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Garden Help Desk: Identifying and handling growths in your yard

By USU Extension - | Aug 20, 2022

Courtesy Meredith Seaver

Galls can grow at the soil line on tree trunks. Over time, they can become woody.

These strange growths are taking over our backyard. At first, they appeared to be aspen roots coming up through the ground, but upon careful examination, maybe not. They are varied in size, but many are the size of a small cow pie and are scattered around the entire backyard. They are hard like a root, but flat. This is the first year we have had this issue. Can you tell from the pictures what they are and what I can do about them?

Yes! Those growths in your photos look like crown galls. They’re caused by a bacteria called Agrobacterium tumefaciens, a bacterial that is harmless to you but a problem for susceptible plants. The bacteria enter trees through wounds on the roots and cause galls on a wide range of trees and shrubs. Poplars like your quaking aspens are very susceptible to crown gall.

Plants that are infected with crown gall will develop dense, tumor-like galls on their roots and trunks. You might even find an occasional gall on a branch. As you’ve seen with the galls in your lawn, they can be very woody, with a rough surface. Crown galls can interfere with the movement of water and nutrients in a tree and reduce their vigor. Infected trees are also more susceptible to winter injury, drought stress and other diseases.

Unfortunately, galls can encircle the small trunks of young trees and kill them. Trees that are well-established seem to tolerate the galls, so continue to give them good care.

Agrobacterium tumefaciens can be very difficult to get rid of once it’s established in a landscape, and infected trees and shrubs can’t be “cured,” so prevention is the best control method.

Courtesy Meredith Seaver

Large galls on tree roots can make mowing difficult. Expanding tree rings with bark mulch can eliminate the need to mow and disguise the galls.

Inspect new trees and shrubs carefully before planting, especially willows, poplars, roses and fruit trees and reject any that have galls on their roots or stems.

If you already have infected plants in your landscape, avoid trees and shrubs that are most susceptible to crown gall when you’re selecting new plants for your landscape.

Agrobacterium tumefaciens is a soil-borne bacteria. Avoid moving soil near infected tree to other areas of the landscape.

If you need to prune infected trees and shrubs, disinfect your tools afterward with a 10% bleach solution (1 part bleach to 9 parts water)

But what about the root galls that are showing up in your lawn? Trying to remove the galls won’t provide any benefit to your trees and could end up spreading A. tumefaciens farther into your landscape. If large galls near your trees are interfering with mowing, consider expanding your tree rings and covering the area with bark mulch. That will disguise the galls and eliminate the need for mowing over them.

Courtesy photo

Crown galls on roots appear small at first but can continue to grow. Removing root galls that show up in lawns will not improve the health of the tree.

There is something eating my strawberries. Some of them are eaten on the inside. I found lots of these insects there. Is there a way to control them?

These look like wireworms, the larvae of click beetles. The larvae spend their time in the soil, feeding on underground plant parts — roots, crowns and newly planted seeds of a variety of plants. Some species feed on the larvae of other beetles or on decaying organic matter.

There are several species of click beetles. They get their common name from their habit of flipping themselves into the air and making a clicking sound. Click beetle larvae — wireworms — are slender and about one-quarter-to-one-and-one-quarter inches long. They may look like worms, but they have six short legs near their heads. Your wireworms are dark brown, but they can range in color from tan to black.

It would be very unusual to see foliage or fruit damage from wireworms, so the original culprit was probably something else.

Wireworms prefer cool, damp habitats. Letting the area with the berries dry a bit between watering and removing any leaf litter or other debris around the plants will help to reduce the habitat for these insects. Using this tactic may also be helpful in reducing the population of whatever pest has been causing the damage to your strawberry fruits.

Courtesy Meredith Seaver

Crown gall on tree trunks is most common at the base of the trunk but can also develop higher on the trunk or even on branches.

Wireworms aren't a common problem for most gardeners, but they can feed on roots the roots and crowns of many plants and may also feed on newly planted seeds.


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