photo 1) what is the light green plant hugging my garlic? is there any harm in letting it stay low around the garlic, might it help hold moisture in soil? photo 2) is garlic too dry? why the light color on leaves? mineral deficiency? photo 3) is this a harlequin cabbage beetle? Thank you.
The light green weed in between your garlic is chickweed. It is not considered to have any benefit as a cover crop and may become more of a problem as it spreads by seeds. https://extension.umd.edu/hgic/common-chickweed More concerning is the prickly weed shown in your second photo, which is Canada thistle. This is a perennial weed that develops an extensive root system and it is difficult to remove. It can be in competition with your garlic and other desired crops. Here is information about Canada thistle and how to control it: https://extension.umd.edu/hgic/problems/canada-thistle
You garlic plants look like they are suffering from environmental stress. There are diseases (white rot) and insect pests that can be problematic in garlic production. Are you a commercial grower or is this a garden for home production? If you're a commercial grower, we recommend that you contact your Frederick County Extension Agent, Matt Morris, for help with your crop. His phone number and email can be found here: https://agnrfacultystaff.umd.edu/mjmorris
In your last photo, yes, that is a harlequin bug. Options for prevention/control of these insects are listed here: https://extension.umd.edu/hgic/harlequin-bug-vegetables