Tachinid fly, bad or good, and how to control?

Factual Questions
1

I don’t know how many of you are familiar with the Tachinid fly. It’s been giving me a serious headache because it keeps killing my Monarch caterpillars (and the reality of it is even creepier than Jeff Goldbum in The Fly). You can read the long version of my story, but the short version is the Tachinid is a parasitoid fly that injects it’s eggs into the young Monarch caterpillar. The eggs then feed on the living caterpillar and eventually kill it, and emerge and turn into adult flies. The cycle then repeats, over and over again. Yes, the whole thing is creepy (at least to me) and not a lot of fun compared to watching caterpillars turn into chrysalises and then beautiful butterflies. So I googled [Tachinid fly control], and learned that these flies are actually viewed as “beneficial” insects because they also kill bad caterpillars (that eat up my garden vegetables), and the information was all about using tachinids to control other pests insects, instead how to control the tachinid fly itself. I guess seldom is nature black and white. Anyway, all I found was stuff on how the Tachinid fly kills bad pests, but nothing on how to kill the fly itself or get rid of it (and I’m not very fast with chop sticks, aka the Karate Kid).

So what do you think? Does anyone know how to control or get rid of the Tachinid fly, or how to at least protect my (good) caterpillars from it?

And on a philosophical note, do you think the Tachinid fly is bad or good?

2

This subject really hit me this summer. I was growing Narrow Leaf Milk Weed next to my raised bed of tomatoes. The tachinid flies killed every single tomato worm… Great! They also killed every monarch caterpiller. Bad! My thinking for 2019 is to cover the milkweed with mesh to exclude to flies. I’ll have to net wild monarchs and insert them into the milkweed enclosure. Then, I’ll have to release the emerging monarchs. That seems like a lot of trouble; and, I suspect the results will be poor. Has anyone else offered a plan?

3

Don’t grow tomatoes right next to milkweed, next year?

There is no “good” or “bad” in nature. There’s just “benefits this individual human in his own opinion” or not. We like eating tomatoes, so for ex. gardeners love sharing pics of egg- or cocoon-covered hornworms on social media each summer, to much thumbs-up-ing and digital applause.

Or put another way: if we liked eating milkweed, monarch butterflies would be hated like mosquitoes.