I would start by asking the horticulturist at your county office of your University of Tennessee USDA Cooperative Extension Service about having a good, reliable soil test done since quite often insect pests are drawn more to plants that are not quite as healthy as they can be. Soil pH and nutrient balance can affect plant health in ways we cannot see and plants growing in a good, healthy soil are better able to ward off these insect pests. You might also want to dig in with these simple soil tests,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
to see what else needs to be done.

Thanks - I will try the soil test. These beds were newly made the prior fall. I know the soil smells ok, and the earthworm population is increasing. It may even be up to 5 per shovel by now, but I'll have to check. The soil was originally a hard clay (fairly new construction, with the top soil carted off to God knows where 3-4 years ago). We tilled in the sod and a bunch of half-rotted shredded leaves and compost. Then topped with newspapers and bark mulch. The pH has been tested and is very close to neutral, but I'll get the other testing done as well. Also, it was a very wet year, so that may also have had an impact.