Life History of a bullet gall wasp, Disholcaspis quercusvirens (Hymenoptera: Cynipidae)

The stem galls of a bullet gall wasp, Disholcaspis quercusvirens (Ashmead), are disfiguring to live oak (Quercus virginiana Mill.) trees in Florida nurseries and landscapes. The presence of galls reduces tree aesthetics and value, alters tree architecture, and concerns clients enough to return tree shipments to the growers. Little was known about stem gall and asexual wasp development, and the sexual generation wasps and their gall type and location were undescribed. Thus, the life history, seasonality and gall development of both D. quercusvirens generations were determined. Stem galls on ‘Cathedral’ live oak trees in Clay Co., Florida, were either caged with a fine white mesh or periodically cut and inhabitants were reared from June 2007 to September 2008. Branch and gall dimensions of developing stem galls were recorded, and adult D. quercusvirens and natural enemy emergence patterns were observed. The asexual generation developed in 7-8 months. Asexual wasps laid eggs into dormant buds in November and December, which initiated the sexual generation. Sexual wasps developed for 4-5 months and emerged in April, after bud break and during shoot elongation. Species identification was confirmed by DNA analysis. Both generations were heavily parasitized.