Gerber daisy has had buds about to burst into blooms but all of a sudden the bud disappears. The stem is still there but it appears like something has removed the bud. My yard is fenced with chain-link fencing and I have not seen any evidence of deer. Any ideas?
The loss of bud could be caused by insects, Thrips will 'cut off' blossoms.
Slugs could also cause damage, though I believe you would also see leaf damage in this case.
Inspect the plant for signs of Thrips, and treat the plant with Neem Oil.
Here are some articles with more information.