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I have a sensitive plant (Mimosa pudica) that has gotten infested with tiny black bugs. They're roughly 0.76mm (3/100ths of an inch) long. I'd like some help identifying what they are and how to treat them. I've sprayed them with Neem Oil. That seems to kill them, but then they appear again. Something is wilting the leaves on the plant, turn them brown, and making webbing (similar to a spider) on the leaves--especially the new shoots. When I poked the black bugs with a pin, some of them would disappear (jump, perhaps?).

I've circled one of the bugs with a ballpoint pen for size comparison: bug and pen

Here's the little bugger under a microscope: bug walking

I found this in the webbing: eggs

I also found this mite on one of the dead leaves:

Mite

Also on the dead leaf was this (an egg?): Mite Egg

All the microscope images are at the same magnification.

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    Amazing job presenting the facts. Fantastic way to ask a question here. Great work.
    – Evil Elf
    Commented Sep 15, 2017 at 12:32
  • Then that would mean blind spring tail...you are funny!
    – stormy
    Commented Sep 22, 2017 at 20:25

2 Answers 2

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+50

This insect looks like a blind springtail, which is an insect that feeds on fungi.

Google "soil biology primer" download this great manual on soil biology.

Look on page 26.

Here's another description:

The springtails are soft-bodied, oval or roundish shaped, primitive insects. Their bodies are made up of six or fewer segments and they lack wings. Although many species have small eyes, some are nearly or totally blind. Their antennae are segmented. They occur in a range of colors including whitish, yellowish, brown, gray, bluish, or black, and they may be mottled.

Collembola have biting mouthparts that are entognathous. That is, the mouthparts are mostly retracted into the head. Some springtails have mandibles with well-developed molars. Others are fluid feeders, having stylet-like mouthparts. For these springtails, on the ventral side of the first abdominal segment, there is a tube-like structure called a collophore. This structure is the site of water uptake.

A forked structure or furcula is located on the ventral side of the fourth abdominal segment. This structure is used to propel Collembola through the air. A springtail that is 3 to 6 mm long can leap 75 to 100 mm. When a springtail is at rest, the furcula is held in place by a clasp-like structure called the retinaculum that is located on the third abdominal segment.

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    Paul - I think it would help to add some of your credentials to your profile. The fact that you are a NOFA instructor, own and operate an Organic Landscape Care company, and you run the Soil Food Web NY will help people weigh your input.
    – That Idiot
    Commented Sep 19, 2017 at 14:05
  • For what it's worth, this is what came to mind for me as well. +1, but could you expand the answer to show some details on the springtail as well as comparison images?
    – J. Musser
    Commented Sep 21, 2017 at 23:22
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thrips

Check out this picture of a thrip. Very tiny, easy to control, not eradicate. They do not do webbing. That might be spider mite which I think is far worse than thrips. So there might be a couple of insect problems. Neem should work for both but spray only at night and you have to submit to at least 3 or 4 sprays a week apart. Wear a mask and long sleeves, long pants, glasses. This is 'organic' but still...read that label and instructions at least 3 times through before spraying.

Look beneath the leaflets using a strong magnifying glass. Webbing is either from spiders (your friends in the garden) or spider mites. Neem will help control both thrips and spider mite. I don't like killing spiders.

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  • stormy, are you thinking this is a not a blind springtail, and also that it might be both thrips and spider mites? Commented Sep 19, 2017 at 19:27
  • stormy, I wish I could combine yours and Paul's answers. I added more info to the question (I found a mite). The black bugs really look more more like blind springtails than thrips to me.
    – watkipet
    Commented Sep 19, 2017 at 20:33
  • Blind springtail, could be possible! Just went to look and at an early stage they don't have their 'spring tail'...
    – stormy
    Commented Sep 21, 2017 at 5:55
  • Paul's answer is a good one. I'd love to see this soil primer. But we have to ID the insects first. Blind springtail sure looks good to me.
    – stormy
    Commented Sep 21, 2017 at 6:00

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