Help me identify this pest (w/ microscope pictures) and suggestion on Pyrethrin
March 31, 2012 7:21 PM   Subscribe

Help me identify this pest affecting my aromatic herbs (w/ microscope picture) and your suggestions on Pyrethrin

Yesterday I noticed a very small, maybe 1 mm long elongated flying pest jumping off flying away from my mint; I also noticed extremely small (a fraction of a millimiter) tight cluster of little yellowish spots on the up side of some leafs.

So I took my microscope a examine the leaf, but I didn't expect to find this pest pic 1 pest pic 2 . It's possibily under a millimiter, moves rather slowly, two evident long antennae and six long legs.

It seems to me it's some kind of Aphid, but I don't know wheter one can tell the kind/type from the picture.

Additionally, today the local gardern store expert suggested me to use a Pyrethrin based insecticide w/ additional piperonyl butoxide and to apply it to the affected plants every week for 3 weeks. What's your experience with this allegedly low toxicity insecticide?
posted by elpapacito to Home & Garden (12 answers total)
I have nothing to add identification-wise, but pyrethrin was effective for my aphid issues back in the day.
posted by smoke at 8:05 PM on March 31, 2012

I have used a pyrethrin spray for indoor plants in the past--actually a pyrethrin/rotenone spray--and it has never caused me any harm, though it does harm the bugs! hooray! It has been effective at controlling scale insects and mealy bugs on my overwintering bay laurel tree.

As your linked Wikipedia article notes, this type insecticide works on the nervous systems of all insects, so will knock out any kind of aphids, so precise ID isn't necessary if that's the only reason you're looking for that. Pyrethrin is naturally occurring in certain plants and is quickly biodegradable when exposed to light and oxygen, so should be safe however you are using it. Were I you, I would probably not drink any of it (heh), but if you are using it as the label says, you should be fine.

Good luck and health to you and your mint!
posted by miss patrish at 8:17 PM on March 31, 2012

If you are concerned, why not try spraying with a dilute soap solution first? It's cheap, and you already have the ingredients on hand. If that doesn't work, then maybe move to the pyrethrin.

Here is a good ratio, though i just use dish soap.
posted by annsunny at 8:55 PM on March 31, 2012

Pyrethrin can affect people with asthma pretty severely and personally, having grown up on farms where they used it very liberally (like misters inside the buildings so everything gets covered in it) I think it's a lot more toxic than we know. Breathing problems, skin problems and eye irritation are pretty common. I definitely wouldn't use it indoors.
posted by fshgrl at 9:00 PM on March 31, 2012

You can try washing them off plants with a hose. It will reduce their numbers, but this is not a permanent solution. Also, if you can get ladybugs, they should keep the population under control. Other than that, make sure that the plant is happy and healthy, pests attack weak plants.
posted by leigh1 at 9:21 PM on March 31, 2012

That is an aphid nymph.

With some furthur googling, looks like M. carnosum. Here is a picture for comparison.

I have always had good luck with pyrethrin, and never worried about eating plants treated with it, after a good rinse. I would also recomend diluting some and giving the soil a good soak. If there are aphids there are probably eggs.
posted by St. Sorryass at 9:48 PM on March 31, 2012

Pyrethrin is a neuorotoxin, and as such should be a much later line of defense. I wouldn't use any Pyrethrins around pets or kids ever, and really, it's overkill at this point when you've got just a few bugs. If I need something beyond soapy water I use neem oil, though 9 times out of 10 regular blasting with the hose is enough control.
posted by oneirodynia at 10:45 PM on March 31, 2012

Check for ants, they may cultivate aphids.
posted by hortense at 10:54 PM on March 31, 2012

Response by poster: Thanks for help guys! Indeed I found more developed specimens, it's certainly aphids. Pyrethrin is proving to be effective already with one application.
posted by elpapacito at 5:18 AM on April 1, 2012

Response by poster: Oneriodyna thanks for your "physical removal" recommendation and neem oil, I'll experiment with this approach the next time.
posted by elpapacito at 5:20 AM on April 1, 2012

Many gardeners use praying mantises as a natural aphid killer. Aphids are like chocolates to mantises.
posted by Thorzdad at 7:10 AM on April 1, 2012

Response by poster: Nice idea thorzdad, they are also beautiful. Here's a video of ladybugs larvae, the other mortal enemy, attacking aphids.
posted by elpapacito at 9:29 AM on April 1, 2012

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