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Insects feed on plant sap by sucking it out of leaves. In general, plant sap contains many sugars, but few proteins. Because proteins are the main nutrients for insects, they need to suck up a large amount of plant juices to get enough protein. At the same time, they take in large amounts of sugar but they don’t use up all of this. As a result, they excrete excess sugar as honeydew from a gland.

As mentioned above, honeydew is a good breeding ground for sooty mold. This forms a black layer on the leaves that looks like a layer of soot (hence its name). Together, they form a sticky layer on the leaf which, in severely affected cases, can suffocate the plant because it causes the plant to receive less light and thus its levels of photosynthesis are impaired.

Apart from sooty mold, honeydew also attracts various insects, such as ants. This is because ants use honeydew as a food source.

Honeydew can be treated by treating the insects that produce honeydew in the crop. Fighting these pests can be done by using natural enemies like CHRYSOcontrol, biological crop protection methods and/or chemical crop protection products. On our page about pests, you can find itemized information for each pest about suitable treatment methods. 

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