-cart is made, only at twice or thrice the distance from each other that the sides of a hay-cart are placed. These two sides were first placed in the water, and then joined together. The pumpkins were then brought from the fields, which were contiguous to the river, and placed in the water, in this oblong square, until it was filled; the pumpkins, being buoyant, would not sink, and could not escape from their pen. Two men in a skiff would then weigh anchor, and tow the raft of tons' weight to Piermont shores, where the freight was landed, and conveyed to the habitations of men!
Another source of support was opened to them in the immense numer of pigeons which Providence sent them immediately upon the disappearance of the Northern Army. Nothing could equal their number, unless it was the worms which had preceded them. The Tylers of Piermont, Daniel, David, and Jonathan, commenced taking pigeons on the meadow, west of Haverhill Corner, and in the space of ten days, they had taken more than four hundred dozen! (6) They carried them to Piermont, and made what is defined, in the Yankee vocabulary, 'a bee,' for picking pigeons; and two or three times a week the people of Haverhill were invited down to Mr. Tyler's to pick pigeons. Those who went had the meat of all they picked, and the Tylers had the feathers; and they made, says Jonathan Tyler, 'four very decent beds of those feathers.' The bodies of those pigeons, when dressed, dried, and preserved for the winter, were very palatable and nutritious, and proved a good substitute for other meats, of which the inhabitants had been despoiled by the Huns and Goths of the north. And we are bound to recognize the Divine Goodness in this providential supply, when the ordinary means of subsistence were cut off. It generally characterizes the Divine Government, when He has tried his people. (7)
Damage to the crops in the summer of 1770 had led to scarcity of food the following winter and spring, forcing Wheelock to import, at great expense, foods from parts of Massachusetts not affected. 'I am forced to support those I have [family, students, laborers] from Northfield, Northampton, etc, and by reason of the drought and worms last year every article of provisions is held at dearest rate,' he wrote in February 1771. (8)
Entomologically, the worms represented the larval or caterpillar stage of a moth Cirphis unipunctata. (9) In very large numbers, moving forward in a solid front while devouring everything that suited their voracious appetites, they resembled an army charging over a broad front. With the end of the larval stage, pupation takes place in the soil, causing a rather sudden disappearance; from the pupa the adult moth emerges.
In a report on insects of Missouri, Charles V. Riley lists a number of army worm infestations occurring in New England after 1770, only one earlier, in 1743. (10) The latter is recorded by the Reverend Thomas Smith in his journal of 27 June and 1 July 1743 concerning an infestation in Maine: 'There are millions of worms, in armies, appearing and threatening to cut off every green thing; people are exceedingly alarmed. July 1. Days of fasting are kept in one place and another, on account of the worms. An exceeding scarce time for hay; it is 7 to 8 a load.' (11) There is, however, an excellent account of an infestation nearly one hundred years earlier (1646), written by none other than the Reverend John Eliot (1604-1690), the 'Apostle to the Indians' and famed translator of the Bible into the language of the Massachusetts Indians, published in 1663:
This yeare  about the end of the 5t month, we had a very strang hand of God vpon vs, yt vpon a suddaine, innumerable armys of Catterpillers filled the Country all over all the English plantations, wch devoured some whole meadows of grasse, & greatly devoured barly, being the most greene & tender corne, eating off all the blades & beards, but left the Corne, only many ears they quite eat of by byting the greene straw asunder below the eare, so yt barly was generally halfe spoyled, likewise they much hurt wheat, by eating the blads off, but wheate had the lesse hurt because it was a litle forwarder then barly, & so harder, & dryer, & they the lesse medled wth it. As for rie, it was so hard and neere ripe yt they touched it not, but above all graines they devoured Sylly oats. And in some places they fell vpon Indian Corne, & quite dvoured it, in other places they touched it not; they would goe crosse highways by 1000. much prayer there was made to God about it, wth fasting in divers places: & the Lord heard, & on a suddaine tooke ym all away againe in all pts of the country, to the wonderment of all men; it was of the Lord for it was done suddainely. (12)
A less detailed account of the same infestation was written by John Winthrop, Governor of the Massachusetts Bay Colony:
Great harm was done in corn (especially wheat and barley) in this month by a caterpillar, like a black worm about an inch and a half long. They eat up first the blades of the stalk, then they eat up the tassels, whereupon the ear withered. It was believed by divers good observers, that they fell in a great thunder shower, for divers yards and other bare places, where not one of them was to be seen an hour before, were presently after the shower almost covered with them, besides grass places where they were not so easily discerned. They did the most harm in the southern parts, as Rhode Island, etc., and in the eastern parts in their Indian corn. In divers places the churches kept a day of humiliation, and presently after the caterpillars vanished away. (13)
Among many reasons to have a fast day or a day of humiliation, 'pests, plagues and prodigies' took, of course, a prominent place. (14) For the 1646 episode, Eliot mentions much prayer with beneficial and prompt results: '. . . the Lord heard, & . . . tooke ym all away.' Winthrop confirms this. Matters were not different almost 125 years later when the Reverend Thomas Clarke in a letter to Eleazar Wheelock, dated 'North Perth County Albany, Septr 29th 1770' told, with a dramatic flourish of similar beneficial effects of fast days:
As to our affairs the Lord has been gracious this season tho' that a dreadfull army of canker worms that cut off most of our corn & meadows in a few days our Elders & I appointed a fast day & yet they went on furiously next Sabath we appointed another day & the Lord graciously heard us for next morning after the fast day they began to die & fight among themselves they marched off from our houses & fields like flocks of sheep. (15)