neem oil based spray and diatomaceous earth ring around the base

knockout roses buses are likes weeds, nothing is going to kill them. try seven spray works for most things

I’ve used soap and water

I bought. Nee tree mini rose from HD recently. The old flowers faded but the new ones are much smaller. Is it the heat or not enough water? I water it twice a day until excess water come off from the bottom.

Monterey bt spray works well

OP here. Thanks for the advice!
I bought too much castile soap when it was on sale, so I'll probably try that first.

Don't worry, your rose bushes will recover but next year you should try to kill off the sawflies before they causes too much damage.

My knockout roses get eaten by sawflies every Spring. I've failed at killing them by hand -- there are too many of them. What works for me is spraying the bottoms of the leaves with Serenade or Monterey (contains Spinosad). Dilute it with water and use garden sprayer.

https://www.amazon.com/gp/product/B000E28UQU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B002BP12LI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.com/Serenade-Garden-Disease-Control-Concentrate/dp/B000FOKXBW/ref=sr_1_5?crid=2S5XORPGFVJ3Q&dchild=1&keywords=serenade+garden+disease+control&qid=1621023577&sprefix=serenade%2Caps%2C159&sr=8-5

This year my roses got hit by aphids before any sawflies showed up so I sprayed them twice with a mix of water and Dr. Bronner’s Castile Liquid Soap. That killed off the aphids and the sawflies never appeared. Maybe it killed them too? My rose bushes look great!

Anonymous wrote:OP here. It was sawflies. I saw them, but I didn't know what they were until I looked them up just now. The damage is pretty extensive. Most of the leaves are lacy remnants now. The rose bushes seem to be surviving for now.

When new leaves grow, squish them when you notice the holes.

OP here. It was sawflies. I saw them, but I didn't know what they were until I looked them up just now. The damage is pretty extensive. Most of the leaves are lacy remnants now. The rose bushes seem to be surviving for now.

Sawflies (the caterpillars eat the leaves) but you don’t need to spray. For one thing, they eat the new growth - they’re basically gone and will reappear when the roses start growing again after this first bloom is over. For another, you’ll kill all the helpful things that eat sawflies.

What do the holes look like? Regular circles, randomly shaped?

What spray should I use for knockout roses with holes in the leaves? What causes this? Thanks!