What causes a grapevine to actually drip water from its vine?

In the past these grapes have produced nicely and looked great. This year the branches seem to 'snap off ' easily and then drip fluid (looks just like water-not sticky, no smell). The only difference this year is an automatic watering system- are they getting too much water?

Answers:
I don't really know what it is that you are describing, but the links below may help you to determine whether or not you are watering too much.
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