Honey-dew

Honey-dew, a viscid saccharine exudation which is often found in warm dry weather on the leaves and stems of plants, occurring on both trees and herbaceous plants. It is often, but not always, associated with the presence of Aphides, Coccis, and other insects which feed on the juices of plants, and its flow is ascribed to their punctures; but the rupture of the tissues from any other cause, such as the state of the weather, seems also to produce it, and warm dry weather seems to be necessary for the production in the sap of that superabundance of sugar which is thus thrown off. Aphides themselves exude by certain peculiar organs (see APHIS) drops of a fluid which is called honey-dew, which probably differs considerably from the direct exudation of the plants on which they feed, but mingles with it where they abound. Honey-dew is often so abundant as to fall in drops from one leaf to another on to the ground, sometimes falling from trees even as a copious shower. Different kinds of manna are the dried honey-dew or saccharine exudation of certain plants. See MANNA. But very generally this exudation, as it dries, coats the surface of leaves and branches with a clammy film, to which everything brought by the atmosphere adheres, and on which moulds and other small fungi soon grow, and thus the pores of the plant are clogged and its health is impaired. Gardeners are therefore careful to wash off honey-dew with the syringe. Orange and lemon plantations sometimes suffer great injury from the abundance of honey-dew; and it has proved a cause of very great loss in the coffee-plantations of Ceylon.