As far as I've heard, your stomach acid does a pretty good job on lots of things. Stuff that is bad for you (listeria, e.coli, etc) doesn't come from nowhere, it comes from contamination with feces, human typically. And direct sunshine can do a good job killing some of those, as well. If you have an immune disorder, then be more careful. Otherwise, I'm sure that cucumber is cleaner than anything you pick off the grocery store shelf that has been handled by several people, at least.

Are you asking why are there so many milkweed beetles on your other plants at the moment? or if anyone else is having a milkweed beetle problem? or how to get rid of Milkweed beetles?

I think the photo is of milkweed, not dogbane. I was able to identify a patch of dogbane in one of our local parks a few years ago, and the central vein in each leaf was definitely tinted red, not white. The leaf shape is not quite right for swamp milkweed, nor common milkweed, nor orange butterfly milkweed. There are supposed to be around 100 varieties of milkweed, so it is likely some other variety. Please post a photo when it flowers. My guess would be that your milkweed will do just fine competing with the grasses that surround it in the field.

I agree with Martha and Karen. Some natives do well with a pinching or pruning back. For example,joe pye weed will grow shorter and send up more flower heads. To my knowledge Milkweed is not one of them. In fact, I have several purple milkweeds that have never bloomed in three seasons because my hubby mowed them the last two. I grow a lot of Swamp milkweed in all kinds of sites. It is one of the easiest to grow if the conditions are right. It is a wetland plant, so it either requires a lot of water or grow it in shade and very organic soils. You shouldn't need to fertilize it. Again, it is a native and when you fertilize natives, they put a lot of energy into growing taller. I have about fifteen plants I put in this spring at a school garden (along with Sullivant's,tropical and butterfly weed). Of the four milkweeds, they are doing the best and look really healthy. They were grown from seed (started in April). Many of them are blooming right now, which suprised me. I expected them to bloom next year. They are all about 2 - 3 feet tall. My second year plants tend to be taller about four feet. They also only put up one to three shoots from the base after they are a second year. I never have a "bush" like you have there. Even in the wild, I will only see one to three stalks. So, I don't know how that is happening. Is yours from a garden center? Sometimes the cultivars at a garden center are selected for vigorous growth. I have yet to try one of the garden center cultivars. It would be interested in hearing how they differ from wild plants (all of mine are from wild collected seed). In addition, mine tend to decline after a couple years. So, I let the seedlings grow up and take over. Give it another year without pruning. You could always remove some of the side shoots to contain it. Mine never flops over. Again, that may be a function of rapid grown from fertilizer. The beauty of natives is not having to do anything to them! Thank goodness because I certainly neglect my garden at times! By the way there is a fascinating relationship between the different milkweeds and monarchs. We have discussed it in other posts. Some research and our experiences in this forum, lead us to believe that swamp milkweed is the preferential plant for monarchs. Glad to see you have some caterpillars. Cheers, Elisabeth