Agriculture Reference
In-Depth Information
high acidity, which plays an important role in the system that prevents bacterial growth.
The pH of honeys may vary from approximately 3.2 to 4.5 (average pH = 3.9), making
it inhospitable for attack by most, but not all, bacteria.
Honey also has its own antibacterial substance in its make-up. Bees add an enzyme
called glucose oxidase to honey, and this enzyme reacts with glucose to produce
hydrogen peroxide and gluconic acid, both of which have an antibacterial effect. This
system is most active in dilute honey and probably helps preserve honey diluted for
brood food use.
Like most products of the hive, honey is essentially a by-product of the all-important
pollination process. The value of honey in the economy of the major honey-producing
nations is far less than the value of pollination, but there is a huge global trade in honey
and many beekeepers can make a very decent living by producing good honey either in
bulk or packaged for sale.
Honeydew
Honeydew is a sugar-rich sticky substance, secreted by aphids and some scale insects
as they feed on plant sap. Because the sap has little protein, the aphids need to take in
large quantities of this high-pressure liquid and, when their mouth-part penetrates the
phloem, the sugary liquid is forced out of the gut's terminal opening at the back end.
Bees and ants feed on this liquid, which drips off the aphids onto the leaves and bark
of the tree. Certain ants actively guard their aphids from predators and, in Germany
where honeydew is highly prized, ant colonies are moved into certain forests for
apicultural purposes. Honeydew is therefore still a plant-derived substance but it also
has the addition of insect enzymes as well as bee enzymes and generally has a broader
spectrum of sugars.
Honeydew is usually very dark in colour, often due to the sooty mould that can form
on it. In times of drought, when aphid and other pests tend to increase in numbers,
honeydew can be a very good crop for the beekeeper, and honeydew from the beech
forests of New Zealand is a major export.
