Sticky sap droplets

[brian]

I've noticed that most of my trees seem to have areas of clear, sticky droplets on their leaves.  It only affects maybe 5% of all leaves and seems completely random.  It doesn't seem to match up with where I find mealybugs.  Any idea what this is caused by? This is in a greenhouse.

It looks like water or oil droplets but it feels like dried glue.

[Chas]

It's nothing to worry about! 
This is happen most often with my citrus trees in the spring when the sap really starts to flow.

Have a look here: http://citrus.forumup.org/viewtopic.php?t=7367&highlight=crying&mforum=citrus

[So_Cal_Mike]

Look for soft bodied scale insects.

[brian]

Thanks.  I did check for scale and I occasionally find mealybugs around the stems and underneath leaves these droplets seem to be on the tops of the leaves where I never find scale, and I check often.  Does sap really just seep from the leaves without any damage?

[So_Cal_Mike]

I've never seen that happen on it's own, but I have seen exactly that with soft bodied scale. It will drip down from above and land on the top side of leaves.

[Millet]

brian what you are seeing is known as guttation, and is no problem (in fact it could well mean that your trees have a very good developed root system).  Look up guttation on the internet for a full explanation. - Millet

[So_Cal_Mike]

Millet,

Why do you suppose I've never seen that on my trees here in southern California? Maybe the air is too dry for it to manifest?

Thanks,

-Mike

[So_Cal_Mike]

Doing some (very) quick reading, shouldn't guttation be more water like than sticky and glue like?

[Millet]

So_Cal_Mike, you would certainly think so. - Millet

[Chas]

brian what you are seeing is known as guttation, and is no problem (in fact it could well mean that your trees have a very good developed root system).  Look up guttation on the internet for a full explanation. - Millet

Hmm, so this process is called guttation, good to know and as usual many thanks Millet! 

[brian]

I had never heard of guttation before, thank you.  Because I never see scale on the tops of leaves I am hoping this is the explanation.  My trees are all pushing out new growth or blooming right now so it sounds reasonasble. 

I've never seen this when my trees are outside, I wonder if rain would wash the sap away under normal circumstances and it is just accumulating because mine are indoors for the winter.