Thursday, September 3, 2009

Honeydew on Trees

There are times of the year when cars parked under certain trees get covered with fine droplets of a sticky substance. This is especially noticeable around oaks and tuluptrees in the spring and pecan trees at almost any time. The leaves of sugarberry trees are now covered with this sticky substance, called honeydew. Honeydew is a sugary secretion from chewing or gnawing insects that attack certain trees. The insects derive carbohydrates from the saps of the trees and then secrete the honeydew. There is enough sugar in honeydew that honey bees will collect it and bring it back to the hive. The honeydew is mixed with enzymes in the bee’s honey gut and chemical changes start to occur. If enough of these sugary insect secretions are brought into the hive, a form of honey, which is also called honeydew, is produced.

Click on the photo and you can see the discolored, shiny, sticky leaves of the sugarberry tree. The tree is infested with white flies, the irregular white spots on the leaves. As the white fly consumes the sap of the hackberry tree, it produces the sticky honeydew showing on the leaves. On the left side of the photo is the acorn-size mud bottle nest of the potter wasp, a native paralyzing wasp. Potter wasps capture beetle larvae, spiders, or caterpillars, paralyze them, and place them in the mud cell to serve as food for a potter wasp larva. The potter wasp lays an egg in the cell with the paralyzed provisions and then seals the mud bottle. The developing potter wasp derives nourishment from paralyzed insects or spiders; and the adult wasp derives nourishment from flower nectar, as do honey bees. It is thought that Native Americans based their pottery designs upon the potter wasp nest bottles.


  1. Hello Richard,here in NZ we had a real problem with toxic honeydew that bees collected from a native plant called Tutu, Coriaria arborea,acouple of summers ago.We had had very little rain to wash the honeydew off the foliage, the bees took it back to the hives, the beekeeper who should have known not to take honey off after the end of Dec, sold his honey and promptly poisoned a number of people. This plant is highly lethal to humans and animals, ok for the bees, doesn`t smell or taste any different and there have been deaths over the years. Beekeepers in certain areas of NZ where this plant tends to grow profusely should be aware of the danger.
    The honeydew is produced by a small insect Scolypopa something,a small lace-wing flicky insect that sucks the sap from the Tutu and excretes the sticky honeydew out it`s other end onto the leaves - bees love it.
    All beekeepers who sell or give their honey away, are now meant by law, to have their honey lab tested for this toxin if the honey has been taken off before the end of Dec.

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  4. Ngaio,
    Thank you for the most interesting report. I see that Coriaria arborea is described as "beautiful but deadly." It is good to hear from my New Zealand friend. In the Antipodes, you are ending winter with red maples bringing out honey bees. We are harvesting summer honey in the Delta.