While glyphosate isn’t sprayed directly onto grapes in vineyards (it would kill the vines), it’s often used to spray the ground on either side of the grape vines. Moms Across America reported: 
“This results in a 2-to 4- foot strip of Roundup sprayed the soil with grapevines in the middle. According to Dr. Don Huber at a talk given at the Acres USA farm conference in December of 2011, the vine stems are inevitably sprayed in this process and the Roundup is likely absorbed through the roots and bark of the vines from where it is translocated into the leaves and grapes.”
As for how the organic wines became contaminated, it’s likely that the glyphosate drifted over onto the organic and biodynamic vineyards from conventional vineyards nearby.
It’s also possible that the contamination is the result of glyphosate that’s left in the soil after a conventional farm converted to organic; the chemical may remain in the soil for more than 20 years. 
Read more at healthy-holistic-living.com