Tachinid Fly Problems

[rbtbob]

Hello, this is my first post although I have been reading for a couple of years now. In an effort to stop the paper wasps, I built a screen house over an 5 x 8 patch of tropical milkweed plants and brought in cats from other patches attempting to raise and release as many butterflies as I could this season. To my great dismay, many turned out to be infected by Tachinid flies. I still have quite a few cats outside and am trying to bring in to a terrarium only the healthiest looking ones to pupate. Looking at the cats, I think that I am spotting wounds on the backs of some ( is this possibly a correct method? ) and generally bringing in only the fattest and best looking of the last big hatch. I also under-estimated how many plants it would take to feed the cats, as the fall migration here was much larger than I expected. So, how do I prevent Tachinid fly infestation and gauge how many cats per plant to allow for. I have a small green house that I over-winter tropical milkweed in. Any other advice for attempting to raise and release monarchs here in north Alabama would be greatly appreciated.

[Mona Miller]

I was trying to do some research on this and it looks like 12-20 medium sized leaves or a 2 ft. plant, but some seem to eat more than others and we end up discarding leaves that are older if plants are cut. There is a lot of info on the forum about flies. Fall is a very bad time for them and older caterpillars 2nd-5th instars are more likely to have an infestation. Depending on the screening in your 5x8, the flies could have been laying on the caterpillars that were molting on the screens.

Just put "flies" in the search upper right.