resource conservation, ecosystem health, sustainability - Since I can't rotate my asparagus and alpine strawberries, how can I prevent pest infestations?

Perennial plantings require a different strategy for pest management.

One such strategy is the use of aromatic pest confusers. This is an edible forest gardening (permaculture) term for plants that have an aroma that masks the aroma of the plants around it. For example, agastache (anise hyssop) planted around asparagus makes it more difficult for pests to find it.

Jacke and Toensmeier, in Edible Forest Gardens Volume 2 list a number of aromatic pest confusers. Included in the list are anise hyssop, horseradish, bee balm and mountain mint.

Prevention is the best way, and another preventive measure is to encourage beneficial insects that eat garden pests. Praying mantis, ladybug nymphs, and some wasps take care of garden pests. They just need a safe place to live. That is why I don't use poisons. Poisons are broad-spectrum. They are designed to kill insects, the helpful and the problematic. They kill monarch butterflies as well as cabbage loopers.

Another strategy, once pests arrive, is the use of diatomaceous earth, also called DE. It is a powder, and is composed of the tiny skeletons of living organisms called diatoms. These diatoms make their skeletons out of calcium compounds, and they have many tiny spines on them. These spines tear the soft tissues of insect pests, killing them. Soft-bodied pests, like slugs, are especially susceptible.

Be careful handling DE. It does the same thing to our soft tissues (eyes, nasal passages) as it does to insects' soft tissues. Wear eye coverings, pay attention to which way the wind is blowing.

Insecticidal soaps are something you could try, should an infestation appear.

An ancient method that I use for asparagus beetles is hand-picking. It is a character-building chore. That is my code phrase for something that is good to do, and is boring, and you can't make it go any faster, and you have to do it every day for it to make a difference. But it is effective, it leaves no residue, and gives one an excuse to stand outside in the garden for a while without having to weed.