Oak Gall Apples

Oak Gall Apples by meadow.

These are high in the tree by Schmitz entrance.
The adult female wasp lays single eggs in developing leaf buds. The wasp larvae feed on the gall tissue resulting from their secretions, which modify the oak bud into the gall, a structure that protects the developing larvae until they undergo metamorphosis into adults.

Our native oak trees are starting to host the native oak gall wasps that create these green 'apples' on the oak branches. These two in the pictures are in the preserve now and more will appear.  It's a mixed bag as to whether they are harmful or not. (See below)

"Neuroterus saltatorius Edwards, commonly referred to as the jumping gall wasp or the jumping oak gall, is an oak gall wasp that occurs on a variety of white oak species in North America. It is native to the western United States, occurring on several oak species that range from Texas to Washington State." 

"Most galls, especially on leaves, do not hurt the oak tree, and the wasps aren't harmful to people either. In fact, like many insects, the wasps inside these galls are a beneficial source of food for our native wildlife, including many species of birds, as well as mammals such as opossums and raccoons."

"There are several cynipid gall wasps that make galls on oaks in the PNW. One potentially damaging cynipid gall wasp in nursery production is Bassettia ligni, a native insect that causes twig galls on Oregon white oaks. Our results provide evidence for a plant-mediated impact of an invasive oak gall wasp on a native butterfly and suggest that gall wasps could act as superior competitors, especially when they occur at high densities."