Grubs in potatoes

[dcpuller]

Hi,I was wondering what to use next year to kill potato grubs. Dug my potatoes today and had to through 15 nice ones away because of grub damage. I have the big white grubs and this is the first year for a garden since purchasing the house 6 years ago. Dave Schupbach, Southern WI

[rainbowgardener]

The white grubs are larvae of some beetle. You said this was new garden. If it was previously lawn, these are most likely Japanese beetle grubs (could also be May or June beetles). There is also a white grub that is specific to potatoes, the sand chafer, but if potatoes had never grown there before, it is less likely.

Anyway milky spore disease would work against any of these. Over the winter the grubs are deep in the ground and not accessible. Once the soil warms up, they move up closer. In the summer, they emerge as beetles, eat, mate, lay eggs in the soil and start the process over. Milky spore powder can be applied in spring or fall, as long as soil temperature is over 65 degrees. It works against all these grubs, but is not harmful to anything else. The disease multiplies itself in the soil, so it does not need to be reapplied.
https://www.gardensalive.com/article.asp?ai=768&bhcd2=1283605751

There are also beneficial nematodes that work against the grubs.

[gixxerific]

I will attest to the effectiveness of milky spore. At least so far this year it seems to have worked for me. I had a ton of Jap beetles this spring after applying MS they seemed to have moved on to my neighbors yard. He is having issues pretty bad where I have zero.

[garden5]

Welcome to the Helpful Gardener gardening forum !

I'm no potato expert, but [url=https://www.ca.uky.edu/entomology/entfacts/ef304.asp]here[/url] is some good info on potato pests. Hope you have better luck with your future harvests.

[rainbowgardener]

Glad something worked for you gixx, but the milky spore is only effective against the grubs in the ground. It doesn't do anything to the adult beetles.

[garden5]

Yeah, that's what I was thinking, Gix . If you just put it down this spring, you shouldn't notice any difference in the beetle population until next year.

[gixxerific]

True RBG I'm just saying think about this for the future.

[applestar]

If Gixx's timing was good, and Mother Nature's weather was favorable MS might have kept this year's 2nd generation from maturing/emerging.

In my area, the drought might have set MS back quite a bit. I may have to re-apply once the rain comes back.

[garden5]

Might not be a bad idea, Apps. Since you are probably going to let what is there be for quite a few years, you want to make sure you are starting with a good population .