Habits
Grand Daddy Long Legs are generally nocturnal but are often seen in daytime. Groups of adults are most common in late summer and early fall when they look for places to lay their eggs. Keep boxes, debris and newspapers out of basements and crawl spaces to eliminate their nesting areas.
Indoors
Grand Daddy Long Legs will seek the shade and coolness of houses. Keep all doors, windows and screens sealed tightly to keep them out. Clean all dead flies and insects off window frames and sills because they like to eat them. Sticky traps along baseboards will catch them. Insecticide sprays containing pyrethroids will kill them.
Outdoors
To control an outdoor infestation of Grand Daddy Long Legs, eliminate their food sources. They feed on small insects, such as aphids and plant material. To get rid of the Grand Daddy Long Legs, reduce their sheltering and hiding places. Remove piles of rocks, wood and other organic material that provide damp, shady places.