Those Dusty Spider Mites

Remember when you were little and you put your thumb over the end of the hose and sprayed everything in sight? Bet you didn't know you were training to become a great spider mite killer someday. Hot, dry weather and dusty, dry leaves are just the ticket for spider mites. Keeping plants cool and wet discourages these critters. Right now, in the hottest, driest part of summer, is exactly when we should be spraying water.

Prevention Is Key
Spider mite populations can explode quickly, and it's hard to see the actual mites themselves, so watch for telltale signs of their activity such as tiny webbing and dull, mottled looking leaves or needles. Mites attack a broad range of plants. Evergreens are especially vulnerable when hot and dry summer weather hits.

Hose Them Down
The very best miticide is a good hosing down. Attach a nozzle to the end of the hose. Use one that will squirt a hard stream all the way up a tree. Since spider mites can be all over leaves, try to cover every branch and twig with a hard spray of water. Some of the little monsters are crushed by the force of the water, and the others just go away. During the hot summer months, try to play in the water, er, wash all the plant leaves about once a week. If spider mites don't get a foothold, they'll never be a problem.

Spray Them Early
The best time to give your plants a shower, especially shrubs that are susceptible to diseases, such as roses, is early in the day. This allows the water on the leaves to dry before nightfall. Wet foliage all night long can encourage the development of fungal diseases.

Soap Them Away
If you still have mites after all this spraying, try mixing some insecticidal soap with the water to kill the pests. Mites can't stand soap, and your leaves and needles will be less dusty too. 

Read more from the national gardening association.