Honeydew on leaves, unknown source

[3rdMaestro]

This one has me scratching my head a bit. On several of my orchids, I occasionally find little drops of sticky, clear liquid (I think its called honeydew?) But it's only on new growth, and I really can't find any evidence of insect infestation. The droplets are also limited only to new growths. Any ideas what might be causing this? Could some kind of infection do this? The orchids that have it seem quite healthy otherwise.

[Ray]

I have generally seen two reasons for the appearance of “honeydew”: deposited by insects or the plant is quite healthy and is merely exuding some apparently excess sugars.

With your description, I’d vote for the latter.

[camille1585]

What kind of orchid is it? 'Happy sap' (as some forum members would call it) is relatively common on new growths of Cattleya and Catasetum for example. It can also be produced for something called extrafloral nectaries, and are common on buds and new growths of many genera across the plant kingdom. The evolutionary purpose of these is thought to be a sort of indirect protection, with the sweet nectar attracting beneficial insects that would then keep the plant safe from pests.

[3rdMaestro]

Good call Camille. They are cattleyas and my one catasetum. Although I noticed a little bit on the newest leaf of a super vigorous NoID phal too, about a week ago.

[DeaC]

Yes...happy sap. Your culture has the plants approval!

[My Green Pets]

Yep and there can be a lot of it!! If you keep your plants outside in the summer, you might find ants, bees, and wasps cleaning it off for you.