How do I safely kill giant grubs without killing my flowers?

I could be wrong, you'll need to look this up to make sure, but you could try diatomaceous earth. But research that first to make sure.

Sevin didn’t work? I would ask my County Extension Office what these grubs turn into, so maybe you can stop them when they’re reproducing.

For now, I would go to a Ranch & Farm supply store & buy a bag of Food Grade Diatomaceous Earth.

It kills insects by grinding through their exoskeletons when they walk through it. They don’t eat it.

Since you’re going t be getting a 25 lb bag for the cost of 16 Oz of Sevin, put on latex or rubber gloves & scoop out enough to make little rings around the base of your plants.

Of course rain will wash it away, so it will need to be re-done.

DE is non-toxic, so you don’t have to worry about pets.

Thank you so much, I can't wait to try it and see if it helps. I thought I might have to just dig up my Lantana's all together just to be rid of the nasty little creatures.

Hi Michelle, try this out, Earth-friendly beneficial nematodes seek out and kill grubs and other soil-inhabiting insects. They come on a sponge (invisible to naked eye) that you soak in water, put in a sprayer and spray your dirt or lawn. They will multiply over time and continue to kill grubs. It's natural and chemical free!

https://www.amazon.ca/Nema-Globe-4003603-Nematodes-Grub-Refrigeration/dp/B0741F8Q8F/ref=sr_1_3?gclid=Cj0KCQiA4NTxBRDxARIsAHyp6gAN5wnKraj1werHLRcJcxQd0_cC-XpQOHvQB7Gr92OKQb_SGo1jyzAaAu2YEALw_wcB&hvadid=208343092310&hvdev=c&hvlocphy=9001388&hvnetw=g&hvpos=1t2&hvqmt=b&hvrand=17305139187317723777&hvtargid=aud-854548931220%3Akwd-297218800793&hydadcr=23314_10093173&keywords=beneficial+nematodes&qid=1580589533&smid=A3DWYIK6Y9EEQB&sr=8-3

Hello Michelle,

If you can catch, place in a jar with a lid and vents, and take it along to a garden centre for identification and remedy, or look up a garden book on pests.... Hope you get it sorted soon.

Milky spore, kills grubs!!!!!!

Here's a post that might help - https://www.almanac.com/pest/japanese-beetles