Behavior of Solenopsis invicta (Hymenoptera: Formicidae) in pecan orchards

Pecan, Carya illinoensis (Wangenh.) K. Koch, orchards provide an important habitat for the red imported fire ant, Solenopsis invicta Buren, and orchards from middle to southern Georgia were heavily infested. Honeydew produced by blackmargined aphids, Monellia caryella (Fitch), on pecans was an important source of carbohydrate food for S. invicta, which were found foraging at 9-m heights in trees. Mowing of orchard ground cover caused a change in the ratio of S. invicta on the ground to that in trees but was not correlated with outbreaks of M. caryella in trees. S. invicta was a major predator of eggs, larvae, and pupae of a green lacewing, Chrysoperla rufilabris (Burmeister), and of the pupae of Allograpta obliqua (Say) in pecans but had little effect on the eggs of Hippodamia convergens Guerin-Mineville. A close mutualistic relationship between S. invicta and the mealybug Dysmicoccus morrisoni (Hollinger) was discovered. S. invicta promoted the development of colonies of D. morrisoni on callus tissue located on the main stem of trees by covering the colony with soil and debris, by defending the colony, and by collecting honeydew