Written by Carole Knight

Mushrooms are the visible structures of the unseen fungi growing in our landscapes. Think of mushrooms as the flowers and fruits of the fungi world. The mushrooms these fungi produce may cause a concern depending on where they are growing. Mushrooms and other fungal growths can be unsightly and are a concern since some may be toxic to children. They can be found growing in mulch, turf and landscape beds.

There are many types of mushrooms and other types of fungal growth including puffballs, stinkhorns and others. Slime molds, though not a fungus, can appear as a slimy, oily or powdery growth on lawns, mulches or wood.

Unfortunately, it is almost impossible to prevent mushrooms and similar organisms from growing. Many fungi get their energy from decomposing dead organic matter. They are actually a part of the natural recycling process. There are no chemicals that effectively kill all the fungi that cause mushrooms. You can remove the mushroom, but you must remove the fungus to keep the mushrooms from returning. To remove the fungus, you will need to remove the organic matter upon which it is growing.

There are several possible sources of food for fungi.

• Buried wood, roots or other organic matter. Dig up and remove the source.
• Thatch under lawns. De-thatching and aerating the lawn may reduce mushrooms.
• Mulch, especially mulch that is too thick. (Greater than 3 to 4 inches in depth).
• Piles of leaves, logs and limbs. Remove them if you need to discourage mushroom growth.

Even if you remove the food source, the mushrooms may still continue to grow. Removing the food should help to some extent. Mulches can be removed, properly composted and used again.

Some mulches are more prone to producing mushrooms and other fungal growth. Proper mulch selection, application and care can reduce mushroom problems.

• Bark chips from mature, old pine or cypress trees decay more slowly and are less prone to mushroom problems than chips from other types of trees. However, this is only true of chips from old, mature trees. Chips from young pine or cypress trees do not have this advantage.
• Wood or bark mulches from hardwood trees can be more prone to fungal problems than bark mulches from old pine or cypress trees. Composting these mulches before use will help reduce the chance of producing mushrooms.
• Mulches from bark or wood products should be composted for at least 6 months before being used as mulch. Add a nitrogen source to the mulch and keep the mulch moist and turned during composting
• Do not allow mulches to get dry. This leads to an increase in fungal activity. Then when the mulch gets wet again, mushrooms appear. Apply mulches 2 inches deep and wet the mulch well at application. Keep the mulch moist but not overly wet.
• Finer textured wood or bark mulches can be more prone to problems. Use coarser textured mulches and/or apply mulches in a thinner layer.

Mushrooms that grow at the base of trees (also called conks) are usually an indication that the interior of the tree is decaying. This can indicate that a tree is at risk to fall. If you see mushrooms (or conks) attached to tree limbs or roots, contact a certified arborist to evaluate the tree to see if has become a hazard.

Another fungal problem we see in mulch piles involves hydrophobic fungi. When mulch is applied too deeply or is piled up in areas, the mulch can be infested by these fungi that waterproof the mulch. Water will then no longer able to penetrate the mulch and the plant roots can dry out and die – even though the plants are being watered. This is especially a problem with woody mulches that are applied too deeply. Dig into affected mulches and you will notice that they are dusty dry. To prevent problems, do not apply these mulches more than 2 inches deep.

In addition, mulch piled against the base of trees can lead to tree damage and death. Pull mulches slightly away from the trunks of all trees and shrubs.

Once you begin seeing mushrooms, it may be best to just ignore or remove the mushrooms you can see and wait for the fungus to quit producing more mushrooms. This can take a while depending on the fungus, weather, etc. These fungal fruiting structures are often short-lived but interesting to watch. Try to ‘enjoy’ your landscape oddity until it runs its course.

 

By NG Turf

This time of year it’s important to keep an eye out for two pests that often invade Georgia lawns. Both fall armyworms and also webworms are voracious caterpillars that can infiltrate in large numbers and damage your grass. Armed with information about how to find and annihilate them, you can keep your lawn healthy and beautiful.

Fall Armyworms 

As their name suggests, fall armyworms usually begin their rampage in early fall, but they may show up as early as July or August, feeding on our lush grassy lawns. Some sightings have already been reported this year, and because the striped caterpillars appear in large numbers, they can cause major damage in short order.

A pest for more than a century in the Southeast, the adult moths migrate each spring from Florida, where they overwinter in the mild climate. Each moth lays a few dozen to a few hundred eggs along the way as they move northward, building populations exponentially throughout the summer months. They reach most areas of Georgia by early fall and continue to reproduce—and eat our grass—until the first frost.

 

Damage
Armyworms harm virtually all turf grasses by chewing the plant tissue and creating ugly webpatterns in the leaves. The armyworm larvae strip foliage in one area of the lawn and move, usually all together, to the next source of food. Moving en masse like an army earned these destructive critters their military designation.

Damage varies in severity depending on the type of grass and the overall health of the grass prior to the infestation. Armyworm damage rarely kills a lawn on its own, but it can significantly weaken your grass, making it far more susceptible to failure from drought and disease.

 

Win the War
Watch for birds clustered in a particular area of your lawn, often an early indication your yard has been invaded by armyworms. The caterpillars are dark in color with several light stripes down the length of the body and an inverted “Y” at the head. Young armyworms measure ½ to ¾ inch long, reaching 1-1/2 inches before burrowing into the soil for the pupa stage. They emerge two weeks later as adult moths, laying eggs to begin the cycle again.

If the worst happens and armyworms do march into your lawn and flowerbeds, treating with insecticide is your best defense. The University of Georgia extension office recommends Bt insecticides, which are nontoxic to humans and eradicate caterpillars without harming beneficial insects in your yard. Several brands are readily available at home and garden centers.

 

Sod Webworms
Another dastardly caterpillar that feeds on Georgia lawns this time of year is the sod webworm. The adults appear as small gray or brown moths, which scatter eggs as they fly around the yard. Once hatched, the caterpillars chew on the tender grass blades, creating notched, ragged edges. Sod webworms prefer newly established lawns, and they attack many grass varieties, including Bermuda, Zoysia, Centipede, and St. Augustine.

A major infestation can wipe out a lawn in a matter of days, so if you notice irregular brown patches in your otherwise green yard, try a soap flush in the affected area to confirm. Add two or three tablespoons of liquid dish soap to a gallon of water and spread with a watering can over a small 3-foot by 3-foot section in the affected area. If webworms are present, the soap solution will force the caterpillars to the surface of the lawn.

Look for caterpillars up to ¾ inch, covered in fine hairs with a dark head. Their bodies vary in color from light pink or green to a yellow brown. Treat the infested areas with Bt insecticide in the early evening, when the caterpillars begin to feed.

If you have additional questions about pest infestations or unidentified damage to your grass, give us a call at 706-800-4010.

 

Granulate ambrosia beetle, Xylosandrus crassiusculus (Mot.) [Previously known as the Asian ambrosia beetle]

Introduction: Granulate ambrosia beetle (Fig. 1) is a serious pest of woody trees and shrubs in Georgia. These tiny beetles were first detected in South Carolina in the 1970’s and have spread across the southeastern US.

Host plants: Woody ornamental nursery plants and fruit trees are commonly affected. In spring or even in late winter (around mid-February), a large number of beetles can emerge and attack tree species, especially when they are young. Some highly susceptible tree species include Styrax, dogwood, redbud, maple, ornamental cherry, Japanese maple, crepe myrtle, pecan, peach, plum, persimmon, golden rain tree, sweet gum, Shumard oak, Chinese elm, magnolia, fig, and azalea.

Biology: The female beetles land on the bark of woody trees. Then, they bore through the soft wood and vascular tissues (xylem vessels and phloem) of the tree. They settle in the heartwood and begin making galleries. Eggs are laid in these galleries. Adults introduce a symbiotic fungi into the galleries as a food source for the developing larvae. Click here to read more.

Although Georgia has received rainfall over the past few weeks, most of the state is still in a drought. The rain has improved the situation, but whether the rainfall will continue is uncertain.

Many plants have sustained damage and died as a result of the continued dry conditions in the fall. Much of the state received little or no rain from early August until December. Read more