If the leaves should happen to shade the fruit, not only during the ripening process but at any time after the stoning period, they should be gently turned aside, for, in order that the fruit may acquire good colour and flavour, it should be freely exposed to light and air when ripening; it will bear the direct rays of the sun, even if they should rise to loo°, but nectarines are much more liable to damage than peaches.
Great care is given to the cultivation, and damp atmospheric conditions are desirable during the ripening stages.
The disease is due to poisoning by micro-organisms produced by deteriorated maize, and can be combated by care in ripening, drying and storing the maize.
More indirect methods, such as the grafting of less resistant scions on more vigorous stocks, of raising special late or early varieties by crossing or selection, and so on, have also met with success; but it must be understood that resistant in such cases usually means that some peculiarity of quick growth, early ripening or other life-feature in the plant is for the time being taken advantage of.
This result is partly due to their period of accumulation and growth extending even months after the period of collection by the ripening cereals has terminated, and at the season when nitrification within the soil is most active, and the accumulation of nitrates in it is the greatest.