-- This wasp is among over 600 gall insects that attack the oaks in
the United States. Gouty oak gall is most common on scarlet, red, pin,
water, and black oaks. In heavy infestations, twigs, large branches,
and occasionally entire trees may be killed.
the Insect. -- Adults are small, black, cynipid wasps with an oval,
shiny, and slightly compressed abdomen. The larvae are white and globe-shaped.
Injury (figure 40a). -- Galls are irregular, globose, woody, 1.5
inches (38 mm) in diameter, and encircle the twigs and small branches.
They sometimes occur so close together that they form nearly continuous
masses (figure 40b).
-- This species has alternate generations. The first produces small
blisterlike galls on leaves in the spring. The second produces gouty
galls during the summer.
-- Natural controls are generally adequate. Prune galls from small trees