From Joseph Moore
West Chester July 16. 1792.
Sect: 1d. Last fall was first Observed by us, the Oldest men do not recollect seeing any before. Yet We believe they done some Injury the year before, but for want of Information the Fly was not discovered to be the cause.
Sect: 2d. They were first Observed in the egg last October, in which state they1 continued till April, when they hatched and came out Flys, since we have had two, If not three Generations, nor do they ever appear, in any Other state. And the eggs diposited in April appear to do most Injury.
Sect 3. All kinds of wheat suffered, but having no spelts, I have had no Opportunity to know their effect on them. They do not Injure the roots, Flowers, nor leaves, the Mischief is done to the stock only.
They deposit their eggs like a Locust by stinging through the leaf, which when first layed, are about the size of a Flyblow, and white. They afterward grow larger and turn of a brown colour. I cannot Observe that they draw any nourishment from the stock, yet by presure distroy it.
Sect 4th. Spring wheat most Injured, rye not much. Barley, Buckwheat Oats, and Indian corn, not any. Nor can I observe that they Affect any Kind of Tree, shrub, Fruit or Flower, nor any Kind of grass.
Sect 5th and 6. Their depredations do not appear to be confined to any Particular soil, as light, or heavy, high, or low, But good ground, and well manured, have produced Midling crops, yet none with us have entirely Escaped without Injury.
Sect 7th. I cannot Ascertain the extent of country which they move over in one year. But they do not appear to be more than Twenty miles West of this place. Intelligent persons from Lancaster County Inform me that they have not reached them.
Sect 8th. Deposited in the young plant, they certainly bear the cold of our winter. Nor do they appear to be food for any Animal, Bird or Insect.
Sect 9th A Farmer who rolled a part of his field in Autumn Informed me that it produced more, but could not Ascertain why. Query. Could it be from breaking their Tender Eggs.
Our crops are likewise much Injured by Mildew which some writers erroneously Ascribe to Lightening Others an East wind, Fog, &c. But the true cause is an Insect. They are very numurous, and lay their eggs on the leaves and every other part of the plant. They lay a great many in a few minutes, which either corrode the plant or hatch and feed on it, which destroy or obstruct the Juices before the grain is come to perfection. The wheat that is late ripening (be that from what cause it may) is most Injured by this Insect. My bearded wheat suffered little. But the Other was much Injured. I first Observed them the Twelvth of June, they continued But five or six day, nor did the Mischief appear for several days after. If the above Observations should lead to any mode of preserving so Valuable, and so necessary an Article of our food and Commerce from the depredations of Either of these Insects it will be a secret satisfaction To Your Fr’d & Huml Servt
The largest Are the size when begining to lay the next those which have lay’d their eggs and on the decline.2
The smallest were hatched in the Phial.
RC (DLC); addressed: “Thomas Jefferson Esqr Secretary of State.”
Joseph Moore (ca. 1758–99), recently relocated from his native Goshen in Chester County, Pennsylvania, was a physician who had studied medicine in Philadelphia without taking the degree (J. Smith Futhey and Gilbert Cope, History of Chester County, Pennsylvania, with Genealogical and Biographical Sketches [Philadelphia, 1881], 665). The questions … with regard to the Hessian Fly are printed under 17 Apr. 1792.
1. Word expanded from “the” here and in 10 other places in manuscript.
2. Moore wrote this sentence and what follows on a separate sheet.