The white dots on this garlic indicate that the allium leafminer has laid eggs on the plant.
I had a crop failure last year with my garlic, blaming the wet spring. Then I recalled that newer invasive pest called allium leafminer was becoming a problem for onions and garlic. I researched signs of allium leafminers and found images of garlic foliage with lines of white dots. The leaves above in the photo are from my garlic. I’m hoping they have not hatched yet, the foliage was removed, leaving about half the leaves on the plant. The leaves were destroyed, not added to the compost pile. The next step for the organic gardener is treating with spinosad. It can be found as Capt. Jack’s Dead Bug Brew. Penn State recommends adding a surfactant like insecticidal soap, which helps the spinosad stick to the waxy leaves. The spinosad should be applied weekly for at least three weeks. I hope this works and I’ll be picking garlic in July as per usual. I’ll keep everyone posted.