Fruit flies - Flies develop in overripe fruit and become abundant in homes.

Wasps and hornets - Abandon nests at the end of the season. Workers are killed with cold weather and only females overwinter.

Boxelder bugs - Invasions of homes accelerate with cool weather. Massing of bugs occurs on south-facing sides of buildings on warm, sunny fall days.

Hackberry blistergall psyllids - Adults move into homes and to shelter of other overwintering sites.

Aphids on trees - Overwintering eggs are laid as long as weather permits.

Poplar twiggall fly - Galls become obvious as aspen leaves fall.

Oak bulletgall wasp - Adults begin to emerge in late month.

Needle drop of pines - Not insect-related, pines naturally shed old needles in fall.