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Diatomaceous earth and aphid control

Posted by albaby 10B (My Page) on
Fri, Jan 14, 11 at 21:05

I've written before of my (thus far) futile efforts to control the aphids that are plaguing my poor eggplants...and at Lou's suggestion, I picked up some diatomaceous earth and a handy duster. So for the past week and a half, I've periodically given the eggplants a good shot of DE - making sure to get into the crevasses and under the leaves.

Unfortunately, there's been no real effect. In fact, since I stopped my efforts at spraying with soap solution in favor of dusting, the little critters have propagated like....well, like wildly propagating insects, I guess. The blooms are so completely covered with aphids you cannot see the underlying petals, while the undersides of some leaves are so thickly coated that you could write your name with your finger, scraping them off. Ugh!

So I wonder...am I perhaps doing something wrong? I've got food-grade DE, dusting every 2-3 days, shooting enough out to make my plants look like a powdered donut (though not opaquely white). Or does it just take this long to bring the aphids under control?

Albaby


Follow-Up Postings:

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RE: Diatomaceous earth and aphid control

Albaby,
That sounds exactly how my plants looked, (like frosted donuts) then after what seemed like forever the aphid outbreak did decline. I think it is because I waited too long before I saw them and dusted, they were thick and settled in, but now I look and there's none on the plants.
The aphids didn't die from the cold as these plants are in my heated greenhouse and I checked the plants a couple days ago and again today. Try flicking the plants with your finger and see if some of the aphids are now dead and fall off.

I don't know what else to say as the DE worked for me.
Lou


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RE: Diatomaceous earth and aphid control

Oh, they're alive alright. If you grab some and squish them, they're....(how can I say this without it being too gross)...."firm and moist." Ugh.

They have a really good foothold, so that might be the problem. I'm going to take time over this weekend to just manually scrape off as many as I can, and thin their numbers - then dust 'em again. Maybe that'll slow them down.

I just wanted to make sure I was doing this correctly, though - sounds like I'm getting roughly the right amount on there, just needs time to take out that many aphids. Thanks!

Albaby


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RE: Diatomaceous earth and aphid control

Albaby,
The reason it takes time is the DE to them is like what broken glass shards is to us. The DE has sharp edges causing cuts on their bodies and they lose juices, dry out and die. At least that is how I understand it works on them. So yes it does take time but it wipes out the colony as newly hatched aphids get sliced up immediately on hatching and don't live long enough to lay eggs, thereby interrupting the life cycle.
I was also squishing them at first, the dang things were everywhere, and my fingers got sticky with them.

Some people put onions and garlic in a blender, puree that and spray it on the affected plants, but I find that just makes them leave and find another plant. I want them dead.

Lou


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RE: Diatomaceous earth and aphid control

The problem with using DE on aphids is it takes too long to work. I'd try some neem oil or this mixture: 1 tbsp Murphy's Oil Soap, 1 Tbsp baking soda to 1 gallon of water. Spray in the evening or early morning, as with any oil spray. For some reason, either the oil of the baking soda dries them up and kills them.


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RE:Diatomaceous earth and aphid control

dirtygardener,
The oil works by coating their body with oil so they can't breathe, the baking soda holds the oil in place. I've found using that method I almost had to have the plants dripping with oil to kill them.
Six of one, half dozen of the other, whatever works for you.

Some people use a strong hose spray to wash them off the affected plant but I find that just spreads them around to the other plants.

If ants are herding the aphids then tanglefoot works.

Everybody's garden layout is different so the different methods have to be used accordingly. No one way fits all.

Lou


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RE: Diatomaceous earth and aphid control

I tried Neem oil first, then a Murphy's mixture (no baking soda, though). Neither seemed to slow them down. These aphids are on the eggplants that I planted in September, and a strong hosing would probably knock the plants over. The only thing that's seemed to work is squishing the buggers, but there's too much plant for me to do that as a form of permanent control.

The plants actually seem quite robust, despite the aphids - so I don't mind giving it a little time. The aphids kill the blooms almost immediately, though, so I get no produce. I'm willing to try the DE for a while, see if it works - and if not, I'll just tear out the plants and start over when I do my spring plant. I hate to do that with healthy plants, but if I can't get the aphids under control, it will really be my only option.

Albaby


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RE: Diatomaceous earth and aphid control

I'm locked in battle with aphids now too with my broccoli, collards, and eggplant. I have found that praying them off really just knocks them off only to have them climb back on. I have been trying to control them by harvesting the snot out of the collards and then spraying everything down with safer's soap with a healthy dose of BT in the mix. I've seen a few green cats when washing the collards. Death to the bugs!

Next spraying will be with NEEM and Spinosid. I have been alternating. It all seems to work but when there are so many of the little bastages it's hard to win the fight.


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RE: Diatomaceous earth and aphid control

  • Posted by whgille Oakland FL Zone 9B (My Page) on
    Sun, Jan 16, 11 at 12:38

Albaby, the only thing that worked for me when I had problems with aphids in eggplants is a pyrethrum spray, I use pyola and only when necessary early morning.

Captturbo, I don't spray anything when the weather is cold, the trick not to get aphids in the brassica crops is to pick them early, I just grab garbage bags full of greens and give them away to happy people, they all appreciate instead of me waiting for the crops to get buggy. Even my dogs eat a cabbage a day (keeps the Dr away) lol

Silvia

Here is a link that might be useful: aphids


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RE: Diatomaceous earth and aphid control

If worse comes to worse, I pull out the trusty Sevin 5% dust. I'm not losing my veggies just to stay organic.


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RE: Diatomaceous earth and aphid control

Thanks so much to everyone for the continued advice. The pyrethrum is a new one to me - if the DE doesn't work, I'll move on to that.

I had considered the Sevin dust, in extremis - it's been mentioned several times as the Holy Hand Grenade of critter control in various threads. Honestly, one reason I hadn't gone there is that the label does not identify aphids among the five or six dozen insects that the dust controls, so I figured that the little buggers weren't affected by it. The other is my daughter, just turned three today. While I'm reasonably confident I can keep her out of the garden until the dusts and sprays settle, I'm still a bit reluctant to use anything too potent. I'm not losing my veggies just to stay organic, but I'm not risking exposing my daughter to something nasty just for veggies.

Albaby


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RE: Diatomaceous earth and aphid control

DE DOES take a long time. I use tin foil when I straight seed, the foil reflects the sunlight to the undersides of the plants which discourages them...Have you given them a good blast with the hose? That will remove most of them I use Sevin...I agree with DirtyGardener. I'm not going to put all that time into growing, collecting seed, propagation, etc. to give them to aphids~ewwww. I have no daughter, but we used to powder the dogs with Sevin for flea control. Never lost a dog to anything other than old age and one gator.

They'll do the same to your southern peas btw...


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RE: Diatomaceous earth and aphid control

unrelated to aphids, but I used DE for roach control after a sudden infestation in the kitchen. I felt like it took forever to work. Every roach scittering across the counter at night made me want to call an exterminator. But I hated the idea of the chemicals, and our house is really open to the outdoors coming in, so I figured the chemicals couldn't control my whole neighborhood. After two or three months of really diligent dusting of corners and behind the oven, it finally worked. For those using with roaches, I saw that it was working when roach poop stopped being pellets, but was instead little smears. At that point, all I had left was half-dead roaches with intestinal problems.

Now, I sprinkle every so often just to maintain control.


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RE: Diatomaceous earth and aphid control

FWIW, aphid infestations on my plants always attract lacewings & ladybugs & I soon see their larvae feeding on the pests & soon all that's left are the empty aphid skins & lacewing/ladybug pupae - I'm wondering whether the DE might've killed helpful predator larvae?

Also, sorry if I missed it, but did you try washing the aphids off w/ water? A strong spray will usually dislodge most of them....


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RE: Diatomaceous earth and aphid control

I suspended my spraying program a week ago when I started seeing lady bugs on my eggplants. I don't know if they can keep up with the aphids but I'm willing to give them a shot at it.


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