Spider Mites

This damage is indicative of a large infestation of spider mite. These are tiny insects related to spider tht suck plant sap and chlorophyll from the leaves, causing the speckled appearance we see on these leaves. Control can be hard with a large infestation. Begin by removing all the infected leaves and destroying them. Use a spray of neem oil, or insecticideal soap, or other control specifically rated for spider mites. Be sure to spray the underside of the leaves where the invisible eggs and nymphs are found. Usually it is best to spray for two to three weeks, then quit for a while unless you see another generation begin to cause damage. Overspraying can kill a number of other insects that prey on these pests. You can also help keep the population of pest mites down by occasionally washing off the leaves of the affected plants early in the morning (and allowing them to dry throughout the day).

This looks like it could be spider mites, and it looks like there may be a bad infestation. We've included a link so you can see what these little sap sucking spider-like organisms look like, but at this stage of damage, you may want to remove the affected leaves and treat with an appropriate pesticidal product as recommended below, or in the web link provided. For future reference, if you catch the problem before it gets too bad, you can control them by spraying with neem oil or pesticidal soap, which can be purchased at most garden centers. Be careful to read the labels and apply any of these types of products properly. Be careful to spray the undersides of the leaves, the stems, and the tops of the leaves. Repeat the application as recommended on the product label to kill any new mites that hatch from eggs afer the first application.
http://www.ipm.ucdavis.edu/QT/spidermitescard.html

It does look like spider mites. If you can knock some off on to a piece of white paper you might see them crawl around, but if you take your finger and give them a swipe, you should see a small brownish-red smear. Unfortunately indoors is a real breeding ground for them as the temps are comfy and there's little air circulation - they love that. A couple of things you can do. If it is a sturdy cactus give it a good hard blast of water from a hose to remove the webs and kill as many as possible for the first pass. After it has had a good few days to dry out take a look and if you see any residual, use a spray bottle of 50/50 rubbing alcohol and water (preferably distilled) and give them a good spray down. You may have to follow up a few times but this could get rid of them. You can try using a commercial miticide that you buy at the garden center but cacti and succulents are real sensitive to most pesticides. See if the container offers any info on using with succulents.

This is possibly being caused by a large population of Spider Mites. They can only be seen with a magnifying lens and suck plant sap and chlorophyll from the leaves, causing the speckled appearance we see on these leaves. You'll want to verify this ID by looking at the link we've included and examining the upper & lower sides of the leaves with a magnifying lens. You may also see some very fine, disorganized, webbing with mites in the web. If you confirm, you can use insecticidal soaps or horticulture oils to control them, but don't over-use these products because you'll probably be killing other beneficial mites that are natural enemies of these mite pests. When many of the predatory/natural enemies are killed, the spider mite pest population can sky rocket and get worse. You can also help keep the population of pest mites down by occasionally washing off the leaves of the affected plants early in the morning (and allowing them to dry throughout the day). Here's a web-link with more info:
http://www.ipm.ucdavis.edu/QT/spidermitescard.html

This is being caused by a large population of Spider Mites. These tiny spiders (can only be seen with a magnifying lens) suck plant sap and chlorophyll from the leaves, causing the speckled appearance we see on these leaves. You'll want to verify this ID by looking at the link we've included and examining the upper & lower sides of the leaves with a magnifying lens. You may also see some very fine, disorganized, webbing with mites in the web. If you confirm, you can use insecticidal soaps or horticulture oils to control them, but don't over-use these products because you'll probably be killing other beneficial mites that are natural enemies of these mite pests. When many of the predatory/natural enemies are killed, the spider mite pest population can sky rocket and get worse. You can also help keep the population of pest mites down by occasionally washing off the leaves of the affected plants early in the morning (and allowing them to dry throughout the day). Here's a web-link with more info:
http://www.ipm.ucdavis.edu/QT/spidermitescard.html

Shrimp plants are notoriously difficult to grow indoors unless you have a greenhouse with full sun and high humidity, so don't feel bad! They are also prone to spider mites. I know you said your pests are smaller than mites, but mites are often so small that you need a magnifying glass to see them. Are the brown dots you're seeing the mites themselves or are they the damaged leaf tissue that the mites leave behind? (Mites are piercing, sucking pests that penetrate leaf tissue and suck out the chlorophyl.) Can you see them move? If you're not sure, put a piece of white paper underneath a leaf and tap the leaf hard. A few mites will fall off onto the paper. Also, use a misting bottle to spray the leaf axils and undersides of the leaves. If you see any webbing, that's a good indication that the plant has mites. This may sound harsh, but we suggest you get rid of this plant and buy yourself a house plant that is easier to grow indoors, one that will be more rewarding and give you less trouble. Unless this shrimp plant has great sentimental value, that's what we would do.

Spider mites usually congregate on the undersides of the leaves, and if the infestation is severe enough, youäó»ll see the webbing there. Another test is to hold a piece of white paper under a branch and shake it. If you see any tiny specks fall on the paper, and after a few seconds the tiny specks begin moving, those are mites. Symptoms of damage include flecking, discoloration (bronzing) and scorching of leaves. Injury can lead to leaf color loss and even plant death. Natural enemies include small lady beetles, predatory mites, minute pirate bugs, big-eyed bugs and predatory thrips. Spider mites are barely visible to the naked eye, and are difficult to control. Insecticidal soap can help, especially if the problem is caught early and the leaves, both sides, are sprayed well or spray with a strong stream of water. Or look for another product with "spider mites" listed on the label and make sure it is safe for strawberries. A straight insecticide will be ineffective because spider mites are arachnids, not insects, but there are organic controls such as Natria Insect, Disease and Mite Control.

This is possibly being caused by a large population of Spider Mites. These tiny spiders (can only be seen with a magnifying lens) suck plant sap and chlorophyll from the leaves, causing the speckled appearance we see on these leaves. You'll want to verify this ID by looking at the link we've included and examining the upper & lower sides of the leaves with a magnifying lens. You may also see some very fine, disorganized, webbing with mites in the web. If you confirm, you can use insecticidal soaps or horticulture oils to control them, but don't over-use these products because you'll probably be killing other beneficial mites that are natural enemies of these mite pests. When many of the predatory/natural enemies are killed, the spider mite pest population can sky rocket and get worse. You can also help keep the population of pest mites down by occasionally washing off the leaves of the affected plants early in the morning (and allowing them to dry throughout the day). Here's a web-link with more info:
http://www.ipm.ucdavis.edu/QT/spidermitescard.html