Rainy days contribute to toadstool pop-ups
Editors note: Throughout the growing season, Mike Hogan, OSU Extension Educator for Agriculture & Natural Resources in Franklin County, will answer gardening questions submitted by Dispatch readers. Send your questions to hogan.1@osu.edu.
Q: I have recently noticed that several toadstools have popped up in my lawn. They look like the white mushrooms you buy in the grocery store, are they edible? Why did they suddenly appear?
A: A variety of mushrooms can grow in a lawn. The term "toadstool" typically refers to a mushroom that is toxic, poisonous or simply inedible.
Although it's not clear the exact species of mushroom that has appeared in your lawn, we generally do not recommend eating wild mushrooms without positive identification. An old adage says that “there are old mushroom hunters and bold mushroom hunters, but there are no old bold mushroom hunters!”
Most of the species of mushrooms that grow in lawns are not poisonous. A few species will make people and pets sick.
Mushrooms that appear in the lawn are naturally occurring fungi that thrive when suitable conditions occur, and a food source is present. The rainy conditions experienced over the past several weeks provided suitable soil moisture for the mushrooms to begin to grow. The food source that spurs mushroom growth is any type of organic matter in the lawn. This includes decaying tree roots underground, a thick layer of thatch in the lawn, pet waste, and even
droppings from wildlife such as rabbits or deer. There is no need to remove the mushrooms as they will not last very long.
Q: Several large black walnut trees in our landscape have tent caterpillars on many of the branches. Will these insects kill these large trees?
A: The weblike nests that you are seeing at this time of the season are actually the result of fall webworm (Hyphantria cunea). This caterpillar insect has two generations each season but the second generation is much more noticeable in late summer and fall because of larger second-generation nests.
Black walnut (Juglans nigra) is the most common host for the outbreak, and large mature trees can sometimes have nearly every branch tip wrapped in webbing created by this insect. In the absence of black walnut trees, fall webworms will feed on oak, poplar, hickory, poplar, ash, sweetgum, redbud and
even apple and other fruit trees.
Fall webworms feed in groups inside their protective webbing. The insects feed on the tissue of leaves inside the webbing, consuming everything except the leaf veins.
Typically, only the leaves inside the silk webbing are consumed by the insect.
Fall webworms are more of an aesthetic nuisance than a threat to the long-term health of trees, so control is rarely warranted, especially on large trees such as yours. The exception to this would be newly planted young trees that are infested with webworms. In this case the nests and its contents of caterpillars can be removed from small trees by hand and deposited into a bucket of soapy water for disposal.