As to the ten or a dozen different insects to which the Potato-rot has been attributed, I regard them all as consequences, not causes; attracted to prey on the plant by its sickly, weakly condition, and not really responsible for that condition. If any care for my reasons, let him refer to what I have said of the Wheat-plant and its insect enemies.[1]
There has been much discussion as to the kind of seed to be planted; and I think the result has been a pretty general conviction that it is better to cut the tuber into pieces having two or three eyes each, than to plant it whole, since the whole Potato sends up a superfluity of stalks, with a like effect on the crop to that of putting six or eight kernels of corn in each hill.
Small Potatoes are immature, unripe, and of course should never be planted, since their progeny will be feeble and sickly. Select for seed none but thoroughly ripe Potatoes, and the larger the better.
My own judgment favors planting in drills rather than hills, with ample space for working between them; not less than 30 inches: the seed being dropped about 6 inches apart in the drill. The soil must be deep and mellow, for the Potato suffers from drouth much sooner than Indian Corn or almost any other crop usually grown among us. I believe in covering the seed from 2 to 2-1/2 inches; and I hold to flat or level culture for this as for everything else. Planting on a ridge made by turning two furrows together may be advisable where the land is wet; but then wet land never can be made fit for cultivation, except by underdraining. And I insist upon setting the rows or drills well apart, because I hold that the soil should often be loosened and stirred to a good depth with the subsoil plow; and that this process should be persevered in till the plant is in blossom. Hardly any plant will pay better for persistent cultivation than the Potato.
As to varieties, I will only say that planting the tubers for seed is an unnatural process, which tends and must tend to degeneracy. The new varieties now most prized will certainly run out in the course of twenty or thirty years at furthest, and must be replaced from time to time by still newer, grown from the seed. This creation of new species is, and must be, a slow, expensive process; since not one in a hundred of these varieties possess any value. I don't quite believe in selling--I mean in buying--Potatoes at $1 per pound; but he who originates a really valuable new Potato deserves a recompense for his industry, patience, and good fortune; and I shall be glad to learn that he receives it.