Gall Talk

Mon. Nov. 25, 2019

Click below to listen to my 2 min. Garden Bite radio show: Gall Talk

It’s time for the Gall Talk. As we face down the road to snowplows, we can still go out and look for them!  First up, what are they?

Pine oak rust gall

Galls are abnormal growths that occur on leaves, twigs, roots, or flowers of many plants. More gall dang information on Wayne’s Word….

Most galls are caused by irritation and/or stimulation of plant cells due to feeding or egg-laying by insects such as aphids, midges, wasps, or mites. Some info from an offbeat site that’s fun. Scientistseessquirrel 

gall close-up by scientistseessquirrel

Some galls are the result of infections by bacteria, fungi, or nematodes and are difficult to tell apart from insect-caused galls. Seeing the insect or its eggs may help you tell an insect gall from a gall caused by other organisms. Morton Arboretum has plenty to say about galls. 

Crown gall caused by a bacteria photo from Planet natural

Galls may appear as balls, knobs, lumps, or warts, each being characteristic of the causal organism. In addition to the unusual structure of galls, they draw attention due to their range of colors: red, green, yellow, or black. Factors such as weather, plant susceptibility, and pest populations affect the occurrence of galls on plants from year to year. 

One of the most common galls found in the Midwest is the maple bladder gall, a pouch-like growth on the leaves of maples, especially silver maple, caused by an eriophyid mite. Clusters of small galls form on the leaf surface as they expand in spring. The galls change color from light green to a bright red and eventually to black as the season progresses. The elm finger gall is also caused by an eriophyid mite.

Maple bladder gall photo by State by State gardening

Oaks have a lot of Gall!  And yes, they really do.  More information from Washington State.   Wasps use Oaks as a home.  These types of wasps do NOT sting!

Spotted galls caused by the speckled gall wasp (Besbicus mirabilis). Photo by Anne Schuster.
The poop gall on a choke cherry… caused by the fungus Dibotryon morbosum

I have a Hackberry tree that’s notorious for having psyllids, which cause galls on the undeside of the leaves.  For this tree, in this instance, with this insect, the psyllid, it doesn’t hurt the tree. (I had a tree service tell me I needed to spray the tree for aphids, this is why you MUST check out credentials!)

My hackberry

The gall of using galls for decoration!