Disappearance of mites and ants
I know this is strange asking why the red spider mites and ants have disappeared from the potted plants on my apartment's large terrace, instead of asking how to get rid of them, but I am. completely baffled. For 20 years, I have unsuccessfully battled (water spay, diatomaceous earth, neem oil, etc.) the red spider mites which usually demonstrate their serious damage to my plants by mid-July. They especially attack tomatoes, but do great damage to everything for the most part, except the sweet alyssum and marigolds. I also have a awful problem each year with ants invading my living room, coming in from the terrace (ant traps by the terrace door takes care of them). However, this year, no sign of either spider mites (or an abundance of lady bugs) or ants. I live in Charles Village in Baltimore and a friend of mine in nearby Roland Park recently mentioned that her kitchen hasn't been invaded by ants either, which is usually abig problem in her home in the summer. What is goingon?
The rise and fall of insect populations is heavily dependent upon weather conditions directly, and indirectly then the weather impacts either the insect's predators or their food source..
Ants, for example, become active in spring during a warm spell and then, when it gets cold again, they turn to warm homes to forage. This is usually temporary until weather is steadily warm, then they head outside to stay. Liquid bait traps usually work well on the early spring foragers, though you have to be careful not to clean up the pheromone trails they leave for each other to help find the bait.
Mite populations, too, vary. Here is our website info, which may have some control ideas you haven't tried yet: http://extension.umd.edu/hgic/spider-mites-flowers-and-groundcovers