What is attacking my bushes
The first photo is an insect attacking your yews:
Cottony camellia scale also called cottony taxus scale (Pulvinaria floccifera) is showing up in landscapes in many parts of Maryland this year. For this scale, you can treat your plants in June with horticultural oil to help smother the more vulnerable juvenile insects when they first hatch (called "crawlers") and use a slightly more concentrated "dormant oil" to manage overwintering scale in the dormant season (when leaves have fallen from deciduous trees). The product label will guide you as to the dilution (unless it's a ready-to-spray product) and how often to re-apply it. Thorough coverage of all plant surfaces, including undersides of the leaves, is important for effectiveness.
Beneficial insects that prey on scales tend to arrive to control their numbers naturally, but the population looks large.
Your yews look large and spraying may be difficult or impractical because you have to target the undersides of the leaves. So another option would be is to hire a landscape professional to apply a treatment for you. Heavily infested sections of the plants can be pruned. Dispose of the cuttings.
The second photo is sapsucker damage and is totally unrelated to the scale.