But in drill’d Wheat, where the Plants stand in a regular Order, the Sun-beams are more duly distributed to all Parts of the Plants in the Ranks; for which Way soever the Rows are directed, if they be strait, the Rays must, some time of the Day, fall on the Intervals, and be reflected by the Ground, whence the lower Parts of the Wheat-stalks must receive the greater Share of Heat, being nearest to the Point of Incidence, having no Weeds to shadow them.
As to that Cause of the Blight, viz. the Wheat’s dying before the full Time of its Pregnancy be accomplish’d; the Hoe removes all the Objections against planting early, and then it will blossom the earlier: And it has visibly kept Wheat green a whole Week longer, than unho’d Wheat adjoining to it, planted the same Day.
The Antients were perfect Masters of the Vine-Husbandry, which seems to have so engross’d their rural Studies, that it did not allow them so much Reflection, as to apply the Use of those Methods to the Increase of Bread, which they had discover’d to be most beneficial for the Increase of Wine. One Method was, to hoe the Vines after they had blossom’d, in order to fill the Fruit, as in Columella, Lib. iv. Cap. 28. Convenit tum crebris Fossionibus implere: nam fit ulterior Pulverationibus. And if what Palladius says, Tit. ix. be true of the Sarritions and Sarculations in the Month of January, and that if Beans do twice undergo that scratching Operation, they will produce much Fruit, and so large as to fill the Bushel almost as full when shal’d as unshal’d.
Faba, si bis sarculetur, proficiet, & multum Fructum & maximum afferet, ut ad Mensuram Modii complendi fresa propemodum sicut Integra respondeat.
This is to be done when Beans are Four Fingers high, and Corn when it has Four or Five Leaves to a Plant; even then the Harrowing-work, tho’ it tore up some of the Plants, yet it was observ’d to do Good against the Blight.
Si siccas Segetes sarculaveris, aliquid contra Rubiginem præstitisti, maxime si Ordeum siccum sarrietur.
When the Antients observ’d this, ’tis a Wonder they did not plant their Corn so as to be capable of receiving this Benefit in Perfection. They might have imagin’d, that what was effectual against the Blight, when the Corn was in Grass, must, in all Probability, be much more effectual when in Ear.
But the most general Blight that happens to Wheat in cold Climates, is caused by Insects, which (some think) are brought in the Air by an East Wind accompanied with Moisture, a little before the Grain is filling with that milky Juice, which afterwards hardens into Flour. These Insects deposit their Eggs within the outer Skin (or Rind) of the Stalks; and when the young ones are hatched, they feed on the Parenchyma, and eat off many of the Vessels which should make and convey this Juice; and then the Grain will be more or less thin, in Proportion to the Number of Vessels eaten, and as the Insects happen to come earlier or later; for sometimes they come so late, that the Grain is sufficiently fill’d with the said milky Juice before the Vessels are eaten; and then, tho’ the Straw appear thro’ a Microscope to have its Vessels very much eaten and torn, and to be full of black Spots (which Spots are nothing else but the Excrements of those young Insects), yet the Grain is plump, and not blighted, there being an Observation, That the early sown Wheat generally escapes this Blight. And it has been seen, where one Part of a Field is sown earlier than the other Part, without any other Difference than the Time of sowing, that the Grain of the latest sown has been much blighted, and the Grain of the earlier has escaped the Blight, tho’ the Straw of both were equally eaten by the Insects. Hence it may be inferr’d, that the Milk in the one had receiv’d all the Nourishment necessary to its due Consistence, before the Vessels were destroy’d; but, in the other, the Vessels, which should have continued the Supply of Nourishment for thickening the Milk, being spoil’d before they have finish’d that Office, it remains too thin; and then the Grain, when it hardeneth, shrinks up, and is blighted; yet the Grain of one and the other are equally plump until they become hard: The Difference therefore is only in the Thickness of the Milk, that in the blighted being more watery than the other.
The chief Argument to prove, that these Insects are brought by an East Wind, is, that the Wheat on the East Sides of Hedges are much blighted, when that on the West Sides is not hurt: And as to the Objection, that they are bred in the Earth, and crawl thence up the Stalks of the Wheat, because some Land is much more subject to produce blighted Wheat than other Land is; perhaps this Difference may be chiefly owing to the different Situation of those Lands, as they are opposed to the East, or to the West.
Another Cause why some Wheat is more blighted than other Wheat on the same Land, is, the different Condition in which the Insects find it; for the Rind of that which is very strong and flourishing[157] is soft and tender; into this they can easily penetrate to lay their Eggs; but the Wheat that is poor and yellow, has an hard tough skin (or Rind), into which the Insects are not able to bore for the Intromission of their Eggs, and therefore can do it no Mischief. It would be in vain to advise to prevent the Blight, by striving to make the Wheat poor; for tho’ Poverty may preserve Wheat from this Blight, as well as it does People from the Gout, yet that is a Remedy which few take willingly against either of these Diseases: But this, I think, might be possible to remedy it, if we could, from the strongest Wheat, take away so much Nourishment as to turn its Colour[158] a little yellowish just before the Insects come[159] which I suppose to be in June, after the Ear is out, or at least fully formed.