Anyone who has ever kept a few pot plants about the place will most certainly have seen evidence of spider mites, even if they do not realize what they actually are. A spider mite is a creature which spins a ball of web to hide in right under the leaf of plants inside and outside in the garden. What they need to flourish is a very dry atmosphere and this is why they affect house plants so much.
The damage they do to plants, whether in the garden or in the home is quite horrendous really. They burrow into a leaf and suck the life out of it much like a blood sucking insect. It gets under the leaf since this is where the weakest part is and it is easy for them to invade here. The only time that someone will know that they are present is when they start to see blotchy dried marks on the leaves, but by this time the end may be very near.
There are several ways to discourage their actions but it does take some careful examination to keep them at bay. In the home, where there are few plants, just keep an eye on the undersides of the leaves when dusting around. If any of this fluffy white material is seen, merely brush it off. It does, however, indicate that the area is much too dry so try putting a saucer of water near the plants or put a stone in a pot of water and sit the plant on that. The evaporation of the water will reach all the underside areas and this puts off the creature completely.
In the garden, again, look at some leaves if they look like they are wilting. If there is too much plant life out there, when watering, make sure to spray the underside of the leaves at the same time. Those plants that have been heavily infested should be removed immediately and burned instead of being put in the compost. By burning, the creatures are killed off so they will not come back onto healthy plants. Neem oil spread on the underside of leaves may well work on house plants, but this is too labor intensive for garden plants for sure. It may be good to look into ways to control these creatures by getting other bugs to eat them up instead. Lady bugs are a great friend in the garden and will rid the place of these plus other creatures too, so never kill a lady bug off no matter what happens.
Plants which have been invaded are naturally susceptible to any other kind of infection too. This is why it is so important to keep an eye on things. As with us, a hole will be used for infection to gather and spread so a plant will act like us when we have an infection. Limp leaves and a general malaise will overcome the plant no matter what we do to it. When it gets like this, it may be time to ditch it and start again.