Could be a fungus like Vladimir said, could also be an insect egg or just dirt on a bit of fluff. However, I'm more concerned with how dusty the leaves are. I may just be dust or it could be the beginnings of a spider mite infestation. It's a good idea to wash off the leaves from time to time, like maybe every 4-6 weeks. Take them outside and hose them off, or if that's not possible, put them in the shower and shower them off with cool water. Then let them drain well and put them back where they were. It helps prevent spider mites as they're attracted to dusty plants. And your plants love the rinsing off!

Sounds like a really cool title for a children's book. I'd say you have VOLES, my dear. When you water or it rains, they will tunnel through the soft earth, munching on your plant's roots. Moles and gophers and shrews (and snakes of all kinds), use their nifty tunnels to get around your yard subteranean - like a handy-dandy animal subways. Crickets use them, earthworms, and slugs, too, and lots of other critters. Some good for your garden and some that don't seem to be so good. I've lost tuberose salvias and my favorite tea roses; tulips and petunias, even cactus roots. If its edible, they will eat it! I've tried various things, like tarpaper collars around my roses and concrete or rock barriers, even strips of sheet metal buried around them. The tarpaper worked pretty good until it disentigrated, but eventually, mice burrowed through it and then it rotted to dirt. Flooding does no good, as those tunnels are hundreds of feet long. Those holes will never fill completely up. I've tried it. :) If you have a serious vole (or other rodent) problem, like I do, your yard may be completely undermined with tunnels that links with your neighbor's, and their neighbor's, and so on...hence you may find a flower in your yard (or weed) that you didn't plant or never saw before. Birds can bring carry them in or deposit them in your garden, via their poop, that's true, but so can rodents. Rodents carry seeds back and forth through those tunnels to and from your place. Keeping things in balance with Nature is what works best for me. If we can stop fighting all the elements of nature and work with it, we will get better results and enjoy gardening even more. I sink bottomless buckets in the ground for barriers for my big lilies, around berry bushes and roses, and even some of my garden plants, like my tomatoes, and that works really great. For shallow rooted plants that send out roots horizontally, these don't work so well. Planting daffodils, irises, liriope (Monkey grass), garlic, zinnias and stinky marigolds around the borders of my flower beds and/or around blueberry bushes, roses and strawberry beds, even apple trees, is about the only things I've done that works relatively well for an indefinite period of time, without killing the beneficial micro-organisms in the soil and harming animals like shrews and earthworms and preditory insects and snakes. Garlic really does a great job warding off rodents from my roses and they both mutually benefit from one another. Daffodils, irises, and liriope are poisonous so rodents just don't dig 'em. I think we gardeners and farmers will always have our challenges, but isn't that what makes our successes so awesome! ~ SweetAnnie4u

well if it were a battery operated one I would suspect the need of new batteries. Or that it's line of site to it's transmitter receiver was blocked. Have you checked your mouse settings in control panel to see if possibly some settings went awry? Check the surface you have it on, sometimes they do not work well on very shiny or glass like surfaces. What kind is it exactly? brand and type.

Happens to me, perhaps once a week or less. I usually have to do a power off shutdown.