what to put on potato plants?

[sheeshshe]

cucumber beetle or potato bug larvas have taken over my potato plants. I put on DE last night, but this morning they were still alive. What else can I try? There's way too many to pick off. Sad thing is, we've been diligent about picking off the eggs, however we missed a few days, and apparently that is all it took.

[Bobberman]

I shoot garden raid on them since I don't eat the greens and it won't hurt the potatoes. It kills them quick about once a week! put some of the bugs in the blender with water an spray the plants this will also attract preditor insects. Lots of home mixes will work like a few drops of dish detergent in water.

[applestar]

Bobberman, are you talking about Raid House and Garden Bug Killer?

Here is an IMPORTANT excerpt from the label:

GARDEN BUGS: Product is intended for use on ornamental garden plants only. It is not for use on edible crops.

https://www.raidkillsbugs.com/-/media/ra ... mula-7.pdf

Also, detergent is not recommended, particularly not on solanacea. Though I agree that at newly hatched larval/juvenile stages potato beetles can be susceptible to SOAP solution.

With mobile bugs, I tend to hold a container of soapy water under where they are on the plants and drive the bugs to jump off or drop in.

I generally don't use them myself, but I believe this would be better handled with neem or spinosad if spraying. There used to be Bt for potato beetles too, but I don't see them very often now. I wonder why?

[sheeshshe]

I've never seen them as bad as they are this year. I do think I have some neem down in my basement though, once this rain clears out from the storm, I think I'll try that. Do they die on contact? Any idea why the DE didn't work on them? I was really surprised, since when I dusted them, they looked like they were screaming for their lives, and then they were still alive in the morning. Maybe it didn't stay on them long enough before it rained and washed off the DE? does DE have to stay on X amount of hours/days before it dries them out and kills them?

[tomc]

Please try BT Baccilus thurengensis it works well against larval stage potato beetle.

[rainbowgardener]

"Diatomaceous earth may need to be left down anywhere from 1 day to a week or more in order to be effective against an infestation [of insects]. ... for Beetles such as Merchant grain beetles and Darkling beetles [it takes] 7-21 days. .... Note: it is important that you re-apply the DE if any area that you have applied it becomes wet as the product will wash away very easily." https://www.absorbentproductsltd.com/how ... sects.html

I don't use DE as much as I otherwise might, because of the have to re-apply after rain thing. Where I am it rains frequently in the summer.

[sheeshshe]

I have BT and Neem apparently!

[applestar]

But there are different strains of Bt.

Bt var. kurstaki is the one effective for Lepidoptera (butterflies and moths) caterpillars and MOST often referred to as simply Bt.

Bt var. israelensis the species effective against mosquito and fungus gnat larvae, and is quite prevalent now.

Bt var. sandiego -- and I had to look it up it's been so long -- and Bacillus thuringiensis var. tenebrionis are the strains of Bt effective for Colorado potato beetles. But I have heard that they quickly developed resistance to them (some blame over-use after the initial release of sandiego, necessitating development of tenebrionis.)

I think the current recommendation is spinosad, though.

[sheeshshe]

I used the neem. I hope it works! I just only have the regular BT, and it didn't say it would work for potato beetles, so I didn't use it.

[rainbowgardener]

Be a little patient. Neem is not a poison and it also does not kill on contact. The beetles have to ingest it as they eat the leaves and then it disrupts their systems and keeps them from eating or mating. So eventually they die, but not instantly. It can take from 3 days to a couple weeks for them to die.

[sheeshshe]

I guess I"ll have to pick more larvae off each day, bc I can't wait weeks for the neem to kick in! my plants will be demolished by then! but honeslty after an hour of picking, and getting about half a cup of them things, thousands of them! I had to take a break. maybe I can go out there in the morning for a little while. family is in town and we've been out straight!

[sheeshshe]

Been picking them off every day, and I go out today and they're covered in thousands again!

[rainbowgardener]

Wow! I've never seen an infestation like that. It is the colorado potato beetle we are talking about? Here' a nice article about them:

https://www.potatobeetle.org/overview.html


You should read the whole article, but suggestions from this article (and a couple others I looked at) include the importance of rotating crops and not planting your potatoes within 200 feet of where they were the previous year, trap crops, mulching. It says a 3" layer of straw mulch resulted in a 2.5 to 5 fold decrease in the defoliation of the potato plants. There is also trenching (see article), row cover, and vacuuming them off the plants. They note that plants grown with manure are less attractive to the beetles than plants grown with synthetic fertilizers. Lady beetles are predators of the eggs and small larvae. Birds and parasitic wasps also prey on them, so you want to design your garden to attract those (doesn't help right now, but you could be in better shape next year). And hang in there with the hand picking. Once this generation of larva are done, there won't be more for awhile, so it won't last forever!

I looked for trap crops for the potato beetle and all I found was more potatoes. So you want to plant your perimeter with early planted, early maturing varieties, that will be ahead of your main crop. Then the beetles will be attracted to the early plants and you can either flame them or bag the plants with the beetles.

Don't get tempted to use poisons. It notes that these beetles are already resistant to most of them and are extremely good at developing new resistances. If you start spraying poisons, you will just be breeding resistant beetles.

Good luck!!

[jal_ut]

Have you ever used "Bug Spray"?

What you do is hand pick all the beetles you can find, then put them in a blender with some water and liquify them. Now strain and pour the mix into your sprayer and add enough water to cover the area and go spray the plants.

The theory is that you are spreading any disease the critters may have . I also wonder if it isn't sickening to be plastered with the remains of the species? It would be for me I am sure............. I would want to leave the area.

[sheeshshe]

yeah, IDK! my property isn't big enough to move them 200 feet. they're moved just 10 feet over from last year LOL. I think I know what happened. I picked off the leaves and I threw them out of the garden, thinking that was fine, but they crawled back into the garden. I didn't think they could do that being newly hatched, but someone told me they do. so that's what went down they just keep coming!

I guess I need to find an old blender, bc I don't want to blend up bugs in my smoothie blender, eww LOL! BTW, my sprayer is broken. so I was out there with a hand sprayer which only halfway works. looks like I need to head to the store.

[rainbowgardener]

They said mulching really helps. I would seriously do that. Mulching is good for your soil anyway. You can buy one bale of straw and it will be all you need for mulching and browns for your compost pile.

[sheeshshe]

I havent seen any adults lay more eggs, and I am picking picking picking larvaes still. I'm noticing there aren't as many to pick the last day or two, woop! Hopefully I caught them all before they pupate and make more adults and lay more eggs!